Interphase control in poly(styrene-block-butadiene-block-styrene) copolymer/magnesium hydroxide composites

The role of isostearic acid (ISA) and maleinised polybutadiene (MPBD) in the interphase control of SBS/magnesium hydroxide composites was investigated. Infrared studies showed that both ISA and MPBD interact chemically with the magnesium hydroxide. Flow microcalorimetry studies showed that model polymers that resemble the two phases of SBS (polybutadiene and polystyrene), were absorbed irreversibly on the surface of magnesium hydroxide. Differences in mechanical responses showed that filler surface modification with MPBD led to increased filler-matrix adhesion compared to the composite based on untreated. ISA treatment of the filler led to reduced melt viscosities and filler-matrix interaction, but resulted in higher levels of strain induced crystallization, relative to the composites based on untreated and MPBD treated magnesium hydroxide.