Effect of Chain Extender on Adhesive and Optical Properties of Transparent Polyurethane Elastomers

摘要

The adhesion of an optically smooth poly (methyl methacrylate) (PMMA) on different polyurethane has been investigated. A series of transparent polyurethane block copolymers is synthesized and cast into sheet specimens for optical and adhesion evaluation. The segmented polyurethanes were characterized by ultraviolet-visible spectrometry and their tensile properties were determined. A segmented polyurethane derived from 1, 6-hexanediol exhibits better transparency due to its relatively lower crystallinity of the hard segment Adhesion measurements are performed using floating roller method. Adhesion of transparent polyurethanes on polymethyl-methacrylate (PMMA) substrate is found to be limited by a cohesive failure inside the PMMA bulk. XPS and AFM are employed to study the interface and adhesion of the laminates. The mechanism of interfacial adhesion between TPU and PMMA is discussed. The surface properties of the substrates is evaluated and compared by using a contact angle technique. A chemical linkage (through transesterification reaction) may be formed between PMMA and TPU.