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Topic: Polymer degradation

	Polymer degradation - Wikipedia, the free encyclopedia
		Polymer degradation is a change in the properties - tensile strength, colour, shape, etc - of a polymer or polymer based product under the influence of one or more environmental factors such as heat, light or chemicals.
		However the degradation process can be useful from the view points of understanding the structure of a polymer or recycling/reusing the polymer waste to prevent or reduce environmental pollution.
		Polymers molecules are very large on the molecular scale which derive their unique and useful properties from their size.
	en.wikipedia.org /wiki/Polymer_degradation (289 words)

	[No title]
		Polymeric degradation and with the diffusion method, the therapeutic compound is contained within the polymer membrane or matrix.
		The polymer is designed to degrade and release the therapeutic compound at a specific location in the body.
		As the polymer degrades, the therapeutic compound is released and made available to the body.
	www.antiagingresearch.com /hgh/transmucosal.php (893 words)

	Polymer Degradation and Stability
		Deteriorative reactions occur during processing, when polymers are subjected to heat, oxygen and mechanical stress, and during the useful life of the materials when oxygen and sunlight are the most important degradative agencies.
		For example, photodegradable plastics are now available, the recycling of polymeric products will become increasingly important, degradation and combustion studies are involved in the definition of the fire hazards which are associated with polymeric materials and the microelectronics industry is vitally dependent upon polymer degradation in the manufacture of its circuitry.
		Polymer properties may also be improved by processes like curing and grafting, the chemistry of which can be closely related to that which causes physical deterioration in other circumstances.
	gort.ucsd.edu /newjour/p/msg02719.html (355 words)

	Polymer Degradation and Stability. (Site not responding. Last check: 2007-10-23)
		M.N. Ismail, M.S. Ibrahim, M.A. Abd El-Ghaffar, Polyaniline as an antioxidant and antirad in SBR vulcanizates, Polymer Degradation and Stability 62 (2) (1998) pp.
		M.M. Abdel-Aziz, S.E. Gwaily, A.S. Makarious, A. El-Sayed Abdo, Ethylene-propylene diene rubber/low density polyethylene/boron carbide composites as neutron shields, Polymer Degradation and Stability 50 (2) (1995) pp.
		S.A. Abdel-Hafiz, Synthesis and characterization of hypochlorite oxidized poly (methacrylic acid)-starch composites, Polymer Degradation and Stability 55 (1) (1997) pp.
	elsevier.com /cdweb/journals/01413910/viewer.htt?viewtype=authors&... (917 words)

	Polymer Degradation
		When coupled with the complexity of the reaction processes in polymers, establishment of predictive models or damage functions is a formidable challenge.
		Predicting degradation rates: The quantitative prediction of long term performance in natural conditions depends on the ability to predict the rate of degradation in natural weathering.
		The intrinsic dependence of the development of the degraded layer on exposure conditions means that it can be inherently difficult to establish rate equations which can be transferred meaningfully from artificial weathering tests to natural exposure.
	www.azom.com /details.asp?ArticleID=171 (1073 words)

	Using ¹⁷O NMR Spectroscopy to Investigate Polymer Degradation Research Brief (Site not responding. Last check: 2007-10-23)
		Understanding polymer aging and degradation is crucial for accurate prediction of polymer lifetime, durability and reliability.
		The elucidation of the chemical and physical mechanisms at the molecular level leading to polymer degradation is an important objective in achieving this goal.
		O NMR and isotopic enrichment, the difficulty of distinguishing the degradation species signal from the dominant unaged polymer signal can be eliminated, thus providing a powerful tool for the investigation of degradation in polymer systems.
	www.sandia.gov /materials/sciences/factsheets/SpecPolyDegrad.html (346 words)

	Energy Citations Database (ECD) - Energy and Energy-Related Bibliographic Citations
		Most research on polymer degradation is for single polymers, even though the thermal decomposition of polymer mixtures is of interest both practically and theoretically.
		Polymer degradation rates depend on the mixture type, and adding a polymer can increase, decrease, or leave unchanged the degradation rate of the first polymer.
		The results indicated that, because of the interaction of mixed radicals with polymer by hydrogen abstraction, the polystyrene degradation rate decreases with increasing PAMS concentration.
	www.osti.gov /energycitations/product.biblio.jsp?osti_id=329251 (291 words)

	Research Interests: POLYMER CATALYTIC CRACKING (Site not responding. Last check: 2007-10-23)
		Polymer binders are expected to decompose completely below temperatures required for ceramic sintering.
		Polymers that we have studied extensively under ceramic sintering conditions are poly(vinyl butyral), poly(butyl methacrylate), and a multifunctional acrylic polymer.
		We are also investigating the effect of ionic salts on the thermal degradation processes of poly(methyl methacrylate) and poly(2-hydroxyethyl methacrylate) as well as the effect of various metals and metal oxides on the thermal degradation processes of polyaminoquinones that have been proposed as new corrosion inhibiting coatings.
	faculty-staff.ou.edu /W/Robert.L.White-1/h_res4.htm (281 words)

	1999 Fire Publications - Transient Modeling of Thermal Degradation in Non-Charring Solids. (Site not responding. Last check: 2007-10-23)
		After a preliminary study, three different solid degradation models were chosen from the literature, and their corresponding mass and energy conservation equations and boundary conditions were assembled.
		Various other parameters such as the polymer refractive index, polymer absorption coefficient, convective heat loss, solid fuel thickness and external radiative heat flux were changed to discuss their effects on the quantitative as well as qualitative change in the mass loss rate.
		Finally, depending on the solid degradation model used, the addition of gray radiation to the energy equation was shown to augment or diminish the mass loss rate.
	fire.nist.gov /bfrlpubs/fire99/art157.html (391 words)

	Degradation of Polymers
		Degradation is clearly apparent from this 1930’s shoehorn made of celluloid.
		The degradation of plastics can be said to begin as soon as the polymer is synthesised, and is increased by residual stresses left by moulding processes.
		If degrading cellulose esters are not isolated, the acidic fumes will infect similar objects stored close by and initiate degradation there.
	www.azom.com /details.asp?ArticleID=1655 (996 words)

	Article - Additives to make conventional polymers degradable
		For non-degradable polymers that contain a high percentage of biodegradable additives, the additives are degraded but the skeleton of the non-degradable polymer continues to pollute the environment.
		Biodegradation, for non-biodegradable polymers, is obtained by using high levels of biodegradable additives.
		Table 3 displays the molecular weight decrease by thermo-oxidative degradation of PE containing pro-oxidant (manganese stearate) during 1 week at temperatures from 50°C to 70°C. The lifetime to decrease the molecular weight to 10,000 at 25°C is roughly 2.5 to 4.5 years.
	www.specialchem4polymers.com /resources/articles/article.aspx?id=1465 (1137 words)

	Physiological and Chemical Investigations into Microbial Degradation of Synthetic Poly(cis-1,4-isoprene) -- Bode et al. ...
		It is assumed that enzymatic degradation of poly(cis-1,4-isoprene)
		The polymers were dissolved in toluene at a concentration of 2 g/liter overnight and passed through a 0.45-µm-pore-size filter
		The biochemical reactions which cleave the polymer and the subsequent reactions leading to central metabolism are unknown.
	aem.asm.org /cgi/content/full/66/9/3680 (3151 words)

	OSEL - Research Program Areas - Materials Characterization and Polymer Degradation
		The degradation route and mechanisms are also evaluated throughout the total product life cycle in order to predict materials/medical device performance and to ensure reliability and quality.
		The materials degradation program evaluates the chemical, thermal, and environmental degradation of materials and the affect of degradation on medical device performance and safety.
		In addition to identifying the degree and mechanism of materials degradation, several models of materials degradation both in vivo and in vitro have been developed to predict the effect of the human body on materials in terms of degradation routes and ultimate outcome of degradation products.
	www.fda.gov /cdrh/osel/programareas/materialscharacter.html (1939 words)

	Chemical Physics of Polymer Degradation and Stabilization (Site not responding. Last check: 2007-10-23)
		The chemical physics of polymer degradation and stabilization concerns itself not only with the behaviour of polymeric materials and the preservation and regulation of their properties but also with the development of new materials based on the chemical and physical modification of polymers through degradation.
		Thermal, thermo-oxidative, mechanical and photodegradation, degradation as a result of electrical fields and discharges and combustion processes are discussed extensively.
		Special attention is given to stabilization of solid polymers and the prediction of long-term stability of polymer materials.
	www.vsppub.com /books/chemi/bk-ChePhyPolDegSta.html (183 words)

	Stabilisers for Polyolefins (Rapra Review Report 132)
		The polymer industry faces a never-ending challenge to improve the stability and lifetime of polymer products.
		Demanding requirements can only be reached by employing small amounts of appropriate stabilizers, which serve to maintain or even improve the initial properties of polymeric materials.
		It also elucidates some of the physical and chemical aspects of such products when incorporated in the polymer matrix, discussing stability during weathering, heat aging, and processing.
	www.polysurfacesbookstore.com /pages/3549.html (197 words)

	AgeAlert - Polymer Aging Concepts, Inc. - RFID Tag Monitoring System
		Because the AgeAlert™ technology appears to work with virtually any polymeric material, potential applications for AgeAlert™ include degradation monitoring for most any product made of rubber, plastic or composite materials; however, further research will be necessary to adapt the technology for many of these applications.
		Research conducted at Polymer Aging Concepts, Inc. and Georgia Tech indicates that patent-pending AgeAlert™ technology should be able to measure the condition of virtually any degradable product.
		Currently, Polymer Aging Concepts, Inc. is collecting market research on the many areas where AgeAlert™ could be used to determine the best fit for the next major research effort; we seek strategic partners for this next research endeavor.
	www.polymeragingconcepts.com (300 words)

	airconditioner.ca - Polymer Properties (Site not responding. Last check: 2007-10-23)
		Dow Specialty Monomers' DVB is a versatile cross-linking agent used to improve polymer's chemical & physical properties with only small amounts required to receive such benefits.
		Micromuscle's electro-active polymers (EAP) can be used in a wide number of medical devices.
		Photoconducting polymers doped with nonlinear optical chromophores have emerged as efficient and inexpensive photorefractive (PR) materials.
	www.airconditioner.ca /Polymer-Properties/reference/search (244 words)

	43. : Modeling of Polymer Degradation in SLS
		Abstract A simple computer model has been developed to predict the thermal degradation of polymer binders used in the fabrication of composite green shapes from high temperature ceramic materials.
		Decomposition rate kinetics of the polymer materials were determined and incorporated into the model.
		The polymer degradation occurring in three separate powder systems was determined as a function of applied laser energy.
	home.att.net /~edgrenda2/sf94/sf94_43.htm (157 words)

	Center for Biodegradable Polymer Research
		Develop biodegradable polymers that when disposed in biologically active environments are completely converted to biological products (biogas, humic matter, biomass, etc.) within a suitable period.
		The biodegradable polymers as well as degradation products must be environmentally compatible causing no deleterious effects on the environment.
		Provide leadership in stimulating biodegradable polymer science and technology within the international community through publications, presentations at meetings, founding and editing the Journal of Environmental Polymer Degradation, organization and planning scientific meetings on biodegradable materials and active participation in the Bio/Environmentally Degradable Polymer Society and the ASTM subcommittee on environmentally degradable polymers.
	bprc.caeds.eng.uml.edu (330 words)

	Books by Keyword: Polymer Degradation
		Thermal Degradation of Polymeric Materials, Krzysztof Pielichowski and James Njuguna, 1 859 57498 x, Rapra, 2005, This book summarizes recent developments in the study of the thermal degradation of polymers.
		Sterilisation of Polymer Healthcare Products, Wayne Rogers, 1 859 57490 4, Rapra, 2005, This book offers a thorough description of the conventional sterilization methods — ethylene oxide, gamma and electron-beam...
		The Effect of UV Light and Weather on Plastics and Elastomers, Plastics Design Library Staff, 1 884 20711 1, Plastics Design Library, 1994, Ultraviolet rays, heat and moisture cause millions of dollars of damage every year to materials exposed to the environment.
	polysurfacesbookstore.com /keyword_books.html?id=Polymer+Degradation (412 words)

	Handbook of Polymer Degradation, 2nd Edition (#0131) (Site not responding. Last check: 2007-10-23)
		Focusing on the basics of photo- and biodegradability, as well as environmental issues engendered by increased use of polymers in many industries, this book exhaustively examines the lifecycle of polymers from the most current theoretical and practical perspectives.
		Containing over 2,500 references, tables, structures, equations, and drawings, the Handbook of Polymer Degradation, Second Edition provides a wealth of up-to-date information for environmental, health, and materials scientists; polymer, plastics, and chemical engineers; and upper-level undergraduate and graduate students in these disciplines.
		Additives and Stabilizers in Polymers; Mechanism of Polymer Degradation and Stabilization; Controlled Degradation and Stabilization; Wavelength Sensitivity of Polymers.
	www.4spe.org /training/products/0131.php (149 words)

	(WO 01/92389) METHOD OF REDUCING DEGRADATION IN POLYMERS (Site not responding. Last check: 2007-10-23)
		(57) A method for reducing degradation during processing of polymers.
		An effective amount of a foam cell nucleating agent to reduce degradation in a polymer is added to the polymer.
		The polymer and the foam cell nucleating agent are mixed to obtain a molten plastic and processed to obtain an unfoamed product, resulting in a reduction of degradation in the unfoamed product.
	wipo.int /cgi-pct/guest/getbykey5?KEY=01/92389.011206&ELEMENT_SET=DECL (189 words)

	Applied Science 411/511 (Site not responding. Last check: 2007-10-23)
		This course will be concerned with the environmental degradation of common synthetic polymers and how it can be prevented.
		A principal objective of the course is to provide students with the information they need in order to predict the effects of environmental stress on polymer structures and properties.
		Another objective is to enable students to choose effective methods for enhancing polymer lifetimes.
	chemistry.wm.edu /courses/chem656 (162 words)

	(WO 99/41437) PROCESS FOR PREPARING POLYKETONE FIBRES (Site not responding. Last check: 2007-10-23)
		(57) The invention pertains to a process for preparing thermoplastic fibres by melt-spinning an alternating co-polymer composed of alkenes and carbon monoxide in which the polymer is heated to a temperature of at least T
		being the temperature at which the molten polymer is free of crystallisation nuclei, and where the residence time of the polymer at a single temperature or different temperatures above the polymer melting point satisfies (I), wherein t
		) and A and B are determined by measuring the viscosity of the polymer at different temperatures and residence times.
	wipo.int /cgi-pct/guest/getbykey5?KEY=99/41437.990819&ELEMENT_SET=DECL (195 words)

	Rapra Bookstore (Site not responding. Last check: 2007-10-23)
		Advanced Polymer Composites and Polymers in the Civil Infrastructure
		Impact and Dynamic Fracture of Polymers and Composite
		Polymer Science and Industrial Research in the Fast-changing Age
	www.rapra.net /bookstore/atozlist.asp (2132 words)

	Chemical Physics of Polymer Degradation and Stabilization: Contents (Site not responding. Last check: 2007-10-23)
		Physical mechanisms of the impact of molecular physics on the kinetics and reactivity of polymers
		Kinetics and mechanism of initiated oxidation of polymers
		Structure and supermolecular organization of polymers subjected to mechanical stress
	www.vsppub.com /books/chemi/cbk-ChePhyPolDegSta.html (147 words)

	Forest Products Laboratory -- Forest Service -- USDA (Site not responding. Last check: 2007-10-23)
		Leachability of Boron from Wood Treated with Natural and Semi-Synthetic Polymers and Calcium Precipitating Agent (PDF 47 KB) Kartal, S.N.; Green, F. Holz.
		Then statistically insignificant vertical and horizontal migration of these PAH suggests that they either evaporated or were degraded in the ballast.
		Surface Chemistry Changes of Weathered HDPE/Wood-Flour Composites Studied by XPS and FTIR Spectroscopy (PDF 221 KB) Stark, Nicole M.; Matuana, Laurent M. Polymer Degradation and Stability.
	www.fpl.fs.fed.us /document-lists/div_new.html (6069 words)

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