Influence of temperature on the microstructure and mechanical properties of stretched polypropylene. Issue 40 (7th July 2015)

• Record Type: Journal Article
• Authors: Li, Keran; Xiong, Bijin; Cao, Ya
• Is Part Of: Journal of applied polymer science. Volume 132:Issue 40(2015)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2015-07-07
• Subjects: Polymers -- Periodicals; Polymerization -- Periodicals; 668.9
• DOI: 10.1002/app.42622
• Languages: English
• ISSNs: 0021-8995

Abstract

<abstract abstract-type="main"> <title>ABSTRACT</title> <p>Microstructure and mechanical properties of isotactic polypropylene (iPP) stretched at different temperatures were studied. Strain‐induced fibrils were observed after stretching. Crystallinity (<italic>X</italic>_c), crystallite thickness (<italic>L</italic>_c), long period (<italic>L</italic>_pf), and diameter (<italic>D</italic>_f) of fibrils were characterized by Differential Scanning Calorimetry and Small angle X‐ray scattering. <italic>L</italic>_pf of stretched iPP below 60°C was found to be lower than undrawn iPP. <italic>X</italic>_c, <italic>L</italic>_c, and <italic>D</italic>_f increased with increasing draw temperature. Tensile test showed that Young's moduli of stretched iPPs were negatively dependent on <italic>X</italic>_c and <italic>L</italic>_c. The fraction of taut tie molecules was estimated from the mechanical model. Results showed that more tie molecules were formed in the samples stretched at lower temperatures. Dynamical mechanical analysis showed that glass transition temperature was strongly dependent on the draw temperature. The glass transition peak disappeared in stretched iPPs obtained below 80°C. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. <bold>2015</bold>, <italic>132</italic>, 42622.</p> </abstract>