两亲性共聚物的分子设计与合成及其共混膜性能

从分子结构设计出发,采用自由基聚合、醚化、酯化、原子转移自由基聚合(ATRP)、可逆加成断裂链转移自由基聚合(RAFT)等方法合成了一系列具有不同分子结构(包括接枝、嵌段、交替、超支化等)和链形态(包括直链、梳状、哑铃状、链球状等)的两亲性共聚物,并对这些聚合物进行了谱学表征和性能测试.将这些两亲性共聚物与聚合物膜材料(包括聚偏氟乙烯、聚氯乙烯、聚砜、聚醚砜、聚醚砜酮等)进行溶液共混,通过相转化法制备共混膜,在成膜热力学和动力学分析的基础上,对共混膜的结构和性能进行调控.研究发现,两亲性共聚物在成膜过程中自发地向膜表面迁移富集,并进行自组装,在膜表面形成两亲性共聚物包膜,显著改善了聚合物多孔膜的亲水性和抗污染性能.此外,两亲性共聚物中的功能基团还可赋予共混膜某些功能特性,如生物相容性、环境响应性(pH、温度敏感性)、酶活性等.

Molecular Design and Synthesis of Amphiphilic Copolymers, and the Performances of Their Blend Membranes

Based on molecular dsign,a series of amphiphilic compolymers with different molecular structures and morphologies were synthesized via various methods such as free radical polymerization,etherification,esterification,atomic transfer radical polymerization(ATRP) and reversible addition fragmentation chain transfer(RAFT) polymerization,etc.The synthesis process,reaction conditions,and mechanisms were studied in detail.The structures of the resultant copolymers (including graft,block,alternate and super-branched etc.) were characterized by spectroscopy,and their properties were examined.These amphiphilic copolymers have various morphologies,such as linear,comb-like,dumbbell-like,and chain-sphere-like etc.On basis of the structure characters of the amphiphilic copolymers and polymer membrane materials,the synthesized copolymers were selected and used as additives to prepare blend membranes.The effects of amphiphilic copolymers on membrane structure and properties were investigated detailedly.The hydrophobic chains in amphiphilic copolymers are generally miscible with special membrane materials,while hydrophilic chains provide the blend membranes with enhanced hydrophilicity and fouling resistance.The studied membrane materials in this work include poly(vinylidene fluoride) (PVDF),polyvinyl chloride (PVC),polysulfone (PSF),polyethersulfone (PES),poly(phthalazinone ether sulfone ketone) (PPESK) etc.The structures and properties of the blend membranes were controlled via tuning the thermodynamics and kinetics of membrane-forming systems.It was found that,during the course of membrane formation,amphiphilic copolymer additives accumulated spontaneously and self-organized on membrane surface.The coatings of amphiphilic copolymers on membrane surface promoted notably the hydrophilicity and anti-fouling ability of porous polymeric membranes.Based on these results,a new methodology for membrane modification that "surface modification is achieved by simple blending" was put forward.In addition,the functional groups in amphiphilic copolymers could endow the blend membranes with some special functions,such as biocompatibility,environmental responsivity,enzyme immobilization,etc.