Effect of Hard Segment Content on Adhesion and Mechanical Properties ofThermoplastic Polyurethane Adhesives

Due to their versatile applications, there is currently a need for flexible thermoplastic polyurethane(TPU) adhesives that can be developed considering the availability of the raw materials. In thisresearch, TPU adhesives were synthesized using a polypropylene glycol with a higher-than-usualmolecular weight, i.e., ۴۰۰۰ g/mol, and ۴,۴՛-diphenylmethane diisocyanate, both produced bynational companies. The effect of hard segment content was investigated on the adhesion andmechanical properties of the adhesives by lap-shear and tensile tests. The lap-shear strength of theadhesives increased from ۹۵.۵ to ۱۹۲.۷ kPa with an increase in the hard segment content from ۱۷%to ۲۱%. The tensile strength and Young’s modulus of the adhesives also improved from ۴.۳ to ۸.۸and from ۰.۱ to ۶.۹ MPa, with strains at break of above ۸۰۰%, guaranteeing their flexibility. Thestudy revealed that the desired properties of these TPU adhesives can be tuned for a wide range ofapplications, from pressure-sensitive to rubbery solution adhesives.

کلیدواژه ها:

Adhesive ، Polyurethane ، Hard Segment Content ، Lap-Shear Strength ، Tensile Strength