Morphological characterization of injection moulded syndiotactic polystyrene

• Published in: Polymer (Guilford) 1995, Vol.36 (12), p.2331-2341
• Main Authors: López, Leonardo C., Cieslinski, Robert C., Putzig, Curt L., Wesson, Rosemarie D.
• Format: Article
• Language: English
• Subjects: Applied sciences; crystallinity; Exact sciences and technology; Injection moulding; Machinery and processing; morphology; Moulding; Plastics; Polymer industry, paints, wood; syndiotactic polystyrene; Technology of polymers
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/0032-3861(95)97330-I

The morphology of syndiotactic polystyrene (s-PS) injection moulded at 50°C and 160°C was examined using polarized optical microscopy, transmission electron microscopy, and Fourier transform infra-red microspectroscopy as a function of mould temperature. A skin/core effect was present and significant structural differences existed at the skin of samples moulded at these two temperatures. Bars moulded at 50°C presented a ‘shish kebab’ morphology at the surface while samples moulded at 160°C had ‘sheaf’ structures. In the sample moulded at 50°C, crystallinity increased from 19% at the surface to 41% at depths >250 μm. Such a gradient was not present in the sample moulded at 160°C, which had 46% crystallinity throughout. This crystallinity gradient in samples moulded at 50°C was responsible for the lower chemical resistance of such samples.