Back , Main menu , PSLC In 1839 Charles Goodyear invented a process called vulcanization, which made rubber more durable and more useful at hot and cold temperatures. Vulcanization crosslinks rubber. That is, it ties all the chainlike rubber molecules together to form one big molecule. This does a lot for the rubber, but it can also make rubber difficult to process. Think about it. A material made of one molecule cant really flow into a mold, and it cant be shaped or worked very easily. A material made of crosslinked rubber has to be shaped before it is crosslinked. Crosslinking also makes rubber difficult to recycle. Some kinds of synthetic rubber arent crosslinked, however. They can be molded and remolded again and again. They are called thermoplastic elastomers. Thermo- means "heat", and plastic means "moldable". Elastomer is just a fancy word that means "rubber." So a thermoplastic elastomer is a rubber that can be molded when it is heated. While it is wonderful that thermoplastic ...
China Sbs Pellets /Thermoplastic Elastomer/ Raw Material for Asphalt Modification, Find details about China Styrene Butadiene Styrene Rubber, Sbs for Bitumen Modification from Sbs Pellets /Thermoplastic Elastomer/ Raw Material for Asphalt Modification - Qingdao Shengdetong Industrial Co., Ltd.
en] We investigate the microscopic morphology of thin films of symmetric triblock copolymers synthesized via a two-step "living" radical polymerization of n-butylacrylate and methyl methacrylate. These copolymers with low poly(methyl methacrylate) contents constitute a new class of potential thermoplastic elastomers with higher service temperature and oxidation resistance compared to conventional polydiene−polystyrene-based thermoplastic elastomers. The straightforward synthetic pathway allows for strict control of molecular weight, molecular-weight distribution, and composition. The presence in the copolymer of immiscible segments covalently bound to each other leads to phase separation on the nanometer scale. Regular organization of the phase-separated nanodomains is observed in real space by scanning force microscopy. The data point to a strong contrast in the local mechanical properties, corresponding to the microphase morphology. Cylinders of the minority phase are found to orient ...
China Thermoplastic Elastomer Sis Styrene Isoprene Styrene Pellets, Find details about China Sis Rubber, Styrene Isoprene Styrene Rubber from Thermoplastic Elastomer Sis Styrene Isoprene Styrene Pellets - Qingdao Shengdetong Industrial Co., Ltd.
Pneumatic rubber tire with a tread composed of a rubber blend of a base of at least two synthetic elastomers composed of (i) specialized isoprene/butadiene copolymer elastomer having a low Tg in a range of about -70 to about -100 C. and (ii) a diene based elastomer having a Tg in a range of about -5 to about -30 C. together with a minor amount of natural cis 1,4-polyisoprene rubber. Selection of the base of the said two synthetic elastomers having spaced apart, or spatially defined, Tgs of at least 40 C. is an important feature of the tread rubber blend. Representative examples of contemplated elastomers with Tgs in a range of about -5 to about -30 C. are 3,4-polyisoprene elastomer, styrene/isoprene copolymer elastomer and high vinyl polybutadiene elastomers. In one aspect, the tread rubber blend is reinforced with reinforcing filler composed of carbon black or a combination of carbon black and silica accompanied by a coupling agent.
This invention relates to a composition comprising a polybutadiene rubber containing a polymer obtained by block or graft polymerization of cis-1,4-polybutadiene with syndiotactic (syn)-1,2-polybutadiene, alone or blended with the other diene rubber, said syn-1,2-polybutadiene being crystallized and in a short fiber-like shape, and a breaking resistance characteristic and reinforcement characteristic being considerably improved by specifying the diameter and length of said short fiber, which is suitable for various parts of tire or industrial materials, and further relates to a composition of said polybutadiene rubber to which a carbon black is added for preferably used as a chafer or tread of tire, and still further relates to said composition to which a carbon black and an antioxidant are added for preferably used as a rubber blend composition for side wall.
Thermoplastic elastomer compositions of the present invention comprise a blend of from about 10 to about 50 parts by weight of a crystalline 1-olefin polymer, from about 80 to about 15 parts by weight of a styrene-butadiene rubber, and from about 5 to about 50 parts by weight of bitumen. The thermoplastic blends have unexpectant increases in properties, especially tear strength, tensile strength, high temperature (100 C.) tear strength, and smooth surfaces when injection molded. Moreover, the bitumen lowers the injection molding pressure, thus enabling larger parts to be molded. The compositions, which may be partially cured, also have excellent aging properties. The compositions are a true thermoplastic in that they can be repeatedly processed and yet maintain their good physical properties.
RTP Company can support your medical device development needs from virtually every angle. Not only do we provide standard products that are pre-tested to ISO 10993 biocompatibility standards, but we also offer custom and highly functionalized TPEs that are formulated to dissipate static electricity, provide radiopacity, and/or lower sliding friction force.. At RTP Company, we have structured our TPE product line to give the medical device design engineer ultimate flexibility. Our line of standard products provides time-tested performance in an array of devices, while our experienced R&D group is able to custom formulate unique TPE alloys and incorporate functional additives in support of your most demanding product developments.. For more information, view our innovation bulletin on Thermoplastic Elastomers for Medical Devices…. View Innovation Bulletin View alternative languages of this brochure: ...
Chemical Resistance, Volume 2: Thermoplastic Elastomers Thermosets and Rubbers, 9781282013483, available at Book Depository with free delivery worldwide.
One comprehensive volume holding an applicable knowledge of the chemistry, processing, and all properties, and uses of thermoplastic elastomers.
Segmented thermoplastic copolyester elastomers containing recurring polymeric long chain ester units derived from phthalic acids and long chain glycols and short chain ester units derived from phthalic acids and 1,4-butanediol or 1,4-butenediol. The elastomers also contain between about 0.1% and about 5% by weight of said copolyester of 3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid triester with 1,3,5-tris-(2-hydroxyethyl)-s-triazine-2,4-6-(1H, 3H, 5H) trione.
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Polyurethanes combine the elastic properties of elastomers with the processability of thermoplastic materials. Seals made of polyurethanes provide excellent wear and pressure resistance and avoid leakage. Due to their elasticity and flexibility, they are easy to install. Special sealing polyurethane grades have a superior compression set and relaxation performance as well as temperature stability compared to commodity industrial grades ...
0046]The above thermoplastic elastomer composition is obtained by previously fusing and kneading the thermoplastic resin and the elastomer (uncured one in the case of rubber) by use of a biaxial kneader/extruder or the like, and thereby dispersing the elastomer component in the thermoplastic resin forming a continuous phase. When the elastomer component is cured, elastomer may be dynamically cured by adding a vulcanizing agent during the kneading. Additionally, although various compounding agents (other than a vulcanizing agent) may be added to the thermoplastic resin or elastomer component during the above kneading, it is preferable that these agents be previously mixed therein before the kneading. There is no particular limitation as to a kneader used for the kneading of the thermoplastic resin and the elastomer, and there can be listed a screw extruder, a kneader, a banbury mixer, and a biaxial kneader/extruder as examples of the kneader. For the purpose of kneading of the resin component and ...
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Kuraray Co., Ltd has introduced its range of Septon V thermoplastic elastomers, which it describes as "hydrogenated styrene thermoplastic elastomers". Although the company does not specifically mention the abbreviation SEBS, Kraton has been selling hydrogenated styrenic elastomers using the SEBS acronym for many years. Kuraray said, "Unlike earlier Septon products, the Septon V Series contains a crosslinkable hard block and makes it reactive. Kuraray has also developed special compounding technology which makes it possible to cross-link the hard block as well as the soft block…. ...
Thermoplastic Polyester Elastomer (TPEE) Market Thermoplastic Polyester Elastomer (TPEE) is a block copolymer who contains a hard segment of polyester and a soft segment of polyether; wherein the amorphous is formed from the soft segment of polyether and the uncrystallized polyester. Micro-crystals play a role as physical crosslinking points formed from the hard segment of…
1,3-Butadiene is used as an intermediate in the production of elastomers, polymers, and other chemicals. Of the 1,3-butadiene used in 1978, 44% was used to manufacture styrene-butadiene rubber (a substitute for natural rubber, produced by copolymerization of 1,3-butadiene with styrene), and 19% was used to produce polybutane elastomer (a substance that increases resistance of tire products to wear, heat degradation, and blowouts). Chloroprene monomer, derived from 1,3-butadiene, is used exclusively to manufacture neoprene elastomers for non-tire and latex applications. Commercial nitrile rubber, used largely in rubber hoses, seals, and gaskets for automobiles, is a copolymer of 1,3-butadiene and acrylonitrile. Acrylonitrile- butadiene- styrene resins, usually containing 20%-30% 1,3-butadiene by weight, are used to make parts for automobiles and appliances. Other polymer uses include specialty polybutadiene polymers, thermoplastic elastomers, nitrile barrier resins, and K resins®. 1,3-Butadiene ...
Global Polybutadiene Market to Reach $9. 5 Billion by 2027. Amid the COVID-19 crisis, the global market for Polybutadiene estimated at US$7. 3 Billion in the year 2020, is projected to reach a revised size of US$9.New York, July 31, 2020 (GLOBE NEWSWIRE) -- Reportlinker.com announces the release of the
TABLE-US-00001 TABLE 1 Examples Comparative Examples 1 2 3 4 1 2 3 4 (A) Block Wt % 36.1 37.4 34.8 35.4 -- 45 30 30 terpolymer (A) Polyolefin- -- -- -- -- 100 -- -- -- based rubber (B) Paraffin oil 39.7 37.4 41.8 39.0 -- 30 30 25 (C) Polyolefin- 2.6 2.8 2.6 2.6 -- 10 20 10 based resin (D) Inorganic 10.8 11.2 10.4 12.4 -- 10 8 25 additive (E) Polyphenylene 10.8 11.2 10.4 10.6 -- 5 12 10 ether-based resin (F) Silicon-based Parts 0.35 0.4 0.35 0.35 -- -- -- -- resin by weight Surface hardness (shore A) 35 40 32 37 45 48 67 52 23° C. Tensile strength 66 65 59 63 85.0 40 115 35 (kgf/cm2) Elongation rate 834 821 848 841 890 750 800 450 (%) Permanent 1.5 2.1 1.4 2.1 1.3 4.0 7.0 6.0 elongation and extension rate 100° C. Tensile strength 14 12 10 14 15 14 35 8 (kgf/cm2) Elongation rate 452 333 343 456 380 430 500 350 (%) Permanent 8.6 7.2 7.3 9.2 6.9 12 15 20 elongation and extension rate ...
Summary of Facts and Submissions. I. Mention of the grant of European patent No. 0 698 054 in respect of European patent application No. 94 916 028.7, filed on 5 May 1994 as International application No. PCT/US94/05002 in the name of Supreme Corq, was announced on 17 April 2002 (Bulletin 2002/16).. II. The patent, entitled Molded Closure for a Liquid Container was granted with fifteen claims, Claim 1 reading as follows:. 1. A molded stopper for removable insertion into a wine bottle obtainable from a composition comprising a thermoplastic elastomer and a blowing agent, wherein the thermoplastic elastomer is at least one styrene block copolymer selected from a styrene-ethylene-butylene-styrene block copolymer (SEBS), a styrene-isoprene-styrene block copolymer (SIS), and a styrene-ethylene/propylene-styrene block copolymer (SEPS).. Claims 2 to 14 were, either directly or indirectly, dependent on Claim 1. Claim 15 was directed to a method of making the moulded stopper according to Claim 1 ...
United States Patent @iiiice 3,018,302 Patented Jan. 23, 1962 NOVEL CYCLIC PHOSPHORIC ACID ESTER AMIDES, AND THE PRODUCTION THEREOF Herbert Arnold, Bielefeld, Norbert Brock, Wadersloh, and Friedrich Bourseaux, Bielefeld, Germany, assignors to Asta-Werke Aktiengesellschaft Chemische Fabrik, Brackwede, Germany No Drawing. Filed Apr. 15, 1958, Ser. No. 728,568 Claims priority, application Germany Feb. 10, 1956 9 Claims. (Cl. 260-461) This invention relates to novel cyclic phosphoric acid ester amides, and the production thereof. This application is a continuation-in-part of our copending patent application Serial No. 638,235, filed February 5, l957, entitled Novel cyclic phosphoric acid ester amides and the production thereof. For a number of years, compounds of the type of the so-called nitrogen mustard gas which conform to the following formula in which X is a halogen atom, preferably a chlorine atom, have found considerable medical interest for the treatment of malignant growths and similar ...
US. Cl. 260-75NH Claims ABSTRACT OF THE DISCLOSURE Polyurethane elastomers having improved hydrolytic stability are prepared from 4,4-methylene bis(cyclohexylisocyanate), neopentyl adipate polyester and an aromatic diamine. POLYURETHANE-UREA ELASTOMERIC COMPOSITIONS This invention relates to polyurethane elastomers, having improved hydrolytic stability, which are prepared from 4,4-methylene bis(cyclohexylisocyanate); neopenyl adipate polyester; and an aromatic diamine. It is known that polyurethane compositions can be prepared by chain-extending isocyanate-terminated prepolymers with a curing agent containing active hydrogen groups, such as a diamine, polyol, water and the like. The prepolymers are commonly prepared by condensation of a polyester or polyether with an excess of an aromatic diisocyanate. Where high performance elastomers are desired the preferred curing agents are aromatic diamines. However, the use of aromatic diamines presents a processing problem with many prepolymers. For ...
The invention relates to an electrically conductive elastomer mixture and to a method. The mixture comprises a thermoplastic styrene elastomer and, as an electrically conductive filler, metal-containing particles. The mixture further comprises a polymer which is an acid-grafted, acid-anhydride-grafted or acid-copolymer and which forms an IPN (Interpenetrating Polymer Network) network structure with the styrene elastomer.
This invention concerns a method for the preparation of polyurea elastomers, comprising: (a) reacting an amine chain extender with dialkyl maleate to form an aspartic ester, wherein the chain extender has a molar amount of amine groups that is greater than the moles of dialkyl maleate; (b) blending the aspartic ester with one or more polyoxyalkyleneamines to prepare a resin blend; (c) contacting the resin blend with an isocyanate under conditions effective to form a polyurea elastomer. This invention concerns a method for the preparation of polyurethane elastomers, comprising: (a) reacting an diamine chain extender with dialkyl maleate or fumarate, wherein the mole ratio of primary amine functionality in the diamine chain extender to dialkyl maleate or fumarate is more than 1:1; (b) coating a substrate with effective film forming amounts of the product of step (a), an isocyanate, and a polyhydroxyl compound under conditions effective to form a the
The present invention is directed generally to the use of propylene-based elastomers in articles. The propylene-based elastomers have isotactic polypropylene crystallinity, a melting point by DSC of 110 C. or less, a heat of fusion of from 5 to 50 J/g, and comprise at least 75 wt % propylene-derived units, at least 6 wt % ethylene-derived units, and optionally diene-derived units. The present invention is also directed to processes for making articles comprising propylene-based elastomers.
For all practical purposes, the useful life of a plastic component is equal to its fatigue life under conditions of cyclic loading such as those that occur in vibration. Equally important to materials engineers and designers are abrasion, friction and wear-tribological properties. Over 80 generic families are covered including thermoplastics, thermosets, thermoplastic elastomers and rubbers. Neat resins, blends and alloys, plastics with various combinations of fillers, additives and more are covered. Also covers plastics mated to plastics and metals ...
In this work we present a new fabrication technique to print thin dielectric elastomer actuators (DEAs), reducing the driving voltage below 300 V while keeping good actuation performance. With operation voltages in the kV-range, standard DEAs are limited in terms of potential applications. Using thinner membranes is one of the few existing methods to achieve lower operation voltages. Typical DEAs have membranes in the 20-100 um range, values below which membrane fabrication becomes challenging and the membrane quality and uniformity degrade. Using pad printing we produced thin silicone elastomer membranes, on which we pad-printed compliant electrodes. We then fabricated DEAs by assembling two membranes back to back. We obtain an actuation strain of 7.5% at only 245 V on a 3 um thick DEA. In order to investigate the stiffening impact of the electrodes we developed a simple DEA model that includes their mechanical properties. We also developed a strain-mapping algorithm based on optical ...
An elastomer is a polymer with viscoelasticity (having both viscosity and elasticity) and very weak inter-molecular forces, generally having low Youngs modulus and high failure strain compared with other materials.[1] The term, which is derived from elastic polymer,[2] is often used interchangeably with the term rubber, although the latter is preferred when referring to vulcanisates.[3] Each of the monomers which link to form the polymer is usually made of carbon, hydrogen, oxygen or silicon. Elastomers are amorphous polymers existing above their glass transition temperature, so that considerable segmental motion is possible. At ambient temperatures, rubbers are thus relatively soft (E ≈ 3 MPa) and deformable. Their primary uses are for seals, adhesives and molded flexible parts. Application areas for different types of rubber are manifold and cover segments as diverse as tires, shoe soles, and damping and insulating elements. The importance of rubbers can be judged from the fact that global ...
Booktopia has Advances in Elastomers and Rubber Elasticity by Joginder Lal. Buy a discounted Hardcover of Advances in Elastomers and Rubber Elasticity online from Australias leading online bookstore.
Mitsui Chemicals, Inc. announced the launching of a new product, a syndiotactic elastomer NOTIO SN. The company manufactures and widely distributes elastomers (flexible polymeric materials) for uses which include automotive, packaging, and construction materials.
[113 Pages Report] Check for Discount on Global and Regional Spray Polyurea Elastomer (SPUA) Market Research Report 2017 report by HeyReport. Summary A Spray Polyurea Elastomer (SPUA) is derived from a...
Wacker Silicones has developed a new generation of thermoplastic silicone elastomers that combine the typical properties of silicones with advantages of a thermoplastic elastomer. A transparent polydimethylsiloxane/urea copolymer, Geniomer is cured through a physical process instead of a catalyst…
Metaltest provides durometer hardness testing in the two most common scales; ASTM D2240 type A and type D scales.. Durometer, like many other hardness tests, measures the depth of an indentation in the material created by a given force on a standardized presser foot. ASTM D2240 durometer allows for a measurement of the initial hardness, or the indentation hardness after a given period of time. The basic test requires applying the force in a consistent manner, without shock, and measuring the hardness (depth of the indentation).. The A scale is for softer vulcanized rubber, natural rubber, nitriles, thermoplastics, elastomers, flexible polyacrylics and thermosets, wax, felt and leather.. The D scale is for Hard Rubber, thermoplastic elastomers, hard plastics, and rigid thermoplastics.. ...
I have a second TPE that I developed during my time at Rethink Technologies, a classical dynamic vulcanizate thermoplastic elastomer, or "thermoplastic vulcanizate" (TPV). I originally proposed the development of an ETFE fluoroplastic matrix TPV, with FKM as the curing elastomer phase to Daikins Dai-Act program in 2001; they chose not to back it. But three years later, I was asked to consult on the project, started long before (but not, I think, before 2001): Daikins ETFE/FKM dynamic vulcanizate! I was flabbergasted, but I made a deal to work on the project. There were two teams, one in Osaka, the other in the Rethink lab, in New York. We got dramatically better results than the Osaka team, but I fell out of favor when I refused to let them file a patent without my name on it. I did file the patent as assigned to Daikin (no problem), but they had a problem with an American inventor. Daikin abandoned the patent in mid-prosecution, but it was still published. I created an ETFE-matrix TPV (30% ...
Sabu Thomas, PhD, is a Professor of Polymer Science and Engineering at the School of Chemical Sciences and Director of the International and Inter University Centre for Nanoscience and Nanotechnology at Mahatma Gandhi University, Kottayam, Kerala, India. The research activities of Professor Thomas include surfaces and interfaces in multiphase polymer blend and composite systems; phase separation in polymer blends; compatibilization of immiscible polymer blends; thermoplastic elastomers; phase transitions in polymers; nanostructured polymer blends; macro-, micro- and nanocomposites; polymer rheology; recycling; reactive extrusion; processing-morphology-property relationships in multiphase polymer systems; double networking of elastomers; natural fibers and green composites; rubber vulcanization; interpenetrating polymer networks; diffusion and transport; and polymer scaffolds for tissue engineering. He has supervised 68 PhD theses, 40 MPhil theses, and 45 Masters thesis. He has three patents to ...
By Patrick Raleigh, ERJ On-line news editor. Tarragona, Spain-Dow Chemical Co. has started up a 57-kilotonne-per annum plant in Tarragona to produce its new Versify range of propylene-ethylene copolymer-based plastomers and elastomers. The unit is a retrofit of an existing polyolefins facility, said a company spokeswoman.. The unit is the first commercial plant for Versify, which was launched in February, said a 16 Sept Dow statement. The facility, it added, will supply a range of end users, possibly encompassing packaging producers, manufacturers of thermoplastic elastomers, and converters…. ...
M. Kolahdoozan, R. Mirsafaei, S. Mallakpour, Polym. Bull., 2012, 68, 1239-1254. Synthesis and properties of new highly soluble poly(amide-ester-imide)s containing poly(ethylene glycol) as a soft segment. M. Kolahdoozan, R. Mirsafaei, S. Mallakpour, Polym. Bull., 2012, 68, 1239-1254. Synthesis and properties of new highly soluble poly(amide-ester-imide)s containing
Provided herein is a copolymer that includes a soft block (A) that contains poly(ester amide) (PEA) and a hard block (B). The copolymer can be any of AB, ABA or BAB type block copolymers. By varying the relative amount of the PEA block and the hard block, one can obtain a copolymer with a Tg for mechanical integrity in drug-delivery stent applications. The copolymer can be used alone or optionally in combination with a biobeneficial material and/or a biocompatible polymer to form an implantable device or a coating on an implantable device. When the copolymer is used in combination with a biobeneficial material, the copolymer and the biobeneficial material can be co-deposited or applied in sequence during the coating process. A coating formed of the copolymer may also include a bioactive agent. The implantable device can be implanted in a patient to treat, prevent, or ameliorate a disorder such as atherosclerosis, thrombosis, restenosis, hemorrhage, vascular dissection or perforation, vascular aneurysm,
The global thermoplastic polyester elastomer (TPEE) market size was estimated at 845.2 million tons in 2016. Rising substitution of thermosets and other conventionally heavy materials such as metals and wood is expected to remain a key driving factor for the industry over the forecast period.
Polybutadiene is a synthetic rubber (Polymer). About 70% of the produced polybutadiene rubber (PBR) is used in tyre manufacturing. Almost the remaining is used as an additive to improve the mechanical strength of plastics such as polystyrene and acrylonitrile butadiene styrene (ABS). Polybutadiene (BR) is the second largest volume synthetic rubber produced, next to styrenebutadiene rubber (SBR). Please post your selling/buying lead for this product or simply see below posts:
Formerly known as Materials Engineering Research Laboratory (MERL) Limited, Element Hitchin has over 25 years of experience in delivering world-class materials expertise in polymers, elastomers, thermoplastics, composites and structural adhesive related testing services
TY - CONF. T1 - Polyolefins containing `reactive p-methylstyrene groups. T2 - Proceedings of the 1998 56th Annual Technical Conference, ANTEC. Part 1 (of 3). AU - Chung, Tze-chiang. PY - 1998/1/1. Y1 - 1998/1/1. N2 - A new class of polyolefin co- and terpolymers containing `reactive p-methylstyrene groups will be discussed, which includes high Tm approximately 160 °C thermoplastics to low Tg ,-50 °C elastomers. The chemistry involves copolymerization of α-olefins (i.e. ethylene, propylene, 1-octene, etc.) and p-methylstyrene (p-ms), using metallocene technology. In turn, the p-ms groups in polyolefin are very versatile and can be interconverted to desirable functional groups or produce graft copolymers, such as PE-g-PS, PE-g-PMMA, PP-g-PMMA and EP-g-PMMA. They are very effectively interfacial reagents and can dramatically increase the interaction between polyolefin and other materials, such as nylons, glass and metals.. AB - A new class of polyolefin co- and terpolymers containing ...
D92 Test Method for Flash and Fire Points by Cleveland Open Cup Tester. D93 Test Methods for Flash Point by Pensky-Martens Closed Cup Tester. D146/D146M Test Methods for Sampling and Testing Bitumen-Saturated Felts and Woven Fabrics for Roofing and Waterproofing. D228/D228M Test Methods for Sampling, Testing, and Analysis of Asphalt Roll Roofing, Cap Sheets, and Shingles Used in Roofing and Waterproofing. D412 Test Methods for Vulcanized Rubber and Thermoplastic ElastomersTension. D413 Test Methods for Rubber Property--Adhesion to Flexible Substrate. D430 Test Methods for Rubber Deterioration--Dynamic Fatigue. D471 Test Method for Rubber PropertyEffect of Liquids. D543 Practices for Evaluating the Resistance of Plastics to Chemical Reagents. D570 Test Method for Water Absorption of Plastics. D573 Test Method for RubberDeterioration in an Air Oven. D624 Test Method for Tear Strength of Conventional Vulcanized Rubber and Thermoplastic Elastomers. D638 Test Method for Tensile Properties of ...
Communications DOI: 10.1002/anie.200705204 Ultrahigh-field NMR Spectroscopy Application of Ultrahigh-Field 59Co Solid-State NMR Spectroscopy in the Investigation of the 1,2-Polybutadiene Catalyst [Co(C8H13)(C4H6)]** Patrick Crewdson, David L. Bryce,* Frank Rominger, and Peter Hofmann* Dedicated to Professor Wolfgang A. Herrmann on the occasion of his 60th birthday Syndiotactic 1,2-polybutadiene (sPBD) is an important industrial polymer with a wide variety of uses;[1] however, there is only a very limited number of catalysts currently capable of producing this polymer with a high degree of syndiotacticity.[2] Only one such catalyst has been structurally characterized, when in 1967 Natta et al. published a low-resolution crystal structure of the cobalt complex [Co(h3 :h2-C8H13)(h4-C4H6)] (1).[3] Since then, no spectroscopic data have been published on this or any other sPBD catalyst, a fact which frustrates discussions on the mechanism of the reaction, though the mechanism of syndiotactic ...
A rotary bristle tool having a backing with a plurality of bristles extending therefrom. The bristles have a cross section and preferential orientation to control deflection during rotation of the tool. One embodiment is well suited for refining the inside surface of two-way and three-way corners. The backing and bristles are preferably integrally molded. The rotary bristle tool is molded from a moldable polymer such a thermoset polymer, thermoplastic polymer, or thermoplastic elastomer. The rotary bristle tool can include an attachment member molded integrally with the backing. Also disclosed is a method of making a rotary bristle tool and a method of refining a workpiece surface with a rotary bristle tool.
The in vitro vascular tissue engineering paradigm seeks to produce biologically responsive vascular substitutes using cells, biodegradable scaffolds, and bioreactors to mature the tissue for the potential treatment of vascular occlusions and to create 3D tissue models for pre-clinical testing. In this work, a poly (ester amide) (PEA) derived from from L-phenylalanine, sebacoyl chloride and 1,4 butanediol was synthesized and electrospun to form both 3D fibrous mats and tubular constructs. Both the polymer solution concentration and mandrel rotation speed were optimized to fabricate bead-free fibres. Cytocompatibility and proliferation studies using mesenchymal progenitor 10T1/2 cells showed PEA fibres were not cytotoxic and were able to support proliferation for 14 days. 10T1/2 cells demonstrated increased attachment and spreading for up to 7 days on fibrous mats but perfusion bioreactor studies on tubular scaffolds did not demonstrate sufficient cell infiltration. 10T1/2 cell differentiation studies
A new class of non-chain extended segmented copolymers that contained both urea and oxamide hydrogen bonding groups in the hard segment were synthesized. PDMS poly(urea oxamide) (PDMS-UOx) copolymers displayed thermoplastic elastomer behavior with enhanced physical properties compared to PDMS polyurea (PDMS-U) controls. Synthesis of a difunctional oxamic hydrazide terminated PDMS oligomer through a two-step end capping procedure with diethyl oxalate and hydrazine proved highly efficient. Solution polymerization of the oxamic hydrazide PDMS oligomers with HMDI afforded the desired PDMS-UOx segmented copolymer, which yielded optically clear, tough elastomeric films. Dynamic mechanical analysis showed a large temperature insensitive rubbery plateau that extended up to 186 ÚC for PDMS-UOx copolymers and demonstrated increased rubbery plateau ranges of up to 120 ÚC when compared to the respective PDMS-U control. The increase in thermomechanical properties with the presence of oxamide groups in the ...