Impact of oligoether chain lengths on the relaxation processes in poly(oligo(ethylene glycol) methyl ether methacrylate) networks that are synthesized by radiation-induced crosslinking polymerization. (May 2020)

• Record Type: Journal Article
• Authors: Czaderna-Lekka, Anna; Piechocki, Krzysztof; Kozanecki, Marcin; Okrasa, Lidia
• Is Part Of: Journal of physics and chemistry of solids. Volume 140(2020)
• Publication Date: 2020-05
• Subjects: Poly(oligo(ethylene glycol) methyl ether methacrylates (POEGMAs) -- Molecular relaxations -- Polymer network -- Oligoether chain -- Dielectric spectroscopy; Solids -- Periodicals; Solides -- Périodiques; Solids; Periodicals; 530.41
• DOI: 10.1016/j.jpcs.2020.109359
• Languages: English
• ISSNs: 0022-3697

Abstract

Abstract: The molecular mobility in poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) networks with varying side chain lengths ( n = 2–19 oxyethylene groups), which are synthetized by radiation-induced crosslinking polymerization, has been investigated by dielectric spectroscopy. A complete relaxation map for these materials with four processes was created for the first time. At higher temperatures, α relaxation corresponding to the dynamic glass transition and α' relaxation, which was likely correlated with sub-Rouse processes, were found. Below the dynamic glass transition, two Arrhenius-type processes were distinguished: the γ -process, which was assigned to the end (methoxy-) group; and weak β -relaxation, which was dependent on the oligoether chain length and was related to side chain movements. The fragility index for all of the POEGMA networks proves that these are strong glass-forming materials. In the partially crystalline samples with n > 7, the relaxation processes are strongly disturbed by cold crystallization and melting. Graphical abstract: Image 1 Highlights: Molecular mobility in POEGMAs with various side chain lengths was analyzed. DRS was used to examined dried POEGMAs networks produced by RI-CP. Complex relaxation map with four processes was given for the first time. Two patterns of behavior may be distinguished – amorphous and semi-crystalline networks.