The relationship between processing history and the morphology of injection molded toughened polyolefins

• Main Authors: A. Tabtiang, B. Parchana, R. A. Venables
• Other Authors: Mahidol University
• Format: Article
• Published: 2018
• Subjects: Chemical Engineering; Materials Science
• Online Access: https://repository.li.mahidol.ac.th/handle/123456789/26493

The solid-state morphologies of three polyolefins, namely isotactic polypropylene (iPP), isotactic poly(propylene-coethylene) (iPcE), and high-density polyethylene (PE), toughened with an elastomeric poly(ethylene-co-I-octene) (EcO) have been investigated. Morphologies ranged from dispersed droplets with mean diameters in the range 0.2 to 0.6 μm, for iPP, to a fine interpenetrating morphology comprising 17 nm thick lamella crystals and elastomer-rich regions of length-scale 170 nm when the major component was linear PE. In the iPcE formulations. 10 nm thick lamellar crystals of the matrix polymer were observed in the elastomer domains. Dynamic mechanical analysis and microscopy of quenched and annealed samples showed that each system was phase separated in the solid state and in the melt under quiescent conditions, respectively. The differing solid state morphologies were inferred to result from the mixing under melt flow of the partially miscible polymers during processing and by the subsequent liquid-liquid and solid-liquid phase separation on cooling.