Isotactic polypropylene crystallized from the melt. II. Thermal melting behavior

✍ Scribed by Ismail A. Al-raheil; Ali M. Qudah; Mohammed Al-share'

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 174 KB
• Volume: 67
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19980214)67:7<1267::aid-app16>3.0.co;2-z

✦ Synopsis

Isotactic polypropylene (iPP) isothermally crystallized from the melt was studied by differential scanning calorimetry (DSC) and light transmission measurements techniques. When samples crystallized isothermally above 132ЊC, a-spherulites were formed only; the DSC measurements showed double melting endotherms peak. The first peak represents the melting of crosshatched lamellae in a-spherulites, while the second peak is correlated to melting of the radial and the reorganized tangential lamellae. Below 132ЊC the iPP showed a broad melting peak endotherm with a melting tail endotherm at the low temperature side. The light transmission measurements showed that the tail endotherm is due to the melting of b-spherulites and the broad melting peak is due to the melting of a-spherulites.