Controlling resin flow in Liquid Composite Moulding processes through localized irradiation with ultraviolet light

• Published in: Polymer composites Vol. 43; no. 11; pp. 8308 - 8321
• Main Authors: Endruweit, Andreas, Matveev, Mikhail, Tretyakov, Michael V.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.11.2022; Blackwell Publishing Ltd
• Subjects: Acrylic resins; Fiber volume fraction; Flow control; Flow distribution; Gels; Inclusions; Irradiation; Liquid composite molding; Liquid Composite Moulding; Photopolymerization; Polyester resins; resin cure; resin flow; ultraviolet light; Ultraviolet radiation; Viscosity
• ISSN: 0272-8397; 1548-0569
• DOI: 10.1002/pc.27001

A vacuum infusion process was implemented to produce composite specimens from a random glass filament mat and an acrylic modified polyester resin curable upon irradiation with ultraviolet (UV) light. Through localized irradiation with UV light during the reinforcement impregnation, the viscosity of the flowing resin was increased selectively. This allowed converging–diverging flow patterns with defined inclusions to be realized and racetracking along reinforcement edges to be suppressed. The approach is based on radical photopolymerisation. Here, the degree of cure and the viscosity of the resin increase under direct irradiation, such that the resin gels and the flow stalls in a matter of seconds, but remain unchanged in areas covered with an opaque mask. While this study is concerned with the feasibility of the process, potential practical applications are in flow control for Liquid Composite Moulding, that is, compensation for local variations in the fiber volume fraction and permeability of reinforcements. The reinforcement is irradiated with UV light during resin infusion. A mask is applied to cover flow paths only. In areas without mask, resin gels and flow stalls when exposed to UV light. Complex flow paths can be realised.