Structure and properties of impact copolymer polypropylene. I. Chain structure

Abstract

ABSTRACT:In this work, impact copolymer polypropylene (ICPP) was fractionated into 4 fractions. ICPP and the 4 fractions were studied using Fourier transform infrared and 13 C nuclear magnetic resonance analysis. The results demonstrate that fraction A is ethylene-propylene rubber, fraction B is ethylene-propylene (EP) segmented copolymer, fraction C is ethylene-propylene block copolymer, and fraction D is polypropylene with a few ethylene monomers in the chain. The differences in properties between different impact copolymer polypropylenes should be due to their fractions' differences in composition and chain sequence structure.

Using Crystallisation Fractionation to Monitor Thermo‐Oxidative Degradation of Impact Poly(propylene) Copolymers

“…An increase in the oxidation induction time with increasing ethylene content is accounted for by the higher chemical stability of its methylene units as well as the barrier effect of the comonomer in intra‐chain hydroperoxide formation 22, 24–26. It is also known that the amount of ethylene affects the morphology of impact PP copolymers, e.g., the shape and size distribution of the dispersed EPR phase as well as the nature of the segmented EP copolymers acting as a compatibiliser at the interface between the EPR inclusions and the iPP matrix 27, 28. This interface has been suggested to play a vital role in the migration and combination of free radicals during the degradation of heterophase EP copolymers 29.…”

The effect of controlled degradation on the molecular characteristics of heterophasic ethylene–propylene copolymers

“…The most common commercial method to produce these polymers is a sequential two stage polymerization of (first) propylene and then copolymerization of propylene and ethylene in the second reactor. The result of this two stage polymerization process is a highly complex mixture of amorphous, random, and blocky ethylene–propylene copolymers with different chemical composition distributions as well as different molar mass distributions, together with highly isotactic polypropylene and some polyethylene homopolymer . It has been proposed that in this complex mixture of morphologies, the ethylene–propylene segmented or blocky copolymers can act as compatibilizers whereby they enhance the interfacial adhesion between random rubbery copolymers and the polypropylene homopolymer.…”

Fractionation and Analysis of an Impact Poly(propylene) Copolymer by TREF and SEC‐FTIR

“…With the realisation of the complexity of the products formed during ICPP synthesis, it has become evident that fractionation techniques would form an integral part of their characterisation. Although ICPP fractions of different crystallinity could be obtained by temperature‐gradient extraction fractionation (TGEF),4, 11, 12 analytical and preparative temperature‐rising elution fractionation (TREF) have become the preferred methods for separation of the different components 2, 5, 7, 13, 14. The combination of TREF and techniques such as 13 C NMR, DSC and FTIR allow for the comprehensive, yet time‐consuming characterisation of ICPPs.…”