ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Thermal behavior and degradation mechanisms of three polyester resins, namely bisphenol A based, isophthalic acid based, and general purpose were studied. These resins were cured with styrene in the presence of benzoyl peroxide (BPO) and methyl ethyl ketone peroxide (MEKP) as initiators. The cured resins were studied by thermogravimetric analysis and mass spectrometry. From the thermogravimetric data it was observed that the cured bisphenol-A-based polyester resin was thermally more stable than the cured isophthalic acid-based and general purpose polyester resins. It was also observed that polyester resins cured with MEKP are thermally more stable than benzoyl peroxide-cured products. Thermogravimetric analysis data shows that there are two first-order degradation reactions during thermal degradation in nitrogen atmosphere. The first degradation step involves the scission of cross-links/weak links with the liberation of free linear chains. The second step involves a random scission of the free linear chains into smaller fragments. The framentation patterns of the polyester resins were identified by mass spectrometery. Possible mechanisms for the degradation of the cured polyesters accounting for the experimental observations are discussed.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1989.070370713
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