TY - JOUR. T1 - Chlorophyll derivatives as catalysts and comonomers for atom transfer radical polymerizations. AU - Gajewska, Bernadetta. AU - Raccio, Samuel. AU - Rodriguez, Kyle J.. AU - Bruns, Nico. PY - 2019/1/7. Y1 - 2019/1/7. N2 - Copper trisodium chlorophyllin is obtained from natural chlorophyll, and is widely used as a major green food colorant in cosmetics and in medical devices. Copper chlorophyllin also proves to be an efficient catalyst and comonomer for atom transfer radical polymerizations (ATRP). Aqueous ATRP of poly(ethylene glycol) acrylate (PEGA) results in PEGA-chlorophyllin copolymers with narrow molecular weight distributions and a controlled content of chlorophyllin. The reactions proceed with first order kinetics, and the polymers molecular weight increases with conversion. The resulting copolymers could find application in drug delivery and in biomedical materials, or as solar energy harvesting materials. In order to suppress the incorporation of the catalyst into the ...

en] Due to an increasing need for polymers with well-defined architecture (diblock-, graft-, star-shaped copolymers), molecular weight and/or functional end-groups, the use of controlled radical polymerization (CRP) in scCO2 has started to gain attention. Among all the controlled processes, Atom Transfer Radical Polymerization has emerged as a robust tool for the preparation of polymers with well-defined molecular weight, architecture and chain-end functionality. In a very recent paper, we reported the first efficient dispersion ATRP of methyl methacrylate (MMA) in scCO2 using a fluorinated polymeric ligand that had a dual role, i.e., the complexation of the copper salt and the stabilization of PMMA growing particles. In this contribution, we extended this new system to the dispersion ATRP of styrene2, to the synthesis of diblock copolymers beads2 or to the preparation of PMMA particles by AGET ATRP. Because both ATRP and alkyne-azide Huisgens 1,3-dipolar cycloaddition relies on the use of a ...

CHEM 5384 Polymer Characterization II Lab 1: Atom Transfer Radical Polymerization of styrene Mengfang Li 01/29/2012 Introduction: In this experiment we were introduced the method to control a radical process to prepare well- defined and functionalizable polymers. Over 100 billion pounds of synthetic polymers were produced each year in United alone. Chain polymerization accounts 80% of these and by far free radical polymerization is the most commonly used reaction method in this category [1] . Radicals are very reactive and add quickly across the double bond to form polymers. This process will terminate if the chain end reacts with another radical. This can be observed by plotting the molecular weight as a function of conversion of monomer into polymer. As shown in Figure 1 for conventional method, high molecular weights are obtained at low conversion and remain at approximately same level throughout the reaction. The initiator (eg. BPO or AIBN) decomposes ...

ENGLISH ABSTRACT: The effect of various organic reducing agents, in the. form of monosaccharide reducing sugars, on the rate of atom transfer radical polymerization (ATRP) of n-butyl methacrylate and methyl methacrylate is reported in this study. The addition of the reducing sugars has a positive effect on the rate of ATRP. Up to 100% increase in the rate of polymerization was recorded, in some cases. These organic reducing agents have little effect on the molecular weight and molecular weight distribution of the polyin-butyl methacrylate) and polydispersity indexes remain well below 1.2. The molecular weight of the poly(methyl methacrylate), when glucose and galactose are added to the reaction mixture, compares well with the theoretical expected values. An explanation for these observations is the ability of the reducing sugars to reduce part of the Cu(II) species, that serves to deactivate the growing radicals, to Cu(I), thereby ensuring a shift in the equilibrium between active and dormant ...

Highly branched polystyrene was prepared by atom transfer radical polymerization of styrene with p-styrenesulfonyl chloride as an initiator. The molecular weights and molecular weight distributions of the polymers obtained at different ratios of the initiator to the monomer and different monomer conversions were determined by gel permeation chromatography. It was found that the molecular weights were higher than the calculated ones by assuming that one polymer chain was generated per p -styrenesulfonyl chloride molecule, and that the molecular weight distributions were broad with multi-peaks.

Reversible addition-fragmentation chain transfer or RAFT polymerization is one of several kinds of reversible-deactivation radical polymerization. It makes use of a chain transfer agent in the form of a thiocarbonylthio compound (or similar, from here on referred to as a RAFT agent, see Figure 1) to afford control over the generated molecular weight and polydispersity during a free-radical polymerization. Discovered at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) of Australia in 1998, RAFT polymerization is one of several living or controlled radical polymerization techniques, others being atom transfer radical polymerization (ATRP) and nitroxide-mediated polymerization (NMP), etc. RAFT polymerization uses thiocarbonylthio compounds, such as dithioesters, thiocarbamates, and xanthates, to mediate the polymerization via a reversible chain-transfer process. As with other controlled radical polymerization techniques, RAFT polymerizations can be performed with conditions ...

TABLE-US-00003 TABLE 2 Toner particles External additive (zeolite) Addition amount Addition amount of negative with respect to charge control External Aluminum 100 parts of Toner Toner resin D50t Average additive ratio toner particles No. particle No. Production method (part(s)) (μm) circularity No. (%) (part(s)) Example 1 (1) (1) Suspension polymerization method 0.3 6.3 0.985 (1) 1.8 0.3 Example 2 (2) (2) Suspension polymerization method 0.7 6.5 0.980 (2) 11.3 0.1 Example 3 (3) (2) Suspension polymerization method 0.7 6.5 0.980 (3) 7.0 0.1 Example 4 (4) (1) Suspension polymerization method 0.3 6.3 0.990 (4) 0.3 0.3 Example 5 (5) (2) Suspension polymerization method 0.7 6.5 0.980 (5) 22.5 0.1 Example 6 (6) (3) Suspension polymerization method -- 7.2 0.975 (1) 1.8 0.1 Example 7 (7) (4) Pulverization method 0.3 8.1 0.970 (1) 1.8 0.3 Example 8 (8) (5) Pulverization method 10.0 8.7 0.965 (1) 1.8 1.0 Comparative (9) (1) Suspension polymerization method 0.3 6.3 0.990 -- -- -- Example 1 Comparative ...

A novel cationic nanodiamond-polymer brush was synthesized by 2-bromoisobutyrate-modified nanodiamond (ND) surface-initiated atomic transfer radical polymerization of 2-(dimethylamino)ethyl methacrylate (DMAEMA). Elemental analysis, FTIR, HRTEM, TGA and zeta potential analysis were used to confirm the successful synthesis of ND-polymer brushes. It was shown that the ND-brushes were capable of condensing plasmid DNA into stable nanoparticles, protecting DNA from enzyme degradation. Transfection studies demonstrated that the ND-brushes could not only efficiently deliver plasmids into COS-7 cells, but also mediate higher expression than PEI25k with lower cytotoxicity. The green fluorescence of ND-brushes could also be detected by laser scanning confocal microscopy, making the nanodiamond-polymer brushes an excellent multifunctional gene vector with not only high transfection efficiency but allowing for bioimaging.. ...

Enzymes are environmentally friendly, non-toxic catalysts that have found many applications in synthetic polymer chem. However, until very recently no examples of enzyme-catalyzed, controlled radical polymns. were known. Here we review the nascent field of biocatalytic atom transfer radical polymn. (ATRP). The heme proteins horseradish peroxidase, Hb and catalase, as well as the copper-contg. enzyme laccase have been reported to display catalytic activity in activators regenerated by electron transfer (ARGET) ATRP of two model monomers, N-isopropylacrylamide and poly(ethylene glycol) Me ether acrylate. Bromine-terminated polymers, low polydispersity indexes, linear increase in mol. wt. with conversion as well as first-order kinetics indicate ATRP-type mechanisms. However, the first examples of biocatalytic ATRP also show that enzymes are much more complex catalysts than conventional ones ...

X- RAY INTEN S TY June 4, 1974 w E 3,814,607 CRYSTALLINE PHOTOPOLYMERIZABLE COMPOSITIONS WITH IMPROVED STORAGE LIFE Filed Aug. 7, 1972 DIFFRACTION ANGLE 29 United States Patent 3,814,607 CRYSTALLINE PHOTOPOLYMERIZABLE COM- POSITIONS WITH IMPROVED STORAGE LIFE William John Nebe, Wilmington, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del. Filed Aug. 7, 1972, Ser. No. 278,459 Int. Cl. G03c 1/70 U.S. Cl. 96-115 P 11 Claims ABSTRACT OF THE DISCLOSURE Predominantly crystalline photopolymerizable compositions containing a reducing agent such as 4-dimethylamino-3-propionyloxybenzophenone have excellent storage life without significant loss of photographic speed. BACKGROUND OF THE INVENTION Field of the invention This invention relates to photopolymerization, especially to predominantly crystalline compositions characterized in having high photographic speed. The invention is specifically concerned with improving the storage life of the photopolymerizable compositions. ...

In Nature, the polypeptide chains required for the preparation of a target protein are of the same length and composition, having a polydispersity index (PDI) of exactly 1. As protein function arises due to precise chain folding of these monodisperse polypeptides, an important target for polymer chemists is the preparation of monodisperse macromolecules that will minimize structural defects during self-assembly. A range of covalent polymerization methods that approximate to living processes54 have been developed for the preparation of block copolymers, including anionic,55 cationic,56 atom transfer radical polymerization (ATRP),57 reversible addition-fragmentation transfer (RAFT) polymerization,58 nitroxide-mediated radical polymerization59 and ring-opening metathesis polymerization (ROMP).60 The solution self-assembly of such amphiphilic block copolymers is arguably one of the most important methods for the preparation of well-defined and functional nanostructures.61,62 Above the critical ...

The authors report a photochemically controlled ATRP polymerization of MMA. The polymerization is copper catalyzed, uses visible light wavelengths, and results in living polymerizations with low (~1.1) PDI ...

a) a method in which a monomer mixture is allowed to undergone polymerization reaction with a suspension polymerization method, an emulsification polymerization method, a seed polymerization method or a dispersion polymerization method, to thereby produce a dispersion liquid of resin particles; (b) a method in which a monomer mixture is allowed to undergone polymerization, and the obtained resin is then pulverized using a fine pulverizer of, for example, mechanically rotating type or jetting type, followed by classifying, to thereby produce resin particles; (c) a method in which a monomer mixture is allowed to undergone polymerization, and the obtained resin is then dissolved in a solvent, followed by spraying of the resultant resin solution, to thereby produce resin particles; (d) a method in which a monomer mixture is allowed to undergone polymerization, the obtained resin is dissolved in a solvent, another solvent is added to the resultant resin solution to precipitate resin particles, and ...

As part of the design of the modification of nanoporous platforms with polymer brushes, PMAA brushes were grafted from flat silicon surfaces using surface-initiated atom transfer radical polymerization (SI-ATRP).. Chapter 4 describes growth kinetics of the pH-responsive polymer layers were investigated in mixtures of water and methanol with different ratios. The pH-induced swelling and collapse of the brush were characterized by in situ ellipsometry, and showed a fast and reversible switching of the PMAA layers with swelling factors that increased by decreasing the methanol content of the atom transfer radical polymerization mixture. Fourier transform infrared (FTIR) spectra recorded in titration experiments indicated that the effective pKa of the PMAA films were shifted to the value of 6.5 ± 0.2 from the bulk pKa value of PMAA. The shift is due to ion confinement effects in the dense brush, and brings the conformational switching of PMAA brushes closer to physiological conditions. This is ...

A world-leader in the development, manufacturing and commercialization of polymers via atom transfer radical polymerization (ATRP), a revolutionary process for designing and building highly-engineered intelligent ingredients that improve products used in the oilfield chemicals and cosmetic markets. ...

Increasing evidence shows that sex hormones exert a protective effect on the vasculature, especially in the regulation of the active vasomotor responses. However, whether sex hormones affect vascular remodelling is currently unclear. In the present study, we tested the hypothesis that testosterone in males and β-oestradiol in females prevent inward remodelling, possibly through inhibition of cross-linking activity induced by enzymes of the TG (transglutaminase) family. Small mesenteric arteries were isolated from male and female Wistar rats. Dose-dependent relaxation to testosterone and β-oestradiol was inhibited by the NO synthase inhibitor L-NAME (NG-nitro-L-arginine methyl ester), confirming that these hormones induce NO release. When arteries were cannulated, pressurized and kept in organ culture with ET-1 (endothelin-1) for 3 days we observed strong vasoconstriction and inward remodelling. Remodelling was significantly inhibited by testosterone in males, and by β-oestradiol in females. ...

Novel photopolymerizable recording materials suitable in particular for producing photoresist layers and lithographic printing plates are composed of one or more photopolymerizable, olefinically unsaturated organic compounds, optionally a polymeric binder, a photopolymerization initiator, a color-forming system composed of a color former and a photooxidant, a certain benzotriazole compound as a sensitizer and optionally further additive and/or auxiliary substances.

The importance of finding new applications for cellulose‐based products has increased, especially to meet the demand for new environmentally friendly materials, but also since the digitalization of our society will eventually decrease the need for paper. To expand the application area of cellulose, modification to improve and/or introduce new properties can be a requisite. Thus, the focus of this study has been to achieve fundamental knowledge about polymer grafting of cellulose via well‐controlled radical polymerization.. Cellulose, in the form of filter paper, has successfully been grafted via activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) of the monomers: methyl methacrylate, styrene, and glycidyl methacrylate. The advantages of ARGET ATRP are that only a small amount of a copper catalyst is required and the reaction can be performed in limited amount of air; yet, providing for relatively well‐controlled reactions. These benefits can render ...

Bis-boron-thexyl-silaboracycle was prepared by hydroboration of 1,4-bis(methyldivinylsilyl)butane with thexylborane and used to initiate the polyhomologation of dimethylsulfoxonium methylide to afford well-defined hydroxy-terminated 4-arm polyethylene (PE) stars. The synthesized PE stars were transformed to (PE-b-PCL)4 starblock copolymers via the ring-opening polymerization of ϵ-caprolactone (CL) initiated by the hydroxyl end groups of (PE-OH)4 in the presence of P2-tBu phosphazene base. Esterification of the hydroxyl groups of the OH-terminated PE star with 2,2-dichloroacetyl chloride led to (PE-Cl2)4 which was used as initiator (eight initiating atom transfer radical polymerization, ATRP, sites) for the synthesis of (PE-b-PMMA2)4 dendrimer-like stars by the ATRP of methyl methacrylate (MMA). All intermediates and final products were characterized by high temperature gel permeation chromatography and proton nuclear magnetic resonance spectroscopy. © 2016 The Royal Society of Chemistry. ...

In this work, an investigation concerning differences between covalent and physical attachment of poly(ε-caprolactone) (PCL) to a nanocellulose modell surface was conducted. For the covalent attachment, ring-opening polymerization (ROP) was performed using the grafting-from approach, building the polymer from the surface. For the physical attachment, a block copolymer consisting of PCL and poly(di(methylamino)ethyl methacrylate) (PDMAEMA) was made combining ROP and atom transfer radical polymerization (ATRP). The PDMAEMA-part was then quaternized, which resulted in a charged chain - a polyelectrolyte. The charges allow for the PDMAEMA-PCL copolymer to be adsorbed onto the nanocellulose modell surface. The length of the PDMAEMA-part was kept constant (DP=20), and the length of PCL was varied (DP=150, 300, 600) for both the covalently attached polymer and for the copolymer. Finally, differences between the two approaches were evaluated regarding for example surface coverage and ...

This book is the first volume in a two-volume compilation on controlled/living radical polymerization. It combines all important aspects of controlled radical polymerization: from synthetic procedures, to rational selection of reaction components, to understanding of the reaction mechanisms, to materials and applications.This book is focused on recent progress in the rapidly developing field of controlled/living radical polymerization.

Polymerization rates were proportional to initial Sn(Oct)(2) concentration at low [Sn(Oct)(2)](0)/[PrOH](0) values, but began to level off at higher values. When [Sn(Oct)(2)](0)/[PrOH](0) was significantly greater than unity, the opposite behavior occurred. Tin(H) alkoxide concentration became limited by the initial PrOH concentration and independent of initial Sn(Oct)(2) concentration. Addition of 2-ethylhexanoic acid caused polymerization rate retardation, without affecting molecular weight. A control polymerization was conducted in the absence of PrOH. The molecular weight of the resulting polymer was consistent with the measured water content (3.7 wt % by Karl Fisher titration) of the as-received Sn(Oct)(2). The polymerization rate in the absence of PrOH was slow, and this suggested that water is less efficient than an alcohol in creating polymerization-active stannyl ether bonds. (C) 2004 Wiley Periodicals, Inc.

A photopolymerizable composition, element and method of photopolymerizing the composition or element are disclosed wherein the composition comprises an addition polymerizable compound containing ethylenic unsaturation and a co-initiator including a photopolymerization activator and a photosensitizer. In one aspect of the invention, the photosensitizer is selected to be a coumarin having an absorption maximum between about 250 and about 550 nm, and a ##STR1## substituent in the 3-position wherein R1 is alkyl or alkenyl having 1-12 carbon atoms, or a carbocyclic or heterocyclic group having 5-20 nuclear carbon and hetero atoms, the coumarin and the activator being present in an amount sufficient to provide, when the composition is coated, dried and exposed to a medium-pressure mercury light source, a speed which is at least about one-fifth that of the same composition coated, dried and exposed identically except with a co-initiator consisting of Michlers ketone and benzophenone. In another aspect of the

A photopolymerizable composition, element and method of photopolymerizing the composition or element are disclosed wherein the composition comprises an addition polymerizable compound containing ethylenic unsaturation and a co-initiator including a photopolymerization activator and a photosensitizer. In one aspect of the invention, the photosensitizer is selected to be a coumarin having an absorption maximum between about 250 and about 550 nm, and a ##STR1## substituent in the 3-position wherein R1 is alkyl or alkenyl having 1-12 carbon atoms, or a carbocyclic or heterocyclic group having 5-20 nuclear carbon and hetero atoms, the coumarin and the activator being present in an amount sufficient to provide, when the composition is coated, dried and exposed to a medium-pressure mercury light source, a speed which is at least about one-fifth that of the same composition coated, dried and exposed identically except with a co-initiator consisting of Michlers ketone and benzophenone. In another aspect of the

AB amphiphilic comb-like block copolymers of poly(oligo[ethylene glycol] methyl ether methacrylate) and polydimethylsiloxane were synthesised with a methodology based on atom transfer radical polymerization (ATRP). The anionic ring opening polymerisation of hexamethylcyclotrisiloxane followed by reaction with 3-(chlorodimethylsilyl) propyl 2-bromo-2-methylpropanoate propyldimethylchlorosilane gave suitable macroinitiators for the ATRP of oligo[ethylene glycol] methyl ether methacrylate. The latter synthetic procedure was optimised by performing a number of syntheses varying the reaction solvent, catalytic complex and the temperature used. Copolymers with relatively high polydispersity indices (Mw/Mn,1.3) could be synthesised at room temperature by employing a Cu(I)Br:N,N,N′,N′,N″-pentamethyldiethylenetriamine complex in n-propanol with Cu(II)Br. The optimum reaction conditions employed a Cu(I)Cl:N-(n-propyl)-2-pyridyl(methanimine) complex with an n-propanol/water mixture or toluene as ...

Compositions are provided that include a photoinitiator system for free radical polymerization reactions. More specifically, the photoinitiator includes an arylsulfinate ion and a triarylsulfonium ion. Polymerization methods are also provided those include the photoinitiator in a photopolymerizable composition. Additionally, triarylsulfonium arylsulfinate salts are disclosed.

Poly(acrylic acid) (PAA) was attached on both termini of Pluronic P85 copolymer (EO27PO39EO27)) via atom transfer radical polymerization (ATRP) to produce a novel block copolymer, PAA-b-P85-b-PAA (P85PAA). The P85PAA-DOX complex formation and drug loading were strongly dependent on the PAA segment and pH, where the protonation of the carboxyl groups in the PAA segment at pH,7.2 reduced the binding sites of DOX onto P85PAA chains, resulting less DOX uptake at low pH. The composition of the copolymer-DOX complexes that at pH 7.2 was close to the stoichiometric (1:1 mol Dox:carboxyl ratio), indicating the dominance of the electrostatic interactions between cationic DOX molecules and carboxyl groups. DOX loading at pH 5.0 reduced to 0.6:1 molar ratio of DOX:carboxyl indicated that protonation of the carboxyl reduced the DOX binding to the P85PAA block copolymer. DOX release from the complex is highly pH-responsive process, where 57% of encapsulated DOX was released in 30h at pH7.2, and the ...

A. Szabó, Wacha, A., Thomann, R., Szarka, G., Bóta, A., and Iván, B., Synthesis of poly(methyl methacrylate)-poly(poly(ethylene glycol) methacrylate)-polyisobutylene ABCBA pentablock copolymers by combining quasiliving carbocationic and atom transfer radical polymerizations and characterization thereof, Journal of Macromolecular Science, Part A: Pure and Applied Chemistry, vol. 52, no. 4, pp. 252 - 259, 2015. ...

A. Szabó, Wacha, A., Thomann, R., Szarka, G., Bóta, A., and Iván, B., Synthesis of poly(methyl methacrylate)-poly(poly(ethylene glycol) methacrylate)-polyisobutylene ABCBA pentablock copolymers by combining quasiliving carbocationic and atom transfer radical polymerizations and characterization thereof, Journal of Macromolecular Science, Part A: Pure and Applied Chemistry, vol. 52, no. 4, pp. 252 - 259, 2015. ...

A. Szabó, Wacha, A., Thomann, R., Szarka, G., Bóta, A., and Iván, B., Synthesis of poly(methyl methacrylate)-poly(poly(ethylene glycol) methacrylate)-polyisobutylene ABCBA pentablock copolymers by combining quasiliving carbocationic and atom transfer radical polymerizations and characterization thereof, Journal of Macromolecular Science, Part A: Pure and Applied Chemistry, vol. 52, no. 4, pp. 252 - 259, 2015. ...

A. Szabó, Wacha, A., Thomann, R., Szarka, G., Bóta, A., and Iván, B., Synthesis of poly(methyl methacrylate)-poly(poly(ethylene glycol) methacrylate)-polyisobutylene ABCBA pentablock copolymers by combining quasiliving carbocationic and atom transfer radical polymerizations and characterization thereof, Journal of Macromolecular Science, Part A: Pure and Applied Chemistry, vol. 52, no. 4, pp. 252 - 259, 2015. ...

Homogeneous polymerization catalysts require large amounts of solvent and cannot control the polymer morphology. In order to solve this issue, a narrow-shaped spherical ZSM-5 zeolite was used in ethylene polymerization as a support for zirconocene (Cp2ZrCl2). Several heterogeneous catalytic precursors were prepared and used in ethylene polymerization reactions, which showed yields (between 980-8019 kg PE mol-1 h-1) and were efficient at promoting morphological replication of the support. So, a well-established protocol for slurry polymerization reaction was found, yielding well-defined polymer particles in an advantageous polymerization process ...

External and reversible control of the size and surface energy of the pores in mesoporous architectures has been achieved. The method involves modification of mesoporous silica by atom transfer radical polymerization of N-isopropyl acrylamide (the precursor to a stimuli-responsive polymer). The resulting polymer-grafted particles allow the adsorption and transport of molecular species to be dynamically controlled as illustrated in the Figure for the release of rhodamine 6G from the particles at 50degreesC ...

Organic superbases reacted with alkyl iodides (R-I) to reversibly generate the corresponding alkyl radicals (R•). Via this reaction, organic superbases were utilized as new and highly efficient organic catalysts in living radical polymerization. The superbase catalysts included guanidines, aminophosphines and phosphazenes. Low-polydispersity polymers (Mw/Mn = 1.1-1.4) were obtained up to high conversions (e.g., 80%) in reasonably short times (3-12 h) at mild temperatures (60-80 °C) for methyl methacrylate, styrene and several functional methacrylates. The high polymerization rate and good monomer versatility are attractive features of these superbase catalysts.

TY - JOUR. T1 - Insights into the initiation process of enzymatic ring-opening polymerization from monofunctional alcohols using liquid chromatography under critical conditions. AU - Geus, de, M.. AU - Peters, Ron. AU - Koning, C.E.. AU - Heise, A.. PY - 2008. Y1 - 2008. N2 - No abstract. AB - No abstract. U2 - 10.1021/bm701158y. DO - 10.1021/bm701158y. M3 - Article. C2 - 18189361. VL - 9. SP - 752. EP - 757. JO - Biomacromolecules. JF - Biomacromolecules. SN - 1525-7797. IS - 2. ER - ...

In the present invention, the amount of the polyfunctional initiator added (or the total amount of the polyfunctional initiator and the monofunctional initiator in the case where the monofunctional initiator is also used) is from 0.001 to 5 parts by weight per 100 parts by weight of the vinyl monomers described above. If the amount thereof added is below 0.001 part by weight, a relatively large proportion of the monomer is apt to remain unpolymerized, so that the resulting product not only emits the odor of the monomer, but has a low cohesive force. On the other hand, if the amount of the photopolymerization initiator exceeds 5 parts by weight, the odor of the decomposed photopolymerization initiator becomes severe and the performance of the resulting products become poor, resulting in disadvantage in cost, although the polymerization reaction can be sufficiently completed. Therefore, the amount of the photopolymerization initiator added is fixed, depending upon the desired molecular weight of ...

Yes, this is expected.. With higher temperature, there is a larger concentration of radicals in the polymerization mixture, and initially the polymerization goes faster than at lower temperatures. This leads to a faster increase in viscosity, which slows the ability of molecules to diffuse in solution. This means it is more difficult for unreacted monomer to find growing radicals, and for unreacted initiator to find monomer. Radicals are highly reactive so when they cant react the have a habit of engaging in termination reactions which are nonproductive regarding conversion.. This is normally called autoacceleration, and is fairly well described in Odians Principles of Polymerization. Generally, you do not need to heat radical polymerizations beyond the bare minimum to decompose your thermal initiator.. ...

Photopolymerizable compositions are described containing a polymerizable ethylenically unsaturated monomer, a photoinitiator or initiator system, and selected acidic polymeric binders. The organic binder mixture contains a compound chosen from each of two selected classes. These photopolymerizable compositions yield superior processability, i.e., on developing and stripping, in solely aqueous alkaline media devoid of organic solvents, decreased softness and/or tackiness, and improved adhesion when compared to the prior art. The compositions are particularly useful for preparing photoresists.

polymerization by free radical polymerization polystyrene (PS) and PMMA amide functionalized were produced. It is sold under the trademarks Plexiglas, Lucite, and Perspex. Two syntheses are described, involving either free radical or anionic polymerization. Herein, the effect of different post-pressing times and pressure in two cycles of polymerization on the degree of conversion (DC) of thermally activated acrylic resin (TRRA) is analyzed to optimize the polymerization of this material. Experiments of ultrasound used for synthesis of other types of polymers could be indirect reference for the study in this thesis, while ultrasound used for PMMA synthesis could be direct Users are The Tg values of commercial grades of PMMA range from 85 to 165 °C (185 to 329 °F); the range is so wide because of the vast number of commercial compositions which are copolymers with co … Fig. Degree of polymerization. The molecular weight of a repeating unit, Mo= (12 x 2 + 1 x 4) g/ mol = 28 g/mol. Please note: ...

TY - JOUR. T1 - Automated parallel investigations of polymerization kinetics by online monitoring of GC and GPC. AU - Hoogenboom, R.. AU - Fijten, M.W.M.. AU - Abeln, C.H.. AU - Schubert, U.S.. PY - 2004. Y1 - 2004. N2 - Gel permeation chromatog. (GPC) and gas chromatog. (GC) were successfully introduced into a high-throughput workflow for the online monitoring of polymn. kinetics. The feasibility and limitations of online GPC equipped with a high-speed column was evaluated by measuring poly(styrene) stds. and comparison of the results with regular offline GPC measurements. The reliability of the online GC characterization was studied by monitoring the cationic ring-opening-polymn. of 2-ethyl-2-oxazoline, whereby polymn. kinetics were detd. with both online and offline GC. AB - Gel permeation chromatog. (GPC) and gas chromatog. (GC) were successfully introduced into a high-throughput workflow for the online monitoring of polymn. kinetics. The feasibility and limitations of online GPC equipped ...

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PURPOSE:To improve the sensitivity of the composition to a visible ray by incorporating a specified iron allene complex, 3-substd. cumarine compd. and/or a pyridine derivative or its salt in the titled composition. CONSTITUTION:The titled composition comprises the iron allene complex which is composed of at least one kind of a nongaseous ethylenic unsatd. compd. at a room temp. and is shown by formula I, the 3-subst. cumarine compd. shown by formula II and/or the pyridine derivative or its salt shown by formula III. In the formulas I and II, R is hydrogen atom or alkoxy group, etc., X is BF4 or PF6, etc., R1-R4 are each hydrogen atom or alkyl group, etc., X is aryl or a heterocyclic ring group, etc., R5 is alkyl group, etc. In formula III, R1 and R2 are each 1-6C alkyl group, A is aryl group condensed with a pyridine ring. Thus, as the titled composition has the high sensitivity against the visible ray, the exposure light source with the low energy can be used, and great numbers of master plates

Imperfections in the surface of information carrying discs, such as video discs, are avoided by an improved process of manufacture. A bead of photopolymerizable mass is moved between two surfaces, one of which is a patterned surface and the other is a surface to which the photopolymerizable mass will bond upon polymerizing. By moving the liquid mass across the patterned surface, air within the pattern is removed by the leading edge of the bead, reducing imperfections.

TY - JOUR. T1 - Conformal barrier by interfacial polymerization in contact with cells and tissue. AU - Sawhney, A. S.. AU - Pathak, C. P.. AU - Cox, P. R.. AU - Hubbell, J. A.. PY - 1993/12/1. Y1 - 1993/12/1. N2 - We have previously described the rapid photopolymerization of water soluble polyethylene glycol based macromers using visible lasers in contact with tissue and cells. These polymerizations proceed throughout the bulk of the macromer solution. Here we describe a technique whereby this polymerization can be directly initiated form the tissue or cell surface itself and be confined to the interface between the polymerizing from and the bulk macromer solution. The effect of various treatments on the viability of HFF cells are summarized. In evaluating the effect of photopolymerization on cell viability, the objective was to compare the interfacial scheme of photopolymerization to the scheme in which the dye was present in the bulk. The interfacial approach was seen to have some but not a ...

Three brønsted acidic ionic liquids, 1-methylimidazolium acetate ([Hmim][CH3COO]), 1-methylimidazolium propionate ([Hmim][CH3CH2COO]) and 1-methylimidazolium butyrate ([Hmim][CH3CH2CH2COO]) were used as reaction medium for atom transfer radical polymerization of methyl methacrylate with ethyl 2-bromoisobutyrate (EBiB)/CuBr as the initiating system. Kinetic studies, chain extension and block copolymerization confirmed the well-controlled manner of these polymerizations in three brønsted acidic ionic liquids. The reactions were fast and the polydispersities of the polymers were quite narrow (1.10,Mw/Mn,1.34). The rate of polymerization in [Hmim][RCOO] decreased with the increasing alkyl chain lengths (n from 1 to 3), indicating a strong dependence of reaction rate on the length of the substituted groups of the anions in ionic liquids. ...

Strem offers a range of RAFT Agents (Reversible Additional-Fragmentation chain Transfer) for research purposes only under licence from CSIRO.

Atom transfer radical polymerization (ATRP) is an example of a reversible-deactivation radical polymerization. Like its counterpart, ATRA or atom transfer radical addition, it is a means of forming a carbon-carbon bond through a transition metal catalyst. The polymerization from this method is called Atom transfer radical addition polymerization (ATRAP). As the name implies, the atom transfer step is the key step in the reaction responsible for uniform polymer chain growth. ATRP (or transition metal-mediated living radical polymerization) was independently discovered by Mitsuo Sawamoto and by Jin-Shan Wang and Krzysztof Matyjaszewski in 1995. The following scheme presents a typical ATRP reaction: IUPAC definition for ATRP Controlled reversible-deactivation radical polymerization in which the deactivation of the radicals involves reversible atom transfer or reversible group transfer catalyzed usually, though not exclusively, by transition-metal complexes. ATRP usually employs a transition metal ...

The Polymer Division of the Royal Australian Chemical Institute in association with the Australian Academy of Technological Sciences and Engineering has established a prestigious lecture series to promote polymer science and engineering in Australia which are known as the Solomon Lectures, in honour of Prof. David Solomon. These lectures are given by an eminent polymer scientist, and are held at various locations throughout Australasia Presenter: Professor Krzysztof Matyjaszewski, Carnegie Mellon University, Pittsburgh, USA Title: Atom Transfer Radical Polymerization‐ from Mechanism and Synthesis to Materials and Applications Date: Tuesday 23 October, 2012 Time: 11:00am Venue: AIBN Seminar Room - Level 1 ABSTRACT: Copper‐based ATRP (atom transfer radical polymerization) catalytic systems with polydentate nitrogenbased ligands is among most efficient controlled/living radical polymerization systems. Recently, by mechanistic understanding of ATRP, new initiating/catalytic systems were ...

The ethanolic reversible addition-fragmentation chain transfer dispersion polymerization (RAFTDP), at 21 wt-%, of 2-(naphthalen-2-yloxy)ethyl methacrylate (NOEMA) and 2-phenoxyethyl methacrylate (POEMA) with a poly[2- (dimethylamino)ethyl methacrylate] macro-chain transfer agent (CTA) with an average degree of polymerization of 20 (PDMAEMA20) is described. DMAEMA20-b-NOEMAy (y¼20-125) block copolymers were readily prepared under dispersion conditions in ethanol at 708C. However, the polymerization of NOEMA was not well controlled, with size exclusion chromatograms being distinctly bi or multimodal with measured dispersities (Ð M=Mw/Mn) ≤ 1.69. Though NOEMA copolymerization was not ideal, the resulting series of block copolymers did exhibit the anticipated full spectrum of nanoparticle morphologies (spheres, worms, and vesicles). Interestingly, these morphology transitions occurred over a relatively narrow range of block copolymer compositions. In the case of POEMA, copolymerization was also ...

Until the mid 90s, free radical polymerization (FRP) was characterized by producing polymers with high average molecular weig hts (1×10 5-1×106) since the beginning of polymerization, index of polidispersity (PDI) greater than 1.5 and wide molecular weight distribution (MWD). When necessary to produce polymers with more defined structure, it was usually used anionic polymerization, which is capable to produce polymers with narrow molecular weight distribution and PDI around 1.0 (1.1-1.2). The ionic polymerization, however, needs to be held in a high degree of purity and in the absence of inhibitors, what make the ionic polymerization expensive and not very practical from the industrial point of view. A promising alternative to ionic polymerization has been the living radical polymerization (LFRP), which is much more robust to the impurities and kind of solvent and it is able to produce polymers with polidispersity close to one. Nevertheless, the LFRP presents lower polymerization rates ...

Bovine Serum Albumin (BSA) and lysozyme have been chemically transformed into macroinitiators for the synthesis of fluorescent bioconjugates by living radical polymerization. A new fluorescent monomer based on rhodamine B has been synthesized and incorporated Bovine Serum Albumin (BSA) and lysozyme have been chemically transformed into macroinitiators for the synthesis of fluorescent bioconjugates by living radical polymerization. A new fluorescent monomer based on rhodamine B has been synthesized and incorporated into the polymer backbone of the bioconjugate by copolymerization. This provides a new strategy for the synthesis of fluorescent bioconjugates with improved traceability in biological environments, during biomedical assays. [+] [-] ...

Polymerization-induced self-assembly and re-organization (PISR) was used to prepare polymeric nanostructured materials with a variety of morphologies. Reversible addition-fragmentation chain transfer (RAFT) polymerization of styrene in a selective solvent, methanol, was carried out using cyanoisopropyl dithi

This talk focuses on the use of RAFT chemistry (Reversible Addition-Fragmentation chain Transfer polymerization) under different conditions. In the first section of the talk I will present how RAFT chemistry was employed to modify cellulose and a novel route to improve and tune the physical properties of cellulose. In a second part, I will present the syntheses of a range of glycopolymeric architectures (linear, branched and hyper branched) by a combination of RAFT and click chemistry. Finally, I will show the synthesis and in situ self-assembly of diblock and triblock functional copolymers; as well as the preparation of core-shell organic/inorganic particles using these self-assembled structures.. ...

We present the synthesis and characterization of well-defined polycationic copolymers containing thiazole dyes in the side chain. Atom transfer radical polymerization (ATRP) was used for the copolymerization of 3-azidopropyl methacrylate (AzPMA) and N,N-dimethylaminoethyl methacrylate (DMAEMA) of different composition. Thiazole-based alkyne-functionalized dyes (e.g., 5-methyl-4-(prop-2-yn-1-yloxy)-2-(pyridin-2-yl)thiazole, (MPPT)) were afterwards covalently attached using copper catalyzed azide alkyne cycloadditions (CuAAC) reaching contents of up to 9 mol % dye. Subsequent quaternization of the tertiary nitrogen of DMAEMA with strong methylation agents (e.g., methyl iodide) led to permanently charged polyelectrolytes. The materials were characterized by size exclusion chromatography, as well as NMR- and UV/VIS-spectroscopy. Particular attention is paid to the spectroscopic properties of the dyes in the side chain upon environmental changes such as pH and salinity. We anticipate the application of such

A two-step modification was used to attach atom transfer radical polymerization (ATRP) initiator onto graphene oxide surface. ATRP polymerization of 2-hydr

Since our founding, Chem-Trend has been focused on a better way. If he started a cycle of Tren or Winny and was lucky to put on 10 lbs of solid muscle that would now put him at 210 lbs. Low prices, quantity discounts, free shipping, high delivery success. Density of Common Liquids Table. ws is a leading online source of steroids that offers the highest quality legitimate anabolic steroids since 2004. underconstructionthefilm. every other day weekly dose range. Testosterone is the hormone that allows you to gain muscle mass, strength and endurance. Tren, as it is often called, is both highly androgenic and anabolic. Jul 23, 2017. Manufacturer: Dragon Pharma Substance: Methyltrienolone Package: 100 tabs (250 mcg/tab). Ambient temperature atom transfer radical polymerization (ATRP) of methyl acrylate (MA), methyl methacrylate (MMA) and styrene (Sty) in the presence of polar solvents (dimethyl sulfoxide: DMSO, dimethylformamide: DMF and acetonitrile: MeCN) with a mixed transition metal catalyst ...

The talk will present the synthesis and characterization of a new class of hybrid amphiphilic system between an electrolyte polyacrylic acid (PAA) synthetic segment, and a hydrophobic beta-sheet forming peptide segment, poly(L-valine) (PLVAL). The synthesis of monodispersed copolymers (Mw/Mn , 1.3) was achieved through a combination of atom transfer radical polymerization, click chemistry, and nickel-catalyzed ring opening of N-carboxy anhydrides. The click chemistry is demonstrated to be an excellent method for the intermediate -amino functionalization step to afford macroinitiators that are free from deactivating or interfering molecules with degree of functionality about 90%. Light scattering and circular dichroism characterization of PAAx-block-PLVALy (x-y of 80-100, 80-80, 80-60, and 40-100) show a correlation of the formation of spherical core-shell micelles to the ability of the peptide segment to form ordered beta-sheet structures. Generally, the beta sheet formation is stabilized by a ...

Polymer-coated liposomes, particularly poly(ethylene glycol) (PEG)-substituted liposomes, have emerged as long-circulating carrier systems for drug delivery and diagnostic purposes. A rapid synthesis of three different types of multifunctional lipids with structurally diverse hydrophilic, polyether-based architectures via one- or two-pot approaches is described. Architectural variation is achieved by the combination of different oxyanionic polymerization strategies and various glycidyl ether building units. Branched polyglycerol lipids have been prepared via cholesterol- or 1,2-bis-n-alkyl glyceryl ether-initiated, oxyanionic ring-opening polymerization (ROP) of protected glycidyl ethers and glycidol, respectively. In addition 1:0 these polyglycerol-based lipids, we describe the synthesis of multifunctional PEGs as the hydrophilic part of the lipid, which can be compared to conventional stealth lipids, but bear an adjustable number of hydroxyl functions within the PEG backbone. These lipids can be

摘要】：正Polymers of cyclic esters,such as lactides and lactones,have attracted much attention due to their biodegradable,biocompatible and permeable properties.Ring-opening polymerization(ROP) of cyclic esters initiated by well-defined metal complexes is an effective way to produce polyesters.Among them, ...

Fingerprint Dive into the research topics of Synthesis and end group structure of 2-deoxydextrans prepared via the cationic ring-opening polymerization of an anhydro sugar. Together they form a unique fingerprint. ...

en] The photoinitiated cobalt-mediated radical polymerization enables the synthesis of novel alpha-functional and alpha,omega-telechelic polymers. In combination with ring-opening polymerization, it also produces new amphiphilic copolymers which self-assemble into flower-like vesicles in water ...

The introductory slide from the home page, reproduced below, indicates that Controlled/Living Radical Polymerization (CRP) procedures can be used for the preparation of copolymers incorporating a broad spectrum of radically (co)polymerizable monomers forming materials with predetermined molecular weight, and narrow molecular weight distribution, if desired. The most recent work on conducting an ATRP with low concentration of transition metals indicate that some control over the breadth of the MWD is also possible. Here, and elsewhere in the text the word control and/or controlled means that if the polymerization process conditions are selected so that the contributions of the chain breaking processes are insignificant compared to chain propagation, allowing synthesis of polymers with predetermined molecular weights, low polydispersities and site specific functionalities.. ...

A method is disclosed for the de novo synthesis of polypeptide-containing polymers. This disclosure also includes a description of, and a method for the preparation of, a class of polymerizable compounds used in the synthesis of polypeptide-containing polymers. These polymerizable compounds are chemical conjugates prepared by covalent linkage of polymerizable organic monomers with specific polypeptides. Soluble monomer/polypeptide conjugates can be polymerized in solution with additional nonderivatized organic monomers to form desired polypeptide-containing polymers. The amount and composition of monomer and monomer/polypeptide conjugates can be varied in order to provide control of (a) molecular spacing, steric accessibility, and number of polypeptide molecules that are integrally incorporated into the polymer backbone, and (b) the chemical and physical structure of the polymer itself. This enables the specific tailoring of polypeptide-containing

TY - JOUR. T1 - Enzymatic polymerization catalyzed by surfactant-coated lipases in organic media. AU - Noda, Sadafumi. AU - Kamiya, Noriho. AU - Goto, Masahiro. AU - Nakashio, Fumiyuki. PY - 1997/1/1. Y1 - 1997/1/1. N2 - Structural ring-opening of lactones driven by enzymatic polymerization has been performed using low concentration dosages of surfactant-coated lipases in organic media. By comparison, enzymatic polymerization rate with coated lipase proceeded at a rate 100-fold better than native powder. Similarly a higher polymeric molecular weight (21,300), narrow dispersity (Mw/Mn = 1.9) and better conversion (100%) were obtained following polyesterification tests with surfactant-coated lipase.. AB - Structural ring-opening of lactones driven by enzymatic polymerization has been performed using low concentration dosages of surfactant-coated lipases in organic media. By comparison, enzymatic polymerization rate with coated lipase proceeded at a rate 100-fold better than native powder. ...

The reaction mechanism of living radical polymerization using organic catalysts, a reversible complexation mediated polymerization (RCMP), was studied using both theoretical calculations and experiments. The studied catalysts are tetramethylguanidine (TMG), triethylamine (TEA), and thiophene. Methyl 2-iodoisobutyrate (MMA-I) was used as the low-molar-mass model of the dormant species (alkyl iodide) of poly(methyl methacrylate) iodide (PMMA-I). For the reaction of MMA-I with TEA to generate MMA• and •I-TEA radicals (activation process), the Gibbs activation free energy for the inner-sphere electron transfer mechanism was calculated to be 39.7 kcal mol-1, while the observed one was 25.1 kcal mol-1. This difference of the energies suggests that the present RCMP proceeds via the outer-sphere electron transfer mechanism, i.e., single-electron transfer (SET) reaction from TEA to MMA-I to generate MMA• and •I-TEA radicals. The mechanism of the deactivation process of MMA• to generate MMA-I ...

ARGET and ICAR: As shown in the figure displaying relative catalyst activity for copper based catalysts at the end of the page on Catalyst Development {link} catalysts have been developed that show a broad range of activity. It is possible, therefore, to select an active catalyst and run the reaction with lower levels of catalyst. (26, 27) In the page on Procedures for Initiation of an ATRP Reaction we cover much of the background on the development of this low catalyst concentration ATRP. Indeed with an extension of the concept of AGET ATRP (28, 29) to include continuous regeneration of the transition metal complex throughout the reaction, ARGET ATRP (27-32), it is possible to reduce the level of catalyst below that of natural termination reactions and ATRP can be conducted with ppm levels of catalyst. ARGET ATRP arose when we considered the implications of the convenient procedure for initiating an ATRP system described in AGET ATRP, where the activators are generated by electron transfer ...

TY - JOUR. T1 - Poly(2-vinylpyridine) as a template for the radical polymerization of methcrylic acid; influence of the solvent. AU - Smid, J.. AU - Tan, Y.Y.. AU - Challa, G.. AU - Hagen, W.R.. PY - 1985. Y1 - 1985. M3 - Article. VL - 9. SP - 757. EP - 763. JO - European Polymer Journal. JF - European Polymer Journal. SN - 0014-3057. ER - ...

The knowledge obtained from the microtubule polymerization assays and cell line cytotoxicity assays showed agreement. Paclitaxel was equally the strongest inhibitor of polymerization and the most cytotoxic compound. Tx-A experienced the closest effect to paclitaxel in the polymerization assay, and was also the closest to paclitaxel in the cytotoxicity assays. Tx-C had the up coming strongest influence on polymerization, and was the up coming most cytotoxic. Last but not least, Tx-D and Tx-F have been equally the weakest inhibitors of polymerization and the least cytotoxic compounds. Examining the first premise with regards to the effect of the modifications to paclitaxel on the activity of the taxane derivatives, only the scenario of Tx-C showed assistance. In this scenario we constantly noticed a modest but significant lower in action in comparison to paclitaxel, as at first envisioned. Nevertheless, in the circumstances of the other three derivatives examined, the predicted styles have been ...

4. mamaftmemberc / mamaftmembercpp. PATCH:- 0003-Mama-Mamda-apps-do-not-flush-data-to-log. From 519e59b5d03f4782a6c134db68c4853620e1e13c Mon Sep 17 00:00:00 2001. From: A Ambrose ,[email protected],. Date: Thu, 21 Aug 2014 14:06:51 +0100. Subject: [PATCH 3/3] Mama & Mamda apps do not flush data to log. Modification to the mama & mamda example applications to flush data when logged to file.. All languages, C, C++, C# & Java.. [OMAMA-278/OMAMA-279]. Signed-off-by: A Ambrose ,[email protected],. ---. mama/c_cpp/src/examples/c/mamaftmemberc.c , 3 +++. mama/c_cpp/src/examples/c/mamainboxc.c , 2 ++. mama/c_cpp/src/examples/c/mamaio.c , 2 ++. mama/c_cpp/src/examples/c/mamalistenc.c , 1 +. mama/c_cpp/src/examples/c/mamalistencachedc.c , 1 +. mama/c_cpp/src/examples/c/mamamultisubscriberc.c , 2 ++. mama/c_cpp/src/examples/c/mamaproxyc.c , 2 ++. mama/c_cpp/src/examples/c/mamapublisherc.c , 2 ++. mama/c_cpp/src/examples/c/mamasubscriberc.c , 2 ++. .../src/examples/c/mamasymbollistsubscriberc.c , 1 ...

Actin is the most abundant cytoskeletal protein, accounting for 20% of the total protein content in all eukaryotic cells, especially muscle cells. Actin polymerizes from the globular state known as G-actin monomer to the filamentous semi-flexible polymer, F-actin. This polymerization is involved in cell motility, cell signaling, and even in regulation of ion transport. Actin polymerization is known to be regulated in vivo by more than 150 actin-binding proteins, but was shown early on to be capable of thermodynamic regulation and this finding was proven under conditions of varying salt, ATP, initial monomer concentration and temperature. It was shown that actin polymerization is entropically driven, has a floor temperature for propagation, and is analogous to a second-order phase transition. The purpose of this work was to measure the effect of pressure on the extent of actin polymerization as a function of temperature. The relaxations of the extent of polymerization after temperature jumps ...

The present invention provides a catalyst precursor, a catalyst system comprising the precursor, and a polymerization method using the catalyst system, an embodiment of the precursor is selected from the following structures: wherein T is a bridging group; M is selected from Groups 3 to 13 atoms, and the Lanthanide series of atoms the Periodic Table of the Elements; Z is a coordination ligand; each L is a monovalent, bivalent, or trivalent anionic ligand; X and Y are each independently selected from nitrogen, oxygen, sulfur, and phosphorus; each R can be the same or different and is a bulky substituent that is sterically hindering with respect to X and Y.

The polymerization of scallop p-like actin is significantly slower than that of skeletal muscle alpha-actin. To reveal which steps of polymerization contribute to this difference, we estimated the efficiency of nucleation of the two actins, the rates of filament elongation at spontaneous and gelsolin-nucleated polymerization and the turnover rates of the filament Subunits at steady-state. Scallop actin nucleated nearly twice less efficient than rabbit actin. In actin filaments with free ends, when dynamics at the barbed ends overrides that at the pointed ends, the relative association rate constants of alpha- and beta-actin were similar, whereas the relative dissociation rate constant of beta-ATP-actin subunits was 2- to 3-fold higher than that of alpha-actin. The 2- to 3-fold faster polymerization of skeletal muscle versus scallop Ca-actin was preserved with gelsolin-capped actin filaments when only polymerization at the pointed end is possible. With gelsolin-induced polymerization, the rate ...

BioAssay record AID 214536 submitted by ChEMBL: Tested for the effect on polymerization of the tubulin present by microtubule assembly assay.

Offers new strategies to optimize polymer reactions. With contributions from leading macromolecular scientists and engineers, this book provides a practical guide to polymerization monitoring. It enables laboratory researchers to optimize polymer reactions by providing them with a better understanding of the underlying reaction kinetics and mechanisms. Moreover, it opens the door to improved industrial-scale reactions, including enhanced product quality and reduced harmful emissions.. Monitoring Polymerization Reactions begins with a review of the basic elements of polymer reactions and their kinetics, including an overview of stimuli-responsive polymers. Next, it explains why certain polymer and reaction characteristics need to be monitored. The book then explores a variety of practical topics, including:. ...

Pn mama nie mmg slalu ar kene ketumbit senar nye masa kecik2lah masa tu sekolah rendah , sekolah Menengah x jadi dah ..Kiranya tiap2 dua buln sekali mesti jadi… sampaikan pn mama x nak p sekolah malu beb… Masa tu rasanya macam kita nie pembawa penyakit nak mati je rasa.. Tapi Bonda pn mama garang… kalau bab sekolah nie… mesti pergi… walaupun kadang2 pn mama rasa macam nak pakai purdah je…Sampai masuk dalam Kelas , pn mama tunduk je …al maklumlah Malu… Masalahnya dalam keluarga pn mama , pn mama je yang suka jadi…Kenapa Iyer?????..mybe pn mama banyak dosa kot... kan orang cakap penyakit tu nak hapuskan dosa... ha..ha...ha ...

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The roseate spoonbill is a sociable wading bird from the ibis family. Adults have a bare greenish head and a white neck, back and breast along with a grey bill. They can be seen with a tuft of pink feathers in the center when breeding, but are otherwise a deep pink. Like the American flamingo, their pink color is diet-derived and can range from pale pink to bright magenta, depending on age and location. Unlike herons, spoonbills fly with their necks outstretched. They alternate groups of stiff, shallow wingbeats with glides.. To learn more about the roseate spoonbill… read more.. ...

A process for producing a substantially dry polymer particle powder. A mixture of polymerization reagents is formed from a mixture of at least one monomer source and a solvent selected from the group consisting essentially of water and organic solvents and an initiator source. The mixture of polymerization reagents is sprayed into a heated, controlled atmosphere, forming droplets of the mixture which are allowed to fall through the heated, controlled atmosphere for a sufficient period of time to obtain a desired degree of polymerization. The solvent is continuously evacuated from the atmosphere during the polymerization process.