High Ortho Phenyl Ether Type Phenolic Resin Synthesis And Ammonia-free Molding Compound Applied Research

Phenolic resin and phenolic moulding compounds (PMC) is the earliest-developed and widely-used resin and composites, respectively. With the development of technology, resin and PMC with higher performance are required in industries. In PMC field, traditional PMC prepared with two-step method use hexamine (HTMA) as the curing agent, which will release the gas of ammonia and nitrogenous compounds in the curing process. For electrical elements with metallic insert or other high-grade molding articles, ammonia gas that released from the articles will lower the quality level and shorten the service lifetime. Therefore, developing and producing ammonia-free PMCs is becoming industrial hot spot. Usally Resole resin is used for ammonia-free PMCs in present domestic market, which has processing drawbacks such as roll banding, and mold sticking, leading to obviously deteriorated production efficiency and quality of products. In order to overcome these problem, high-ortho phenolic resin with zinc acetate as the catalyst have been used, but this kind of resin needs long reaction time druing the production, resuting in low production efficiency, and thus can't meet the production requirements. Based on the importance and problems of high-ortho phenolic resin and related ammonia-free PMC, this thesis reportes our research on the synthesis of high-ortho phenolic resin, and the investigation on the composition and manufacturing process of corresponding ammonia-free PMC with attractive process-feasibility. The thesis includes three parts:First, with zinc acetate as catalyst research the effect of the factors such as formalin concentration, catalyst dosage, dehydration process parameter, solution on the polymerization reaction. The results show that all the factors have the influence on the reaction, and the reaction time will shorten dramatically with high concentration fomalin.Then, discuss the reaction mechanism of hi-ortho resin in this part, optimize the dehydration process and select suitable solvent for the resin, finally synthsize the phenolic resin solution with feasible process, which can meet PMC's technological requirements. Second, study the curing bahaviour, structure and properties of the hi-ortho resin by FTIR, GPC, DSC and make the comparison with regular Novolac, Resole resin to provide the basic for the development of high performance phenolic resin.Finally, with the hi-ortho phenolic resin and regular Resole resin as matrix develop the free-ammonia PMC by wet process, discuss the feasibility of two kinds of resin for PMC and investigate the influence of PMC recipe, manufacturing process on the free-ammonia PMC's properties, then optimun proportion of the components in the recipe and the optimal process is determined. the results show that with hi-ortho phenolic resin developed in the thesis as matrix, hi-performance PMC with low free ammonia content, higher compositive properties than regular PMC can be made.