Synthesis And Application Of PBL@PVA Core-shell Particles

Polybutadiene containing unsaturated double bond in its backbone is anexcellent general purpose synthetic rubber and has wide range of applications in theautomotive, coatings and plastics modification realms. In recent years, Polydiene wasgrafted with vinyl monomer containing polar groups to increase the polarity of thecopolymerization and improve its compatibility with the polymer substrate, and it isan effective method for expanding the application of polybutadiene. In this study,core-shell structure PBL@PVA particles were prepared from the graft polymerizationof Polyvinyl alcohol(PVA) and polybutadiene latex(PBL), then the core-shellparticles were mixed with propylene(PP) to research the influence of the PBL@PVAfelexibilizer on the comprehensive properties such as impact strength of PP, Theabove works have not been reported.This paper focuses on the method of emulsion graft. PVA was grafted onto PBLvia emulsion polymerization using tetraethylenepentamine(TEPA) and tert butylhydroperoxide tert(t-BHP) as redox initiator system.The optical synthesis technology was determined. The graft percentage reached14.52%at70℃for3h,when the weight ratio of PVA/PBL=15/85. Distinct coreand shell structures in the PBL@PVA particles is ovserved by transmission electronmicroscopy(TEM). Characteristic absorption peaks of PVA in PBL@PVA particlesis confirmed by FT-IR. The area of the corresponding peak increases with theincrement of its graft degree. Laser particle size analyzer (LPS) indicates that boththe average particle size and its polydispersity index increases with the increment ofPVA.The effects of content of PBL@PVA particles and dose of the PP-g-MA on thecrystallinity, morphology, mechanical properties and rheological properties of theblend composite were analyzed. The result of DSC indicated that particles of PBL@PVA played a role of heterogeneous nucleating agent in PP. At the same time it caninduce the formation of β-crystal. As a result, the impact strength of the PP blend reached260%. When adding solubilizer PP-g-MA, particles of PBL@PVA werecovered by the PP-g-MA, the role of heterogeneous nucleating and formation of β-crystal are both weakened. SEM showed that the interface between particles ofPP/PBL@PVA and PP had force transmission phenomenon, the composite’s storagemodulus G’, loss modulus G" and the complex viscosity η*of the compositeincreased.