Study On Preparation Of Polystyrene - N - Phenyl Maleimide By SMA Imidization Method

In this thesis, poly(Styrene-co-maleic anhydride)(SMA) and aniline were usedto synthesize a heat-resistant modifier, poly(Styrene-co-N-phenylmaleimide)(SMI).The amidation and imidization degrees of anhydride in SMA were quantitativelyanalyzed by adopting FTIR, elemental analysis, and potentiometric titration. Thecombined quantitative method is more convenient than literature repotred infraredqualitative analysis and quantitative conductometric titration analysis.In the two-step process for amidation and imidization, the amidation conditionswere optimized by adjusting solvent, reaction temperature, solid content, and molarratio of aniline and anhydride in SMA. The optimal amidation conditions are: solventis tetrahydrofuran; the reaction temperature is50°C; solid content is30%; molar ratioof aniline and anhydride in SMA is1.25:1. Under the optimal amidation conditions,the amidation degree can reach up to90%. In imidization, we mainly focused on theexisting ofrms of polystyrene-N-phenyl maleic acid amide (SNPMA) such as powder,membrane, and solute in the solution on the imidization. It was found that SNPMA inthe solution is most suitable for imidization.We also focused on the one-step process to synthesize SMI in the solutionsystem. The one-step process substantially reduced the production cost. The reactionconditions were optimized by adjusting solid content of the reaction, reactiontemperature, catalyst, molar ratio of aniline and anhydride in SMA. Under the optimalconditions, the total conversion rate for this one-step process reached up to?92%andthermal performance of the as-synthesized SMI was highly improved. In TGA testing,the extended initial temperature of the as-synthesized SMI reached to391.07。C whichis53.88。C higher than that of SMA and13.57。C higher than that of SMI produced byNEC Corporation. Decomposition temperature of the as-synthesized SMI reached to425°C which is50。C higher than that of SMA and25。C higher than that of SMIproduced by NEC Corporation. In DSC testing, Tg reached to224°C which is12。C higher than that of SMA and18。C higher than that of SMI...