Synthesis And Properties Of Novel Polyester Thermoplastic Polyurethane Elastomers

In this study,the preparation method of novel polyester thermoplastic polyurethane elastomer(TPU)was studied,and the relationship between the synthesis conditions,composition of TPU and the properties of the prepared TPU was discussed.Firstly,the TPU was prepared by melt two-step method(prepolymer method),and the relationship between the experimental preparation conditions,composition of the raw material and the mechanical properties,weatherability of the TPU were investigated.Secondly,the thermoplastic polyurethane elastomer particles were prepared by water dispersion method.The preparation process of the thermoplastic polyurethane elastomer particles was discussed.The influence factors,the control of the mechanical properties and physical properties of the prepared TPU microparticles were analyzed.The flowability and morphology of the thermoplastic polyurethane elastomer particles were further discussed,which provides the basis for the preparation of polyurethane slush powder.(1)Preparation of thermoplastic polyurethane elastomer using melt two-step method(prepolymer method).Firstly,TPU was prepared by using polyethylene adipate(PEA)or polybutylene adipate(PBA)as the soft block,yellowing resistance of diisocyanate as a hard block,and small molecule diol as the chain extender.The mechanical properties and physical properties of TPU were controlled by adjusting the ratio of-NCO/-OH(R value),catalyst dosage and hard segment content.Secondly,the relationship between the molecular chain structure and the mechanical,physical properties was described.The results show that the prepared thermoplastic polyurethane elastomer has high mechanical properties and crystallinity,which is expected to be used in daily,automobile,leather and other decorative materials.(2)In this part,water is used as the dispersion system,the mixed prepolymer and the chain extender are dispersed in the aqueous medium,and the chain extension reaction under high speed dispersion takes place to form the thermoplastic polyurethane elastomer particles.The polyurethane elastomer particles are obtained by filtration and drying.In this process,the-NCO in the prepolymer reacts with water to produce CO2 and form bubbles.The spherical thermoplastic polyurethane elastomer particles with different diameters are prepared bychanging the process conditions and the particle flow and synthesis mechanism was studied.In the reaction system,the polyester polyol is used as the hydroxyl groups and the excess diisocyanate is used as the isocyanate groups to obtain the isocyanate-terminated prepolymer,followed by mixing with the chain extender and dispersing it in the water dispersion medium to form droplets.Each droplet is used as a minor reaction system to form polyurethane elastomer particles.The results show that the prepared TPU particles have excellent weatherability,mechanical properties and particle mobility,which are expected to be applied to the preparation of thermoplastic polyurethane slush powder.