Polymerization and monomer degradation. Medical search. Frequent questions

Full experimental section containing the description of the materials, characterization methods and syntheses of the obtained polymers, spectroscopic data ( 1 H, 13 C and IR), 1 H NMR kinetics, UV-vis measurements, polymerization analytics to determine the chain transfer constant, SEC curves of the RAFT initiated (co)polymers, the determination of the copolymerization parameters Q and e values and force constant. (beilstein-journals.org)
Dusselier, M. Syntheses and chemical transformations of glycolide and lactide as monomers for biodegradable polymers. (beilstein-journals.org)
The polymers were prepared by polymerisation of metal acrylate monomer and neutralisation of poly(acrylic acid) by the appropriate metal salt. (gla.ac.uk)
The second section of the work involved the thermal degradation of these polymers and copolymers. (gla.ac.uk)
The techniques used to study the thermal degradation of the polymers were thermogravimetry (TG), differential thermal analysis (DTA) direct scanning calorimetry (DSC) and thermal volatilistaion analysis (TVA), with fractionation of the products of degradation by sub-ambient TVA. (gla.ac.uk)
Cu. The polymers made by neutralisation of poly(acrylic acid) and those made by polymerisation of metal acrylate monomer exhibited similar thermal stability and degradation characteristics. (gla.ac.uk)
We identified two discrete regions of FtsZ important for degradation of both FtsZ monomers and polymers by ClpXP in vitro. (uri.edu)
The inhibitor reacts with monomers before they can form insoluble polymers. (turbomachinerymag.com)
Super absorbent polymers utilized in agriculture are typically arranged from acrylic acids and a cross-connecting agent like potassium by solution or suspension polymerization. (prlog.org)
Thermal properties of thermoplastic polymers: influence of polymer structure and procedure of radical polymerization. (mpg.de)
The research team, led by E. Ihara and H. Shimomoto, has been utilizing unique reactivities of a diazocarbonyl group for polymer synthesis where they have succeeded in preparing a variety of polymers with unprecedented chemical structures by the polymerization of some bis(diazocarbonyl) compounds bearing two diazocarbonyl groups in one molecule. (eurekalert.org)
In acrylic resin materials, polymerization, which is the conversion of monomers into polymers, is usually incomplete. (ac.ir)
He developed a general procedure for free radical-ring opening polymerization that uniquely incorporates hydrophilic units in the backbone, thus providing a general route to preparation of biocompatible addition polymers. (nae.edu)
He carried out pioneering studies on the pyrolysis of organic and polymeric materials leading to (1) a general preparative route for sensitive olefins by rapid heating of esters and (2) the first interpretation of thermal degradation of vinyl polymers via a unique cyclic mechanism. (nae.edu)
However, due to the use of conventional radical polymerization, the resulting copolymers have generally been limited to nondegradable vinyl polymers. (researcher-app.com)
The higher conversion and lower water sorption presented by BisEMA co-polymers resulted in greater resistance to degradation in ethanol compared with BisGMA-based materials. (elsevierpure.com)

The work carried out in this study has involved the preparation, characterisation and subsequent thermal degradation of homopolymers and copolymers with structures based on metal salts of acrylic acid. (gla.ac.uk)
The thermal degradation experiments were carried out either by ramped programmed or isothermal heating in oxygen free environments. (gla.ac.uk)
The thermal degradation of transition metal salts of poly(acrylic acid) occurred by a free radical decomposition process. (gla.ac.uk)
The thermal degradation of the three copolymers of acrylic acid with styrene and the zinc salts of these copolymers occurred by a free radical mechanism. (gla.ac.uk)
The zinc salt copolymers showed a slight increase in thermal stability compared to the acid copolymer In isothermal heating experiments the rate of degradation of the acid copolymers was decreased by converting them to their zinc salts. (gla.ac.uk)
On the basis of its superior thermal degradation and hydrolysis, PLLA has potential as a feedstock recycling material ideally suited to a future sustainable society. (hindawi.com)
Fouling is caused mainly by three different mechanisms: free radical polymerization, condensation and thermal degradation to coke. (turbomachinerymag.com)
Thermal characteristics, and degradation products of electrochemically prepared poly(paraphenylene vinylene). (metu.edu.tr)
Degradation may be affected by thermal or radiation induced processes, where the backbone carbon-carbon bond is broken to form an active free radical. (com.vn)
In such thermal or radiation-induced degradation processes, there is a random distribution of varying chain lengths, and some small percent of the molecules may be 8 carbons long. (com.vn)
Regalrez® 1094 is especially suited to applications where the lowest color and most stability against weathering and thermal degradation is required. (naturalpigments.eu)
Thermal and crystallographic characterizations revealed that even the very high molecular weight PLA copolymers crystallized in a stereocomplex phase, and that their degradation temperature was as high as 354 °C. (tau.ac.il)
Polymerisation of this monomer forms poly(dihydroferulic acid), PHFA, which mimics the structure and thermal properties of PET. (rsc.org)

Aim: To evaluate the long-term bond strength, degree of conversion and resistance to degradation in ethanol of HEMA-containing and HEMA-free model adhesive resins of a three-step etch-andrinse adhesive system. (bvsalud.org)
Conclusions: HEMA content of the adhesive resin did not influence the bond strength to dentin, degree of conversion or resistance to degradation in ethanol. (bvsalud.org)

Improvement of the adhesive systems has been associated with the development of different system formulations, as the incorporation of resin monomers with hydrophilic groups increases the bond strength 4 . (bvsalud.org)
However, is essential for successful bonding using etch-and- rinse the permeation of resin monomers within exposed collagen adhesives, it also affects the long-term bonding stability9,10. (bvsalud.org)

Mechanisms of polymer degradation are discussed with respect to the degradation products obtained during TVA. (gla.ac.uk)
New Polymerizations and New Monomers (Polymerizations via Mechanisms not Included in the Preceding Classifications 1-4, New Catalysts, Novel Monomers, etc. (or.jp)
Investigation of living radical polymerisation mechanisms by advanced fractionation methods. (sun.ac.za)

Almost all commercial etch-and-rinse adhesive systems include 2- hydroxyethyl methacrylate (HEMA) or other hydrophilic monomer in their composition 5 . (bvsalud.org)
This hydrophilic monomer is required to enhance infiltration of hydrophobic components into demineralized dentin to promote micromechanical retention of curable monomers. (bvsalud.org)
However, the presence of hydrophilic components in the hybrid layer could promote water penetration and degradation of the polymer over time 6-8 whereas HEMA increases permeability of the adhesive layer, taking up water and decreasing the mechanical properties of hybrid layer. (bvsalud.org)
However, more studies are needed to evaluate other properties and the longevity of the adhesive/dentin bond of adhesive resins with or without HEMA, since the presence of a hydrophilic monomer in the adhesive layer could influence the bond strength over time. (bvsalud.org)
Recently, developed resin adhesives contain more acidic hydrophilic monomers, and higher amounts of water to improve monomer impregnation into wet dentin substrate, resulting in lower degrees of polymerization of adhesive resin. (sciepub.com)

Polyethylene waxes produced by means of degradation or recovery from polyethylene resin streams contain very low molecular weight materials that must be removed to prevent volatilization and potential fire hazards during use. (wikipedia.org)
Polymerization occurs when two or more unsaturated monomers with reactive double bonds (or consisting of the same elements in the same proportions by weight but differing in molecular weight) react to form another compound having higher molecular weight and different physical properties. (turbomachinerymag.com)
Molecular imprinting is a process in which functional and crosslinking monomers are co-polymerized in the presence of the target analyte, the imprint molecule. (intechopen.com)
evolution of HCN, monomer, low molecular weight oligomers due to random chain cleavages a. (metu.edu.tr)
PTFE resin is made by the polymerization of TFE (tetrafluoroethylene monomer) to very high molecular weight (MW), in the millions. (com.vn)
The polymerization catalyzed by a Rh catalyst proceeded as they expected, affording poly(β-keto enol ether) with a molecular weight higher than 10000. (eurekalert.org)
In addition, materials made of the polymer can be easily degraded to the above-described low molecular weight compounds, including one of the monomers, after they are used in neutral conditions. (eurekalert.org)
200 kDa, as well as stereo-n-block copolymers (n = tri, tetra) with high molecular weights by sequential monomer addition. (tau.ac.il)

Punyodom, W. Novel Poly(Methylenelactide-g-L-Lactide) Graft Copolymers Synthesized by a Combination of Vinyl Addition and Ring-Opening Polymerizations. (beilstein-journals.org)
Blends of poly(L-lactic acid) (PLLA) and polypropylene (PP), which are candidates for the practical use of PLLA, were investigated for selective degradation of PLLA, resulting in quantitative conversion of PLLA components into cyclic monomers, lactides, using magnesium oxide (MgO) as a depolymerization catalyst. (hindawi.com)
Here, the water-soluble nucleoside reverse transcriptase inhibitor emtricitabine (FTC) has been used as a novel A-B monomer in step-growth polymerisation with chloroformate functional C n monomers, to produce new poly(carbamate/carbonate) structures with varying architecture. (johnshopkins.edu)

Polymer Degradation and Stability 2021, 183, 109427. (beilstein-journals.org)

Recycled plastics are low-value commodities due to residual impurities and the degradation of polymer properties with each cycle of re-use. (nature.com)
The incomplete polymerization, especially in auto-polymerized types (3), results in a gradual release of the residual monomers, even in dry static environments. (ac.ir)
Most previous research has evaluated the effects of modes of polymerization (11), methods of acrylic manipulation (1, 3, 6, 12), procedures of polishing (3, 6), and times of water immersion (11, 13) on the amount of residual MMA. (ac.ir)

Lignin-based polymeric surfactants for emulsion polymerization. (mpg.de)
Miller and co-workers combined acetic anhydride with vanillin - a by-product in the manufacture of paper from lignin - to form the monomer acetyldihydroferulic acid. (rsc.org)
Sustainable functional materials from lignin: Oxidative depolymerisation, monomer synthesis and polymerisation. (sun.ac.za)

Initially, the functional monomer forms a complex and, after polymerization, their functional groups are held by the highly crosslinking polymeric structure. (intechopen.com)
This dual behavior allows expanding the portfolio of functional intermediates and monomers derived from a CO 2 -derived heterocycle. (iciq.org)
In the third project (Chapter 4), a diverse series of functional bicyclic monomers is investigated for their propensity for ROP in the presence of TBD as catalyst and benzyl alcohol (BnOH) as initiator. (iciq.org)

Typically, PLLA is being produced via starch saccharification, lactic acid fermentation, oligomerization, cyclic monomer formation, and ring-opening polymerization of the cyclic monomer. (hindawi.com)
The oligomerization of vinyl monomers has been studied to understand the stereochemistry of polymerization and termination reactions. (baumaschinen-knell.de)

In future, Miller's team plan to investigate the long-term degradation characteristics of PHFA as well as performing scale-up fabrication studies to compare the biorenewable polymer with PET in different forms, such as a cup, plate or water bottle. (rsc.org)

The anti-oxidant reduces oxidative polymerization. (turbomachinerymag.com)

Here, we show that next-generation plastics-polymerized using dynamic covalent diketoenamine bonds-allow the recovery of monomers from common additives, even in mixed waste streams. (nature.com)

The fibrin monomer, which is insoluble, aggregates spontaneously into fibrin polymer. (medscape.com)

Now they have found that three-component polymerization of an appropriated combination of a bis(diazocarbonyl) compound, bis(1,3-diketone), and tetrahydrofuran (THF) as monomers yields a new type of polymer structure containing the β-keto enol ether framework in the main chain, which has been known to be readily cleaved with a small amount of acid. (eurekalert.org)

Chain-extension with styrene afforded well-defined P(MPDL- alt -NEtMI)- b -polystyrene copolymers, and degradation of the homopolymers and block copolymers showed complete breakdown of the alternating copolymer. (researcher-app.com)

Polymer is any of a class of synthetic and natural materials collected of very huge molecules, called macromolecules, that are multiples of simpler chemical units known as monomers. (prlog.org)
In theory, after a strict process, there is no difference in the quality of pure MMA monomers and new synthetic monomers. (samtop.com)
Synthetic bio-based elastomers, on the other hand, are derived from bio-based monomers. (pneurama.com)

If the feedstock recycling of PLLA to the cyclic monomer, L,L-lactide, can be achieved more effectively, it will then become possible to renew PLLA by the shortest, most energy-efficient route. (hindawi.com)
Copolymerization of N -ethyl maleimide (NEtMI) with the cyclic ketene acetal (CKA) 2-methylene-4-phenyl-1,3-dioxolane (MPDL) was demonstrated to proceed in an alternating fashion, and controlled polymerization was achieved using reversible addition-fragmentation chain transfer (RAFT) polymerization. (researcher-app.com)

Radical copolymerization of donor-acceptor (D-A) monomer pairs has served as a versatile platform for the development of alternating copolymers. (researcher-app.com)

By combining radical D-A copolymerization with radical ring-opening polymerization (rROP), we have synthesized an alternating copolymer with a high incorporation of degradable backbone units. (researcher-app.com)

Professor Bailey invented a new class of monomers that expand during polymerization, resulting in high-strength adhesives, strain-free composites, and strongly adhering coatings. (nae.edu)

This theses covers the preparation and the characterization of a rigid hydrogel from N-Vinyl pyrrolidone-methacrylic acid (VP-MAA) monomers and polyethyleneoxide (PEO) polymer. (metu.edu.tr)
The acid-sensitivity of the β-keto enol ether framework of the polymer was so high that the degradation proceeded even in a chloroform solution because the solvent usually contains a very small amount of acid spontaneously generated from the solvent molecule under an ambient condition. (eurekalert.org)

The monomers used were bisphenol A glycol dimethacrylate (BisGMA), ethoxylated bisphenol A glycol dimethacrylate 6 (BisEMA), triethylene glycol dimethacrylate (TEGDMA) and 2-hydroxyethyl methacrylate (HEMA). (bvsalud.org)
This study evaluated the effect of the combination of two dimethacrylate-based monomers [bisphenol A diglycidyl dimethacrylate (BisGMA) or bisphenol A ethoxylated dimethacrylate (BisEMA)] with diluents either derived from ethylene glycol dimethacrylate (ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate) or 1,10-decanediol dimethacrylate (D 3 MA) on network characteristics and mechanical properties of neat resin and composite materials. (elsevierpure.com)
abstract = "This study evaluated the effect of the combination of two dimethacrylate-based monomers [bisphenol A diglycidyl dimethacrylate (BisGMA) or bisphenol A ethoxylated dimethacrylate (BisEMA)] with diluents either derived from ethylene glycol dimethacrylate (ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate) or 1,10-decanediol dimethacrylate (D3MA) on network characteristics and mechanical properties of neat resin and composite materials. (elsevierpure.com)

There are various treatment methods including oxidation processes, biological degradation, membrane filtration and coagulation/flocculation have been studied to treat dyeing wastewater. (intechopen.com)
A direct route to densely substituted macromolecular aliphatic carbonates is developed including bifunctional monomers capable of initiating two distinct ring-opening polymerization processes offering versatile options for polymerization and crosslinking strategies. (iciq.org)

In normal fibrin clot formation, a fibrin monomer forms after thrombin cleaves fibrinopeptide A and B from the alpha and beta chains of the fibrinogen molecule. (medscape.com)
The impairment of fibrinogen, which is synthesized in the liver, is due to a structural defect caused by an increased carbohydrate content that interferes with the polymerization of the fibrin, depending on the degree of abnormality of the fibrinogen molecule. (medscape.com)

Expected effects of homolysis in the blend system were also determined as slight changes in activation energy of degradation for both the components and through the suppression of degradation by an antioxidant. (hindawi.com)

Plastics that undergo reversible polymerization allow high-value monomers to be recovered and re-manufactured into pristine materials, which should incentivize recycling in closed-loop life cycles. (nature.com)
Low MW PTFE micro-powders are typically made by the degradation of such high MW PTFE resin. (com.vn)
However, the purity of the degradation monomer produced by the recovered acrylic is not high. (samtop.com)
The aim is to evaluate the effect of different layer thickness on the amount of elution of monomers from two high viscosity bulk-fill composites after 24 h and 1 month storage in ethanol using high-performance liquid chromatography (HPLC) analysis. (org.in)

The polymerization mechanism showed autoacceleration and the rate of polymerization was higher in the presence of oxygen. (metu.edu.tr)

Efficient adhesive resin infiltration and polymerization at the tooth/resin interface are related to the preservation of the results of clinical procedures 3 . (bvsalud.org)
Hence, the present study tested the null hypothesis that the addition of 15% HEMA in a model adhesive resin will not influence the microshear bond strength, degree of conversion and resistance to chemical degradation. (bvsalud.org)

RAFT polymerization as a scaffold for the synthesis of SNAP-tag labels. (sun.ac.za)

The VP-MAA-PEO hydrogel was obtained by template polymerization which can be defined as a method of polymer synthesis in which specific interactions consists of the preparation of a polymer (daughter polymer) in the presence of a m. (metu.edu.tr)

The recycled acrylic uses recycled acrylic scrap, which is thermally degraded to obtain a regenerated MMA (methyl methacrylate) monomer. (samtop.com)
The literature includes numerous studies documenting the monomer release from acrylic orthodontic appliances in the oral cavity (9, 10). (ac.ir)
has reported that the greatest monomer release is during the first day after acrylic preparation (12). (ac.ir)

In the clotting cascade, the various blood coagulation factors function in concert to produce a balance between fibrin clot formation and its subsequent degradation. (medscape.com)

The degree of conversion, maximum rate of polymerization and water sorption/solubility of unfilled resins and the flexural strength and microhardness of composites (after 24 h storage in water and 3 months storage in a 75 vol% ethanol aqueous solution) were evaluated. (elsevierpure.com)

Then obtained by chemical polymerization. (samtop.com)

PTFE micro-powder products based on controlled degradation process may be made with virgin or recycled based PTFE. (com.vn)

In this regard, it is expected that materials' degradation and monomer release be accelerated in the oral cavity. (ac.ir)

Previously we structurally characterized five glucosylated lactose derivatives (F1-F5) with a degree of polymerization (DP) of 3-4 (GL34), products of Lactobacillus reuteri glucansucrases, with lactose and sucrose as substrates. (springer.com)
The degradation products were identified by mass spectroscopy, gas chromatography-mass spectroscopy and fourier transform infra-red spectroscopy. (gla.ac.uk)
one of the degraded products was the monomer itself, bis(1,3-diketone) (indicating recyclability of the monomer), and the other one was a dihydroxy compound derived from the bis (diazocarbonyl) compound and THF used as other monomers. (eurekalert.org)

Different degrees of degradation seem to work better in some specific applications. (com.vn)
Combinations of raw material type and varying degrees of degradation result in different pathways to achieve the desired RC product with specific performance similar with the original non-RC version. (com.vn)

The central feature of this protein was a posttranslational conversion of the host-encoded cellular prion protein (PrPC) to an abnormal isoform, termed PrPSc, that consists of ''small proteinaceous infectious particles that resist inactivation by procedures which modify nucleic acids," ie, radiation, heat, or enzymatic degradation. (medscape.com)

Depending on the fibrinogen abnormality, defects may occur in one or more of the steps in fibrin clot formation, although the most common defect involves polymerization of the fibrin monomer. (medscape.com)

Their particles can contain 10,00 to 200,00 monomers. (prlog.org)
Magnetite loaded cross-linked polystyrene composite particles prepared by modified suspension polymerization and their potential use as adsorbent for arsenic(III). (mpg.de)
Features of emulsion polymerization - how does the monomer move from the droplets into the latex particles? (mpg.de)

Recovered monomers can be re-manufactured into the same polymer formulation, without loss of performance, as well as other polymer formulations with differentiated properties. (nature.com)

The controlled degradation of a selected polycarbonate is also examined using TBD as catalyst leading to a new type of bicyclic oxetane. (iciq.org)

Researchers are constantly coming up with anti-foulant formulations that can prevent polymerization at its initial phase. (turbomachinerymag.com)

The nanocomposite structure at the variation of the laser density and of the MMA monomer flow was studied. (hindawi.com)

Anatomy21

Organisms7

Chemicals and Drugs124

Analytical, Diagnostic and Therapeutic Techniques and Equipment37

Phenomena and Processes65

Disciplines and Occupations2

Technology, Industry, Agriculture18

Information Science3

Health Care3

Polymers16

Thermal13

Resistance to degradation in ethanol2

Resin monomers2

Mechanisms3

Hydrophilic5

Molecular8

Poly3

Stability1

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Lignin3

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Characteristics1

Oxidative1

Additives1

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BisGMA3

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RAFT1

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Acrylic3

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PTFE1

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