烷基化程度对N-十八烷基化聚乙烯亚胺梳状高分子结构的影响  

EFFECT OF ALKYLATION DEGREE ON THE STRUCTURE OF N-OCTADECYLATED POLYETHYLENEIMINE COMB-LIKE POLYMERS

作　　者：石海峰[1,2] 尹亿平[1] 张兴祥[1] 王笃金[2] 

机构地区：[1]天津工业大学中空纤维膜材料与膜过程国家重点实验室培育基地天津市改性与功能纤维重点实验室功能纤维研究所,天津300387 [2]中国科学院化学研究所北京分子科学国家实验室工程塑料院重点实验室,北京100190

出　　处：《高分子学报》2013年第1期56-62,共7页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号20904040;21174105);天津市自然科学重点基金(基金号12JCZDJC26800)资助项目

摘　　要：利用烷基化方法制备了烷基化取代程度(DS)介于47%～17.6%的N-十八烷基聚乙烯亚胺(PEI18C)梳状高分子.通过红外光谱、差示扫描量热法(DSC)、X-射线衍射和热失重分析等方法研究了PEI18C梳状高分子的结构、结晶行为和热稳定性,探讨了侧链烷基DS对C18侧链结晶及临界结晶行为的影响.结果发现,随DS的降低,PEI18C梳状高分子的结晶度由54.0%降至20.3%,可结晶碳原子数目由11.4个降到4.3个.受限于PEI骨架上C18烷基侧链的堆积排列模式并没有发生根本变化,仍以六方晶胞的形式进行排列.结果表明,侧链烷基DS或沿主链的侧链烷基分布密度对梳状高分子的结晶行为和临界结晶能力有明显的影响.从侧链结晶的角度,分析了侧链烷基取代度对梳状高分子结晶及热稳定性的影响.N-octadecylated polyethyleneimine （PEI18C） comb-like polymers with different substitution degrees （DS） ranging from 47%~17.6% have been successfully fabricated through alkylation technique.The structure,crystallization behavior and thermal stability of PEI18C comb-like polymers with different DS had been systemically characterized by Fourier transform infrared spectroscopy （FTIR）,differential scanning calorimetry （DSC）,wide-angle X-ray diffraction （WAXD） and thermogravimetric analysis （TGA）,and also the effect of DS on the side-chain crystallization and the critical crystallization phenomenon of C18 side groups grafted along PEI backbone were also deeply investigated.The results show that the degree of crystallinity and the number of crystallizable carbon atoms in the C18 side chains of PEI18C comb-like polymers decreased from 54% to 20.3%,and from 11.4 to 4.3,respectively,with the DS decreasing from 47% to 17.6%.In the meantime,the packing mode of confined C18 side groups along PEI molecules display the same manner regardless of the variation of DS,and C18 side groups also take the hexagonally packed structure.The results further demonstrated that the degree of substitution of side alkyl groups or the dispersion density of side groups along polymeric backbones also acts as an important role in the aspect of controlling the side-chain crystallization and the critical crystallization behavior of comb-like polymer,besides the lengthscale of side alkyl chains and the rigidity of polymeric main chains.And,the crystallization behavior and thermal stability of comb-like polymers with different DS are further discussed from the viewpoint of side-chain crystallization.

关 键 词：梳状高分子 聚乙烯亚胺 结晶 侧链烷基 

分 类 号：O631.3[理学—高分子化学]