J. Yi, E. Keaney, C. Hansen, W. Zukas, J. Mead
University of Massachusetts Lowell,
Keywords: multilayer elastomeric laminates, adhesion, extrusion, chemical resistance
Summary:Multilayer barrier materials for chemical and biological protection suits are currently available, but providing better chemical resistance along with higher flexibility and stretchability is still desired. In this work, three-layer laminates consisting of fluoroelastomer, nitrile rubber, and bromobutyl rubber, were fabricated. Due to the differences in chemical properties of these three elastomers, they do not naturally adhere to one another. Therefore, improving upon their inter-layer adhesion was first studied. It was found that after adding phosphonium salt and N-tert-butyl-2-benzothiazyl sulfonamide (TBBS) into the formulation of nitrile rubber, its adhesion to fluoroelastomer and to bromobutyl rubber was significantly improved. In the next step, compound processing was scaled up from 50g-batch to 1500g-batch compounding via Banbury mixer (size B), followed by rubber sheet extrusion. The processing effects of extrusion speed, temperature, and take-up speed will be discussed. Future work includes the lamination of the extruded elastomer sheets through cohesive vulcanization. The barrier properties of these laminates to chemical warfare agent simulants will then be characterized through standard permeation measurement techniques.