科研之友
微信
新浪微博
Facebook
分享链接
摘要
All glassy epoxy polymers develop macroscopic properties at some degree of conversion. Our selected example, diglycidyl ether bisphenol-A epoxy pre-polymer, was cured with 3,3%26apos;-diaminodiphenylsulfone at stoichiometric equivalents using a series of cure profiles to produce distinct variation in the degree of epoxy conversion and result in varying network and network connectivity. Activation energy of epoxy-amine reaction in this selected system was similar to 61 kJ/mol. The calculated reaction energy barrier was found to vary with the extent of epoxy conversion and is attributed to multimechanistic reactions. Epoxy-amine conversion was tracked in situ via near infrared spectroscopic analysis. A single cure condition (90 degrees C) was selected for experiments focused on preferential linear chain growth and minimal branching and/or crosslinking. The physical properties for matrix materials from samples prepared to varying degrees of conversion were characterized and tested for fracture toughness, tensile, flexural, compression properties, molecular weight between crosslinks/crosslink density, and glass transition temperature(s). An empirical equation was also designed to predict molecular weight between crosslinks based on chemical connectivity and extent of reaction.
- 出版日期2014-9
