PE-g-PMMA的结晶驱动溶液自组装行为——侧链对片晶形貌的调控

Crystal-driven solution self-assembly behavior of PE-g-PMMA:regulation of side chains

以多羟基功能化的聚乙烯(PE214-g-OH4)为初始聚合物,通过原子转移自由基聚合(ATRP)方法合成了一系列以聚乙烯为主链,以聚甲基丙烯酸甲酯(PMMA)为侧链的无规接枝聚合物(PE214-g-PMMA60、PE214-g-PMMA120、PE214-g-PMMA300),并借助FTIR、DSC、TGA对其结构进行表征.溶液自组装研究表明,在甲苯中,聚合物PE214-g-PMMA120在聚乙烯结晶驱动下先形成厚度约为8nm的单层小片晶,随后融合成厚度不变、直径约为2μm的椭圆形单层片晶;若缩短PMMA侧链长度,依然会形成单核片晶结构,但其厚度增大至10nm;若增加PMMA侧链长度,片晶结构则由单核变为多核,与此同时,其厚度减小至5nm.在上述多核片晶的甲苯溶液中加入不良溶剂(二甲基甲酰胺,DMF),片晶的壳层收缩会导致其结构由多核重新转变为单核.

Using PE214-g-OH4 as the macro-initiator,a series of grafted copolymers(PE214-g-PMMA60,PE214-g-PMMA120,PE214-g-PMMA300)with polyethylene as the main chain and polymethyl methacrylate as the side chains are synthesized by atom transfer radical polymerization(ATRP)method.Their structures are characterized by FTIR,DSC and TGA.The self-assembly behavior of copolymers in toluene is studied.The results show that,driven by crystallization of polyethylene,PE214-g-PMMA120 first forms lamella structure with a thickness of 8 nm.And then larger oval lamellae with a diameter of about 2μm are formed by fusion of the small lamellae.If the length of PMMA side chains is shortened,the lamellae still have single-core structure,but the thickness increases to 10 nm.On the contrary,if the length of PMMA branch chain increases,the thickness of lamellae decreases to 5 nm at the same time,and the lamellar changes single-core to multi-core structure.If N,N-dimethylformamide(DMF/toluene=1:1)is added to the toluene solution,the structure of the multicore lamellae is to be transformed from multicore to mononuclear.