Towards a molecular approach to physical ageing in poly(methyl methacrylate)

✍ Scribed by Pethrick, Richard A.; Davis, William J.

• Book ID: 101226872
• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 258 KB
• Volume: 47
• Category: Article
• ISSN: 0959-8103
• DOI: 10.1002/(sici)1097-0126(199809)47:1<65::aid-pi1>3.0.co;2-9

✦ Synopsis

Physical ageing studies are reported on poly(methyl methacrylate) (PMMA) using positron annihilation lifetime spectroscopy (PALS), dielectric relaxation spectroscopy (DRS) and dynamic mechanical thermal analysis (DMTA). A comparison of the results obtained from these di †erent techniques indicates that the assumption of thermorheological simplicity for physical ageing is most probably questionable. Physical ageing appears to be primarily concerned with a loss in the relaxation strength in the region below the glass transition temperature as monitored isothermally using DRS. Analysis of the "ageing ratesÏ obtained from these three very di †erent types of observation indicates the possibility of a common molecular origin to the processes observed. 1998 ( Society of Chemical Industry