聚偏氟乙烯-b-聚乙烯基吡咯烷酮嵌段共聚物的制备和结构

Synthesis and structure of amphiphilic poly(vinylidene fluoride)-b-poly(N-vinylpyrrolidone) block copolymers

以C6F13I为链转移剂,通过碘转移乳液聚合制得碘封端的聚偏氟乙烯(PVDF-I),再以PVDF-I为大分子链转移剂进行N-乙烯基吡咯烷酮碘转移溶液聚合,得到聚偏氟乙烯-b-聚乙烯基吡咯烷酮(PVDF-b-PVP)两亲性嵌段共聚物;采用NMR、IR、XRD、DSC和AFM等对PVDF-b-PVP嵌段共聚物的分子和相态结构进行了表征。发现PVP能有效嵌入PVDF与末端碘之间,PVDF嵌段PVP后,PVDF分子链的有序度明显降低,产生γ晶型PVDF,同时结晶温度和结晶度降低。PVDF-b-PVP嵌段共聚物表现微相分离结构,相分离尺寸约20 nm,其亲水性也优于PVDF均聚物。

Iodine terminated poly（vinylidene fluoride） was prepared by iodine transfer emulsion polymerization using C6 F13 I as a chain transfer agent, and further employed to mediate the iodine transfer solution polymerizaton of N-vinylpyrrolidone to prepare amphiphilic poly（vinylidene fluoride）-b-poly（N-vinylpyrrolidone）（PVDF-b-PVP） block copolymers. The molecular and phase structures of PVDF-b-PVP copolymers were characterized by NMR, IR, XRD, DSC and AFM. It is confirmed that PVP block can be effectively inserted between PVDF block and terminated iodine. The order of PVDF chains in the block copolymers was decreased after the incorporation of PVP, resulting the formation of more γ phase PVDF crystals, and the decrease of crystallization temperature and crystallinity degree of PVDF. PVDF-b-PVP copolymers were microphase-separated with a domain size of about 20 nm, and exhibited better hydrophilicity than PVDF homopolymer.