Post-crosslinkable thermoplastic polyurethane for control of mechanical properties after processes

Abstract Thermoplastic polyurethane (TPU) has attracted significant attention in various fields owing to its elasticity, abrasion resistance, and processability. However, high-molecular-weight TPUs need to be synthesized to achieve the desired mechanical properties, which generally require the tedious optimization of the synthetic process. Herein, we report a post-crosslinking process by which different types of TPUs with different levels of mechanical properties can be obtained. TPUs containing azide functional groups on the side chain (ATPU) are synthesized with different ratio of azide repeating units to non-azide repeating units, and post-crosslinking is performed via a click reaction using different types (soft and hard) and amounts of crosslinkers (di-alkyne) to adjust the mechanical properties of low-molecular-weight ATPU. The introduction of a soft and hard crosslinker respectively increases the strain and initial modulus. The post-crosslinking method will allow the production of TPUs with different levels of mechanical properties (strain or modulus) using a single synthetic process.