The improvement of heat resistance and mechanical properties of phenolic resin was examined with the blend of novolac and copolymers prepared from p -hydroxyphenylmaleimide (HPMI) and styrene. Copolymers of HPMI and styrene with various molecular weights were synthesized. Glass transition ( T,) an
Studies on modified phenolic resin. Iv: Properties of phenolic resin modified with 4-hydroxyphenyl- maleimide/n-butylacrylate copolymers
✍ Scribed by Akihiro Matsumoto; Kiichi Hasegawa; Akinori Fukuda
- Publisher
- John Wiley and Sons
- Year
- 1993
- Tongue
- English
- Weight
- 796 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0959-8103
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✦ Synopsis
Abstract
Three 4‐hydroxyphenylmaleimide/ n‐butylacrylate (HPMI/n‐BuA) copolymers with different monomer ratios were synthesized. Their average molecular weights, glass transition temperatures (T,~g~), and thermal decomposition temperatures were measured. It was found that these copolymers had higher average molecular weights and higher thermal decomposition temperatures than novolac.
Modified phenolic resins were prepared by transfer moulding from moulding compounds consisting of novolac, the copolymer, hexamethylenetetramine (hexamine), and glass fibre. Properties of the three kinds of modified phenolic resins were examined by flexural test, impact test, dynamic thermomechanometry, and observation of morphology. It was found that phenolic resin modified with HPMI/ n‐BuA (1/3‐6) copolymer and modified with HPMI/n‐BuA (1/7‐0) copolymer showed good toughness and good heat resistance. It was also found that the heat resistance of modified phenolic resins was improved by after‐cure, but the mechanical properties were decreased by after‐cure: similar behaviour was observed for unmodified phenolic resin.
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