Influence of aliphatic and aromatic isocyanates on the properties of poly(ether ester) polyol based PU adhesive system

This study has been conducted with an emphasis to develop a biobased polyol from canola oil by transesterification reaction followed by epoxidation and ring opening reaction with an intention to insert hydroxyl group at unsaturation sites. The products obtained were characterized by nuclear magnetic resonance and FTIR spectroscopy for structural analysis and to determine the extent of reaction. Furthur, the studies have been conducted on different Polyurethane (PU) adhesives obtained by reacting this resulted canola oil based polyether‐ester polyol and various kinds of aliphatic or aromatic diisocyanates commercially available, i.e., Methylenediphenyldiisocyanate (MDI), Toulenediisocyanate (TDI), Isophoronediisocyanate (IPDI), Hexamethylenediisocyanate (HMDI) with a purpose to examine their influence on adhesive properties such as green strength, curing time, gel time, lap shear strength. The properties of resulted polyurethanes had shown considerable (or prominent) variation in their behavior particularly in terms of thermal stability, adhesion strength, corrosion resistance, etc. The synthesized adhesive showed much better performance as compared to commercially available adhesive formulation under different conditions of testing. The thermal stability of PU adhesive formulation were analyzed and compared by thermogravimetric analysis. POLYM. ENG. SCI., 58:112–117, 2018. © 2017 Society of Plastics Engineers