摘要:

AbstractRandom copolymers of styrene and methyl methacrylate, prepared by free radical polymerization in bulk at 60°C, were irradiated under vacuum at 35°C with 60Co gamma rays to doses up to 200 Mrad. The flexural strength, with failure occurring in all cases by brittle fracture, decreased with radiation dose; the rate of this decrease increased with increasing methyl methacrylate content. Compressive strength measurements showed a transition from yield to fracture after a radiation dose which increased with styrene content and then a rapid fall in fracture stress for higher doses. Viscometry measurements showed a good correlation between changes in flexural strength and molecular weigh

ISSN:0360-8905    

DOI:10.1002/polc.5070490123

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1975

数据来源: WILEY

摘要:

AbstractPoly(2,2′‐(m‐phenylene)‐5,5′‐bibenzimidazole) (PBI) shows outstanding properties of low flammability, good abrasion resistance, and high moisture regain; but it is susceptible to degradation by sunlight. The chain‐scission quantum yield of 10−5indicates a fundamentally stable structure. Degradation is related to the very intense light absorption in the solar region. Results also show that the degradation route is one of photooxidation. Limitations of traditional methods for preventing photodegradation are discussed, and the possibility of stabilization by a protective coat

ISSN:0360-8905    

DOI:10.1002/polc.5070490124

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1975

数据来源: WILEY

ISSN:0360-8905    

DOI:10.1002/polc.5070490102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1975

数据来源: WILEY