Non-isothermal curing kinetics and thermal properties of benzoxazine-phenolic copolymers
来源期刊：中南大学学报(英文版)2009年第3期
论文作者：徐丽 司徒粤 胡剑峰 曾汉维 陈焕钦
文章页码：392 - 398
Key words：benzoxazine; novolac-type phenolic resin; copolymer; cure kinetics; thermal degradation; Ozawa method; crosslinking
Abstract: Using novolac phenolic resin, aniline and formaldehyde as raw materials, benzoxazine-phenolic copolymers with different percentages of benzoxazine rings were prepared. FT-IR was adopted to characterize the molecular structure of the novolac-type phenolic resin and the benzoxazine-phenolic copolymer BP31. In order to understand the curing process of the copolymers, the curing behavior and curing kinetic characteristics were studied by differential scanning calorimetry (DSC), and the catalytical effect of phenolic hydroxyl on the curing behavior of copolymers was investigated. To investigate the thermal properties of this resin, the thermal degradation behaviors of the cured samples were studied by thermal gravimetric (TG) method, and glass-transition temperatures (Tg) of the cured copolymers were also evaluated by DSC. The dynamic Ozawa method was adopted to determine the kinetic parameters of the curing process as well. The activation energy is 78.8 kJ/mol and the reaction rate constant is in the range from 40.0 to 5.2 (K/min)n according to reaction temperatures. The Ozawa exponent decreases from 2.4 to 0.7 with the increase of reaction temperature, and curing mechanism is expounded briefly according to the results. TG result shows that the highest char yield of copolymers is 50.3%. The highest Tg of copolymers is 489 K, which is much higher than that of pure benzoxazine resin.
基金信息：the Key Science and Technology Item of Guangdong Province, China
