Accessing photo-based morphological control in phase-separated, cross-linked networks through delayed gelation. (June 2015)

• Record Type: Journal Article
• Authors: Szczepanski, Caroline R.; Stansbury, Jeffrey W.
• Is Part Of: European polymer journal. Volume 67(2015:Jun.)
• Page Start: 314
• Page End: 325
• Publication Date: 2015-06
• Subjects: Photopolymerization -- Heterogeneous polymers -- Phase separation -- Kinetic control; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; Polymerization; Polymers; Periodicals; Electronic journals; 547.705
• DOI: 10.1016/j.eurpolymj.2015.04.006
• Languages: English
• ISSNs: 0014-3057

Abstract

Abstract : Graphical abstract: Highlights: We explore phase separation in a comonomer matrix modified with linear polymer. The ratio of comonomers is varied to increase diffusion during phase separation. Heterogeneous morphology is controlled with photo-irradiation intensity. Increasing irradiation intensity decreases heterogeneous domain size. Phase separated morphology is formed under very rapid polymerization conditions. Abstract: This work presents an approach to extend the period for phase separation, independent of temperature, in ambient phase-separating photopolymerizations based on the copolymerization of structurally similar mono- and di-vinyl monomers. Copolymer resins composed of triethylene glycol dimethacrylate (TEGDMA) and ethylene glycol methyl ether methacrylate (EGMEMA) were modified with a thermoplastic prepolymer, poly(butyl methacrylate). With increasing EGMEMA modification into the bulk TEGDMA resin, there is a decrease in the initial reaction rate, which increases the time for development of compositionally different phases prior to network gelation. The period between phase separation and gelation was probed through optical and rheological measurements, and it was extended from 22 s in a TEGDMA resin to 69 s in a TEGDMA:EGMEMA copolymer, allowing these materials to be processed under a wide range of UV-irradiation intensities (300 μW cm −2 –100 mW cm −2 ), which provided an additional degree of control over the resulting phase separated domain size and morphology.