Research on the performance of three-dimensional-braided-glass fiber reinforced in-situ polymerized TPU

In this study, thermoplastic polyurethane (TPU) is prepared by using 4,4′-methylenediphenyl diisocyanate (4,4′-MDI), poly (1,4-butylene adipate) (PBA), and butane-1,4-diol (BDO). PBA as soft segment for TPU. 4,4′- MDI and BDO as hard segment for TPU. The effects of isocyanate index, hard segment content, and soft segment molecular weight on TPU micro-phase separation, molecular weight, and thermal performance are investigated. 3D-Braided-Glass Fiber (GF) reinforced TPU composites are prepared by in-situ polymerized TPU as the matrix resin. Investigation is conducted into how the mechanical properties and microstructure of the composites are affected by the matrix resin TPU’s structural parameters. As the isocyanate index increases, the mechanical properties of the composites first enhance and then weaken, and the interface bonding between TPU and GF gradually deteriorates. Increasing the molecular weight of soft segments has the same trend of change. With the increase of hard segment content, the mechanical properties of the composites are enhanced. The results demonstrate that the mechanical properties of the TPU/GF composites are at their best when the isocyanate index is 1.01, the hard segment content is 43%, and the PBA molecular weight is 2000, with the stretching strength being 289.6 MPa, the impact strength being 141.8 KJ/mm 2 , the bending strength being 183.2 MPa, and the flexural modulus being 10.7 GPa.