Synthesis and characterization of organosilicon functionalized water-based polyvinylidene chloride emulsion with core-shell structure

Abstract

The outstanding barrier performance of polyvinylidene chloride (PVDC) has attracted widespread attention. In this work, a series of organosilicon functionalized water-based PVDC emulsions with core-shell structure are synthesized by seed emulsion polymerization using vinylidene chloride (VDC), methyl acrylate (MA), isooctyl acrylate (EHA) as core and vinylidene chloride (VDC), methyl acrylate (MA) as shell. Vinyl-terminated polydimethylsiloxanes (VT-PDMS) are introduced into the core-shell as modifier. The properties of PVDC emulsions and films modified with VT-PDMS are investigated. On the one hand, when VT-PDMS is properly incorporated into the core-shell particles, the Si-O bonds in VT-PDMS are dissociated, which further forms a cross-networking structure, thereby enhances the adhesion of PVDC film to the substrate. The barrier performance of the film is also improved by a small amount of cross network structure. On the other hand, the addition of VT-PDMS leads to the phenomenon of thin film shrinkage, which further enhances the barrier performance of PVDC. All results indicate that the best comprehensive performance is achieved when the VT-PDMS content in the PVDC core is 2 wt%, the adhesion can be increased to 0.527 MPa, the oxygen transmittance is 5.68 cc/m2·24 hr, and the actual time of water barrier after coating starch-based tableware is over 12 hours. This provides an effective line of thinking for the further application of PVDC barrier film in the field of environmental protection food packaging.