Polymer science glass transition temperature

Figure 10.7 DSC curves of polyethylene terephthalate)-poly(acrylonitrile-butaliene-styrene) (PET-ABS) blends (a) conventional DSC first and second heating curves with heating and cooling rate of lOKmin-1 and (b) temperature modulated DSC (TMDSC) first heating curves with /3=2Kmin 1, p = 60s and 5= 1K. Tg, glass transition temperature. (Reproduced with permission from T. Hatakeyama and F.X. Quinn, Thermal Analysis Fundamentals and Applications to Polymer Science, 2nd ed., John Wiley Sons Ltd, Chichester. 1999 John Wiley Sons Ltd.)...

Tomic, E.A.J. 1965. Glass transition temperatures of poly(methyl methacrylate) plasticized with low concentrations of monomer and diethyl phthalate. Applied Polymer Science 9, 3745-3818. 

Articles on special types of polymers in various volumes of the Encyclopedia of Polymer Science and Engineering, tabulations in the Polymer Handbook, and product brochures and catalogs on commercial polymers, were among the sources of experimental data used for the glass transition temperature. 

Figure 8.9. Approximate position of dielectric or mechanical loss at 1 Hz shown on a reduced temperature plot T/Tm where T is the melting point temperature for a linear polymer molecule. Tg is the glass transition temperature. Reprinted from ref. I2l with permission. Copyright 1985 Elsevier Science Ltd. Kidlington, Oxon, UK.

Kozlov, G. V. Beloshenko, V. A. Stroganov, I. V. Lipatov, Yu.S. The intercommunication between glass transition temperature change and cross-linked polymers structure at heat aging. Reports of National Academy of Sciences of Ukraine, 1995, 10, 117-118. 

In addition to the above, polymer dissolution rate data have been used to determine glass transition temperature and other thermodynamic parameters associated with polymorphic changes [21]. Dissolution has also found a variety of uses in the pharmaceutical sciences. In the development of microcapsules for sustained release dosage forms [22], the mechanism of drug transport is governed by the dissolution of the polymer. Cooney [23] studied the dissolution of pharmaceutical tablets in the design of sustained release forms. Ozturk et al. [24, 25] showed that the dissolution of the polyacid, which is used in enteric-coated tablets, was the controlling step in the release kinetics mechanism. 

Meanwhile, developments in polymer science established that most long-chain linear polymers above their glass-transition temperatures can also exhibit rubberlike behavior whereby a network of molecular entanglements can serve the function of chemical cross links for deformation histories with oscillation periods shorter than the relaxation times of entanglement drift. It is this form of behavior of glassy polymers resembling that of rubbers which is a subject of principal concern and is discussed in Section 6.7. 

Fedderly, J., Compton, E., and Hartmaim, B. Additive group contributions to density and glass transition temperature in polyurethanes. Polymer Engineering and Science, 38(12), 2072-2076 (1998). 

Alessi, P., et al.. Plasticization of polymers with supercritical carbon dioxide Experimental determination of glass-transition temperatures. Journal of Applied Polymer Science, 2003.88(9) p. 2189-2193. 

Edwards, R.R., et aL, Chromatographic investigation of the effect of dissolved carbon dioxide on the glass transition temperature of a polymer and the solubility of a third component (additive). Journal of Polymer Science Part B-Polymer Physics, 1998. 36(14) p. 2537-2549. 

Before reviewing in detail the fundamental aspects of elastomer blends, it would be appropriate to first review the basic principles of polymer science. Polymers fall into three basic classes plastics, fibers, and elastomers. Elastomers are generally unsaturated (though can be saturated as in the case of ethylene-propylene copolymers or polyisobutylene) and operate above their glass transition temperature (Tg). The International Institute of Synthetic Rubber Producers has prepared a list of abbreviations for all elastomers [3], For example, BR denotes polybutadiene, IRis synthetic polyisoprene, and NBR is acrylonitrile-butadiene rubber (Table 4.1). There are also several definitions that merit discussion. The glass transition temperature (Tg) defines the temperature at which an elastomer undergoes a transition from a rubbery to a glassy state at the molecular level. This transition is due to a cessation of molecular motion as temperature drops. An increase in the Tg, also known as the second-order transition temperature, leads to an increase in compound hysteretic properties, and in tires to an improvement in tire traction... 

Journal of Applied Polymer Science 86, No.ll, 9th Dec.2002, p.2788-801 MECHANICAL PROPERTIES OF FILMS PREPARED FROM MODEL HIGH-GLASS-TRANSrriON-TEMPERATURE/LOW-GLASS TRANSITION-TEMPERATURE LATEX BLENDS Jiansheng Tang Daniels E S Dimonie V ... 

Journal of Polymer Science Polymer Physics Edition 39, No.14, 15th July 2001, p.1659-64 EFFECT OF RESIDUAL WATER AND FREE VOLUME ON THE GLASS-TRANSITION TEMPERATURE AND HEAT CAPACITY IN POLYSTYRENE/POLYVINYL ACETATE-CO-BUTYL ACRYLATE STRUCTURED LATEX FILMS... 

IM Hodge. Physical aging in polymer glasses. Science 267 1945 1947, 1995. BC Hancock, SL Shamblin, G Zografi. Molecular mobility of amorphous pharmaceutical solids below their glass transition temperatures. Pharm Res 12 799-806, 1995. 

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