Gelation behaviour during chainwise crosslinking polymerisation of methacrylate resins

Autor:	Peter J. Halley, C. T. Kelly, Mats Johansson, Jakob Lange
Rok vydání:	1999
Předmět:	Gel point Materials science Polymers and Plastics Bulk polymerization Ethylene glycol dimethacrylate Organic Chemistry Dynamic mechanical analysis Methacrylate chemistry.chemical_compound chemistry Polymerization Chemical engineering Polymer chemistry Dynamic modulus Materials Chemistry Prepolymer
Zdroj:	Polymer. 40:5699-5707
ISSN:	0032-3861
DOI:	10.1016/s0032-3861(98)00781-2
Popis:	The gelation process in chainwise crosslinking polymerisation of methacrylate resins with average functionalities of 2.1-50 (1.05-25 methacrylate groups/molecule) was investigated using dynamic mechanical analysis. For all systems a crossover in tan delta (tan delta independent of frequency) was observed at gelation. The gel time was found to decrease with increasing functionality of the system. Within the measured frequency ranges, power law behaviour for the dynamic modulus was observed at the gel point in all systems. A value of the power law exponent n of 0.4 +/- 0.2 to 0.6 +/- 0.1 (increasing with increasing functionality of the system) was determined for gelation during reactions at T greater than or equal to T-g infinity. This trend suggests that the differences in screening between the systems dominate over the difference in fractal dimension. For reaction temperatures below T-g infinity a value of n = 0.3 +/- 01 was obtained, which was attributed to the influence of micro-vitrification. (C) 1999 Elsevier Science Ltd. All rights reserved.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::013601b640146f48d539e89ad793862a https://doi.org/10.1016/s0032-3861(98)00781-2 Zobrazit plný text záznamu Full Text from ScienceDirect