Solid-state structure of thermally crystallized syndiotactic polystyrene

• Published in: Journal of applied polymer science Vol. 83; no. 12; pp. 2705 - 2715
• Main Authors: Hodge, K., Prodpran, T., Shenogina, N. B., Nazarenko, S.
• Format: Journal Article
• Language: English
• Published: New York Wiley Periodicals, Inc 21.03.2002; Wiley
• Subjects: Applied sciences; Crystallization; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; polymorphism; Properties and characterization; syndiotactic polystyrene (s-PS); Structure processing relationship; Melt crystallization; Beta form; Crystal form; Styrene polymer; Experimental study; Syndiotactic polymer; Isothermal crystallization; Alpha form; Polymorphism
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.10250

The solid‐state structure of syndiotactic polystyrene (s‐PS) after crystallization from the melt and the glassy state was examined by differential scanning calorimetry (DSC), density, and X‐ray diffraction analysis. It was possible to prepare semicrystalline s‐PS containing either the pure α‐ or the pure β‐crystalline form by melt crystallizing s‐PS from 280 or 330°C. The measurements confirmed the low density of both crystalline forms, which in the case of α‐crystalline form was smaller and in the case of β‐crystalline form was only slightly larger than the density of the glassy amorphous s‐PS. An endeavor to introduce the crystalline phase in s‐PS through cold crystallization at constant temperature above the glass transition resulted in a complex ordered phase. This ordered phase, depending on the crystallization temperature, contained the planar chain mesomorphic phase and the α‐crystalline phase with a low degree of perfection (cold crystallization in the range 120–175°C) or a mixture of the α‐ and β‐crystalline forms with a high degree of perfection (cold crystallization in the range 210–260°C). The combination of DSC and X‐ray measurements enabled us to resolve the complex ordered structure in semicrystalline s‐PS after cold crystallization. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2705–2715, 2002