可逆加成-断裂链转移自由基聚合法合成梳型磺化聚醚醚酮

Synthesis and Properties of Comb-shaped Sulfonated Poly(ether ether ketone) as Cation Exchange Membrane by RAFT

以带双硫酯取代基聚醚醚酮为大分子链转移剂,采用可逆加成-断裂链转移自由基聚合(RAFT)法合成不同接枝率的磺化聚醚醚酮(g-SPEEK),并对其结构进行表征.在单体/链转移剂/引发剂的投料比(摩尔比)为50∶4∶1,温度为70℃,反应24 h,得到聚合物膜的离子交换容量和吸水率分别为1.312 mmol/g和43.51%,其溶胀率为5.05%,低于Nafion膜的11.50%.热重分析(TGA)结果表明该梳型g-SPEEK具有较好的热力学稳定性,且该聚合物膜具有与Nafion膜相当的抗氧化性.在相同的离子交换容量下,梳型g-SPEEK比主链型SPEEK具有更好的H+离子透过性能.

A series of comb-like sulfonated poly（ ether ether ketone） （ g-SPEEK） with well-defined structures was prepared via reversible addition-fragmentation chain transfer（ RAFT） polymerization using PEEK contai-ning dithiobenzoate as macro RAFT agent and sulfonated styrene（SST） as monomer. The graft rate, chain length and molecular structure were tailored by the molar ratio of SST to RAFT agent and the reaction time of RAFT. The membranes of g-SPEEK were prepared by solution cast. The mixture solvent of water and NMP was used to adjust the membrane morphology. The structure and morphology of g-SPEEK membrane were cha-racterized by Fourier transform infrared spectroscopy（ FTIR） , 1 H NMR, TGA and scanning electron microsco-py（ SEM） . The synthesized g-SPEEK have high hydrophilic/hydrophobic phase separation. With the increase in grafting degree of StSO3 Na, the ion exchange capacity （ IEC ） and water content increase from 0.638 mmol/g to 1.312 mmol/g and 20.19% to 43.51%, respectively. However, its swelling ratio is 5.05% which is lower than that of Nafion membrane（11.50%） . Otherwise, comb-shaped SPEEK has a better H＋ permea-bility than main-chain SPEEK membrane with the same IEC value.