Electron spin resonance study on chemical crosslinking reaction mechanisms of polyethylene using a chemical agent. V. Comparison with polypropylene and ethylene-propylene copolymer

✍ Scribed by T. Yamazaki; T. Seguchi

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 211 KB
• Volume: 38
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/1099-0518(20000915)38:18<3383::aid-pola170>3.0.co;2-m

✦ Synopsis

We studied the chemical reaction process of polypropylene (PP), ethylenepropylene copolymer (EPM), and ethylene-propylene-diene copolymer (EPDM) crosslinking induced by dicumyl peroxide (DCP) using electron spin resonance (ESR).

Free radicals appeared at an elevated temperature of around 120 °C and the behavior and kinetics of the reaction process were observed at 180 °C. The radical species detected in PP were alkyl type radicals, formed by the abstraction of hydrogen atoms from the tertiary carbon of polymer chains. For EPDM containing a diene component, the radicals were trapped at double bonds in this diene component to form allyl radicals. The resolutions of these spectra were extremely clear; hence, isotropic spectra of these polymer radicals were obtained. We measured the ESR at high temperatures and confirmed that the process of crosslinking induced by DCP was a free radical reaction.