Regulating the structure of thermoplastic polyurethane elastomers with a diol chain extender to strength performance

Abstract

The structural defects of thermoplastic polyurethane elastomer (TPU) caused by the uneven distribution of hard segments limiting their potential application in special industrial fields such as aerospace or defense equipment. Optimizing the TPUs' structure is a useful method to adjustable uneven distribution of hard segments and enhance the performance of TPUs. In this work, a chain extender (BMB) embedded in carbamate‐derive units was successfully synthesized by 4,4′‐diphenylmethane diisocyanate (MDI) and 1,4‐butanediol (BDO). Using BMB and as chain extender, a modified BMB‐TPU was prepared, and its properties were systematically evaluated. Compared with conventional thermoplastic polyurethane elastomer (BDO‐TPU), BMB‐TPU had a regular structure with uniform hard segments, narrower molecular weight distribution and stronger intra/inter‐chain hydrogen bonding interactions, and thus better microphase separation. The BMB‐TPU exhibited an excellent tensile strength of 35 MPa, 46% higher than 24 MPa for the control BDO‐TPU. Moreover, the heat resistance of BMB‐TPU was also reinforced compared to BDO‐TPU, with an increase of 7.2°C for the degradation temperature of 5% loss and 9.6°C for the viscous flow transition temperature. We believe our paradigm can provide a feasible guide for designing high‐performance TPUs.

Strength Enhancement of Polyurethane Film by Solution Annealing

“…In recent years, polyurethane (TPU) has attracted more and more attention depending on its excellent mechanical and thermal properties, which are attributed to their molecular composition structure and phase separation morphology of soft and hard segments. − TPU can be widely used in architecture, military, aviation, and other fields, depending on the advantages of molecular structure variability and performance controllability. − The strength of thermoplastic polyurethane is crucial for its wider application, so many methods has been mentioned to improve the strength of TPU. − The depolymerases hydrolyzing lignin partially has been used to synthesize polyurethane elastomers successfully instead of petroleum-derived polyols, the strength and toughness of which have been enhanced obviously attributed to the double cross-linking network structure and interfacial hydrogen bonds . The tensile strength and elongation at break of polyurethane can be controlled by adjusting the proportion of soft and hard segment structures, but performance regulation is limited, and its light transmittance is often difficult to meet the application requirements .…”

Role of the Soft and Hard Segments Structure in Modifying the Performance of Acrylic Adhesives Modified by Polyurethane Macromonomers

“…The hard segments give polyurethanes rigidity, while the soft segments affect the flexibility of the molecular chains . Therefore, by precisely changing the content and type of hard and soft segments, PU materials of different structures and performances can be obtained, with properties such as good wear resistance, oil resistance, flexibility, hardness, and environmental friendliness. − These materials can be used for a wide range of applications, including coatings, adhesives, elastomers, fibers, and rigid materials . Due to the designability of PU, it has also been used in the modification of various materials.…”