关键词: 偏氯乙烯, 嵌段共聚物, 多级多孔炭, 中孔, 微孔, 自由基聚合, 纳米结构

Abstract: A series of triblock copolymers consisting of vinylidene chloride polymer and polystyrene (PS) blocks (PS-b-PVDC-b-PS) were prepared via reversible addition-fragmentation chain transfer (RAFT) living radical polymerization, and were further heat-treated to obtain hierarchical porous carbons with micro-and meso-pores directly. The structures of triblock copolymers were characterized with GPC and NMR, and the result demonstrated that the prepared PS-b-PVDC-b-PS exhibited number average molecular weight greater than 6000 and narrow molecular weight distributions (PDI<1.5). The thermogravimetric analysis of triblock copolymers showed two weigh loss peaks, corresponding to thermal degradation of PS and PVDC blocks, respectively. The morphology and pore structure of the resulted porous carbons were characterized with SEM and N₂ absoprtion analysis. PVDC block acted as a good kind of carbon precursor capable of forming micro-pores, and the micro-dispersed PS block acted as a meso-pore extender to generate meso-pores. Carbon yields decreased and average pore diameters increased as the content of PS in triblock copolymers increased. The greatest Brunauer-Emmett-Teller surface area (839 m²·g^-1), mesoporsity degree (54%) and average pore size (2.02 nm) were achieved as triblock copolymer with PS/PVDC molar ratio of 4.3 was used as precursor.

Key words: vinylidene chloride, block copolymer, hierarchical porous carbon, micro-pore, meso-pore, radical polymerization, nanostructure