Abstract：A cationic amphiphilic macro-RAFT (reversible addition-fragmentation chain transfer) agent, P4VPm-b-PSn-CPDTTC (m=10, 15, 20, 30, n≈6), was synthesized as a surfactant in RAFT emulsion polymerization of styrene. The effects of neutralization degree and length of 4-vinylpyridine block of the agent on the soap-free emulsion polymerization were examined. The results show that a higher neutralization degree results in a longer inhibition period, and a longer 4-vinylpyridine block leads to a shorter inhibition period and a higher polymerization rate. The obtained latex particles have the average diameter of about 40 nm with a very wide range of particle size distribution. On the early stage of polymerization, the number-average molecular weight Mn of the obtained latex agreed well with what was predicted theoretically, but later on, it started to deviate; all of the polydispersity index (PDI) first rose, and then fell. At the end of polymerization, the PDIs were very high, and they increased with the increase of the neutralization degree.
Li Zhengshang,Luo Yingwu. Soap-Free Emulsion Polymerization of Styrene Using Macro-RAFT Agent to Make Cationic Latex[J]. 化学反应工程与工艺, 2013, 29(1): 51-58.
