Structure and properties of a β-nucleated polypropylene impact copolymer

Abstract

The effect of a β-nucleating agent (β-NA) on the properties and structure of a commercial impact polypropylene copolymer (IPC) was investigated. The effect of selected β-NAs on the impact resistance, stress and strain behaviour of the IPC is reported. In addition, the IPC was fractionated according to crystallinity by preparative temperature rising elution fractionation. Fractions with varying chemical composition and crystallinity were treated with a two-component β-NA to investigate the effect of the β-NA on the various fractions. The results indicate that the efficacy of the β-NA is dependent on the chemical composition of the polymer that crystallises, more specifically on the sequence length of crystallisable propylene units. The effect of the addition of β-NAs on the overall morphology of the IPC was also investigated, and in particular the size and distribution of the rubbery particles in these complex reactor blends were probed.