摘要
采用可逆加成-断裂链转移(RAFT)活性自由基聚合制备了聚苯乙烯-b-聚偏氯乙烯-b-聚苯乙烯嵌段共聚物(PS-b-PVDC-b-PS),以此嵌段共聚物为碳前驱体,直接碳化制备微孔-中孔复合多级多孔炭。采用凝胶渗透色谱仪和核磁共振仪表征了嵌段共聚物结构,表明通过RAFT聚合可制得分子量较高(Mn GPC>6000 g·mol-1)和分子量分布较窄(PDI<1.5)的PS-b-PVDC-b-PS。采用热重分析表征嵌段共聚物热解特性,采用扫描电镜、N2吸脱附表征多孔炭形貌和孔隙结构。结果表明嵌段共聚物同时具有PVDC和PS链段的热失重峰,PS链段可完全热解而具有形成中孔的模板作用,PVDC链段热降解形成含微孔的炭骨架,最终形成兼有微孔和中孔的多级多孔炭;随着PS嵌段含量的增加,嵌段共聚物的成炭率逐渐降低,孔隙尺寸逐渐增大;当PS/PVDC聚合度比为4.3时,多孔炭的比表面积、中孔率和平均孔径达到最大,分别为839 m2·g-1、54%和2.02 nm。
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.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2014年第1期358-364,共7页
CIESC Journal
基金
国家自然科学基金项目(21176209)~~
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
vinylidene chloride
block copolymer
hierarchical porous carbon
micro-pore
meso-pore
radicalpolymerization
nanostructure
作者简介
杨杰（1985-），男，博士研究生。
联系人：包永忠。
