接枝聚乙二醇单甲醚侧链制备聚酰亚胺多孔微球

摘要

以3,5-二氨基苯甲酸与线性低聚物聚乙二醇单甲醚在催化剂存在的条件下发生酯化反应,得到了接枝单体。以接枝单体、3,5-二氨基苯甲酸以及均苯四甲酸二酐在非水乳液体系中发生聚合反应,经过两步亚胺化及热处理得到了多孔聚酰亚胺微球。通过实验确定了接枝单体的最优反应条件：酸醇摩尔比为1.3,催化剂、携水剂的用量与醇的质量比分别为4%、130%,反应时间为6h。实验结果表明,随着接枝单体在聚酰亚胺中浓度从20%～40%,粒径逐渐增大,粒径范围为9.5～15.7μm;而玻璃化温度从210℃降至178℃;同时在接枝单体浓度为40%时得到了孔结构,比表面积为148cm3/g;通过控制热处理时气体压力可以控制孔结构大小。%A new graft monomer as new diamine was synthesized by 3,5-diaminobenzoic acid（3,5-DBA） and methoxypolyethylene glycols（MPEG） through esterification reaction in the presence of catalyst.The porous polyimide microspheres was prepared by graft monomer and 3,5-DBA simultaneously with pyromellitic dianhydride（PMDA）in the non-aqueous emulsion polycondensation and then process traditional two steps imidization and the final thermal treatment.The optimal condition of esterification reaction was confirmed by experiments： n（acid）（alcohol） was 1.3,the content of catalyst and water carrying（to PMDA by weight） were 5% and 120% separately and reaction time was 6h.As the concentration of graft monomer in the PI increasing,the size of porous PI microspheres was increasing from 9.5 to 15.9μm;the value of glass transition temperature（Tg） was decreasing from 210 to 178℃.Porous PI microspheres with obvious and uniform porous structure were obtained when the concentration of graft monomer was 40% and the specific surface area was 148cm3/g;the porous size can be controlled by the pressure of the thermal treatment stage in the muffle furnace.