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 (fav). It was found that peel strength of an adhesive is strongly related to the fav 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 fav 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 fav of polyol are desired. Thermal stability of a polyurethane adhesive also improves with uretonimine content.