Viscoelastic behaviour of epoxy resins modified with poly(methyl methacrylate)

✍ Scribed by Mondragon, I.; Remiro, P. M.; Martin, M. D.; Valea, A.; Franco, M.; Bellenguer, V.

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 252 KB
• Volume: 47
• Category: Article
• ISSN: 0959-8103
• DOI: 10.1002/(sici)1097-0126(1998100)47:2<152::aid-pi41>3.0.co;2-a

✦ Synopsis

The viscoelastic behaviour of a stoichiometric diglycidyl ether of bisphenol-A, (DGEBA), 4,4@-diaminodiphenylmethanes (DDM)s epoxy matrix modiÐed with several amounts of poly(methyl methacrylate) (PMMA) has been studied by dynamic-mechanical analysis. Mixtures pre-cured at 80¡C ranged from transparency to opacity as thermoplastic content changed from 5 to 15 wt%. These changes have been attributed to variations in the ratio between polymerization rate and phase separation rate when PMMA content increased in the mixtures. When PMMA segregated from the epoxy matrix during curing, it had no inÑuence on the crosslinking density of the epoxy phase. The clear decrease of temperature and activation energy of the b relaxation with respect to those values for the neat matrix, observed for the 5 wt% PMMA-containing mixture but not for the 15 wt% PMMA-containing one, are proposed to be a consequence of physical interactions between the PMMA chains and some epoxy oligomers. The dissimilar variation of the height of the u relaxation with frequency when compared to that for the other relaxations studied, outlines the signiÐcance of physical factors inÑuencing this relaxation.

Society of ( 1998 Chemical Industry