摘要
Emulsion polymerization conducted in the presence of polymeric emulsifiers is a new strategy to reduce the possible environmental pollution and product performance degradation caused by small molecular emulsifier residue. However, rare literature has reported on the research field of vinyl chloride (VC). This study constructed a facile and efficient VC emulsion polymerization system by utilizing a modified poly(maleic anhydride-co-vinyl pivalate) (PMVP) copolymer as a polymeric emulsifier. Concretely, PMVP copolymer microspheres are synthesized first via self-stabilized precipitation polymerization (2SP) between maleic anhydride (MAH) and vinyl pivalate (VPi). The effects of key reaction parameters, including solvent composition, monomer feed ratios, reaction temperature, and monomer/initiator dosages on the present 2SP polymerization are investigated systematically. As a result, monodisperse PMVP microspheres with tunable particle sizes (Dn, 800–1300 nm), low number-average molecular weight (Mn ∼ 2300 g/mol), and high yield (>90%) are successfully prepared in the methyl tert-butyl ether/n-hexane (m/m = 3:2) mixture solvent, which is screened as the optimal reaction medium. Subsequently, PMVP microspheres are ammonia-hydrolyzed and further applied as effective polymeric emulsifiers for VC emulsion polymerization. Gratifyingly, poly(vinyl chloride) (PVC) emulsion is synthesized successfully with high monomer conversion. The size of PVC latex can be tuned depending on the emulsifier concentration. More importantly, the final emulsion exhibits outstanding colloidal stability against thermal, mechanical force, freeze–thaw, and Ca2+ ions. In summary, this work has successfully constructed a PVC emulsion polymerization by employing PMVP-based copolymers as functional polymeric emulsifiers, offering a promising platform for emulsion polymerization applications.
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