Effect of cross-linking on rheological properties and a model for flexibility-rigidity transition in SBS/PBMA LIPNs

Abstract

Abstract A series of latex interpenetrating polymer networks (LIPNs) with various cross-linking levels were prepared with polystyrene-polybutadiene-polystyrene (SBS) and butyl methacrylate (BMA) by emulsion polymerization. The gel content of the resultant latex particles ranged from 13.2% to 90.8%, with the amount of cross-linking agent increased. The structural, thermal and rheological properties of the latex particles were investigated by laser particle analysis, transmission electron microscopy, Fourier transform infrared spectroscopy, gel permeation chromatography, thermogravimetric analysis, differential scanning calorimetry and torque rheometry. Furthermore, in order to study the effect of gel content on the flow properties, a model is shown to predict the existence of a flexibility-rigidity transition of SBS/PBMA LIPNs as the amount of cross-linking agent increased. Torque data were interpreted in terms of shear rate, shear stress and viscosity. The relationship between gel content of SBS/PBMA LIPNs and polyvinyl chloride compositions and their effect on plasticization performance were determined, and the predictions of the model have good agreement with their flexibility-rigidity transition.