Thermal degradation polycarbonates

It has already been shown (e.g. Chapters 20 and 21) that the insertion of a p-phenylene into the main chain of a linear polymer increased the chain stiffness and raised the heat distortion temperature. In many instances it also improved the resistance to thermal degradation. One of the first polymers to exploit this concept commercially was poly(ethylene terephthalate) but it was developed more with the polycarbonates, polysulphone, poly(phenylene sulphides) and aromatic polyketones. 

McNeill and Basan [151] studied the thermal degradation of blends of PVC with bisphenol-A polycarbonate. The structure of bisphenol-A polycarbonate is given in Eq. (42). 

Illustrative performance properties for a "general purpose polycarbonate," and for the same resin modified with the additive formulations "700" (without PTFE) and "800" (with PTFE) are summarized in Table IV (adapted from reference 32). It is clear that the objective of minimal effect on performance properties has been attained for this system. It is evident that flame retardant effectiveness attained with minimal levels of additive can provide optimum solutions to the problem of decreasing flammability without sacrifice in performance properties. Work documented to date suggests that in depth studies of thermal degradation such as reported for aromatic sulfonates in polycarbonates (28) would be rewarding for other systems. 

R. Balart, L. Sanchez, J. L6pez, and A. Jimenez, Kinetic analysis of thermal degradation of recycled polycarbonate/acrylonitrile-butadi-ene-styrene mixtures from waste electric and electronic equipment,... 

C. McMeill and A. Ricon, Thermal degradation of polycarbonates reaction conditions and reaction mechanisms, Polym. Degrad. Stab., 39, 13-19 (1993). 

H. Sato, K. Kondo, S. Tsuge, H. Ohtani, and N. Sato, Mechanisms of thermal degradation of a polyester flame retarded with antimony oxide/brominated polycarbonate studied by temperature programmed analytical pyrolysis. Poly. Degr. Stab., 62, 41-48 (1998). 

A comprehensive study of the thermal degradation of epoxy resins has been reported by Lee [239]. Their stability was found to be lower than that of polycarbonate, polyphenylene sulphide and teflon (Fig. 64). 

RIV 02] Rivaton a., Mailhot B., Soulestin I, et al., Comparison of the photochemical and thermal degradation of bisphenol-A polycarbonate and tiimethylcyclohexane-poly-caihormte . Polymer Degradation and Stability, vol. 75, no. l,pp. 17-33,2002. 

Sato, H., Kondo, K., Tsuge, S., Ohtani, H., and Sato, N., Thermal Degradation of Flame-Retarded Polyester with Antimony Oxide/Brominated Polycarbonate Studied by Temperature Programmed Analytical Pyrolysis Techniques, Polym. 

Condensation polymers can be regarded as a sequence of monomer units containing fxmctional groups immobilized into the polymer structure. Their decomposition pathways will often be dominated by the polarity and by the reactivity of the fxmctional groups within their structure, and their thermal decomposition reactions will be ionic and selective, rather than radical and imselective. Such are the thermal degradation processes occurring in polyesters, polyamides, polycarbonates, polyurethanes, polyureas, and in several other cases. ... 

Davis, A. and Golden, J. H., Competition between chain scission and cross-linking processes in the thermal degradation of a polycarbonate. Nature, 206, 397, 1965. 

McNeill, I.C. and Leiper, H.A. (1985) Degradation studies of some polyesters and polycarbonates 2. Polylactide Degradation under isothermal conditions, thermal degradation mechanism and photolysis of the polymer. Polymer Degradation and Stability, 11,309-326. 

Polyoxymethylene (POM) and polycarbonate (PC) often start thermal degradation from the chain ends. If their plastic products contain too many short chains, the products are liable to turn yellow in color, losing their good quality. 

L. H. Lee, Mechanisms of Thermal Degradation of Phenolic Condensation Polymers. 1. Studies on the Thermal Stability of Polycarbonate, J. Polym. Sci., Part A 2 2859 (1964). 

Formation of a polymer alloy is a common way to improve the property of PLLA. Many kinds of polymers such as polyethylene [70], polypropylene (PP), polystyrene (PS) [71], poly (methyl methacrylate) [72], bisphnol-A type polycarbonate, poly(E-caprolactone), poly(3-hydroxybuty-rate), poly (butylene succinate) (PBS) [73], poly(butylene succinate/adipate) (PBSA), acrylonitrile-butadiene-styrene have been used for preparing PLLA alloys, and some of which have been commercialized. However, there has been no discussion of the thermal degradation behavior of the PLLA component. 

Sala M, Kitahara Y, Takahashi S, Fujii T. Effect of atmosphere and eatalyst on redueing bisphenol A (BPA) Emission during thermal degradation of polycarbonate. Chemosphere. 2010 78 42 5. 

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