Polypropylene nucleation on a glass fibre after melt shearing

• Published in: Journal of materials science 1992-11, Vol.27 (22), p.6047-6052
• Main Author: MONASSE, B
• Format: Article
• Language: English
• Subjects: Applied sciences; Composites; Exact sciences and technology; Forms of application and semi-finished materials; Polymer industry, paints, wood; Technology of polymers
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/BF01133748

Thermoplastic composites may exhibit a wide range of crystalline morphologies in the neighbourhood of fibres. It was found that glass fibre shearing of a molten polypropylene at high temperature modifies the subsequent isothermal crystallization (T sub c = 122 deg C) under static conditions. The crystallization results have been analysed as a function of the previous high temperature, shear, gamma , shear rate, gamma ', and shear stress, tau . The mechanical parameters at high temperature, gamma , gamma ', tau , have been calculated for two shearing temperatures (T = 170, 210 deg C) and two fibre displacements. An alpha -phase nucleation process took place at the fibre surface after shearing at the higher temperature (T = 210 deg C). The nucleation increased with shear but did not appear for static conditions. A strong nucleation process in beta phase appeared on the fibre surface after shearing of the polymer at the lower temperature (T = 170 deg C). These strong morphological modifications with shearing temperature have been analysed as a function of mechanical and thermodynamical parameters.