Characteristics of polyurethane adhesives with various uretonimine contents in isocyanate and average alcohol functionalities

Polyurethane adhesives are found in a variety of applications. To ensure durability and functionality, a polyurethane adhesive is required to possess good adhesive properties and thermal stability. In this study, polyurethane adhesives were fabricated using isocyanate and polyols of various type and functionality ( f av ). It was found that peel strength of an adhesive is strongly related to the f av of a polyol and uretonimine content. At high uretonimine content, the probability of forming hydrogen bonded component increases and as a result the adhesive's peel strength increases. At high f av and molecular weight of a polyol, an adhesive's wettability decreases so does its adhesion to a substrate. Therefore, designing for a functional adhesive, high uretonimine content and low f av of polyol are desired. Thermal stability of a polyurethane adhesive also improves with uretonimine content. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 43737.