Aromatic TPU has better mechanical properties and thermal stability, and aliphatic TPU has better low temperature resistance and yellowing resistance, which can be used to blend with soft PVC to improve the performance of soft PVC.
By using pre polymers were synthesized by aromatic TPU and aliphatic TPU, select good aromatic TPU and mechanical properties of low temperature resistant performance is better aliphatic TPU, adopt the method of mechanical blending, TPU/PVC blend was prepared by thermo-gravimetric analysis, dynamic mechanical properties, resistance to aging test, uv yellowing test and scanning electron microscopy (sem) analysis test TPU effect on the properties of PVC were studied.
(1) the influence of different isocyanate indices and polyols on the performance of aromatic TPU was studied, and the influence of antioxidant on the aging resistance of TPU was discussed.The results show that when R value is 1.05,TPU has better mechanical properties.When the soft segment is PCDL polyol, its mechanical properties are better, and the energy loss is more when the molecular chain moves.When the soft segment is PCDL,TPU has better aging resistance and hydrolysis resistance.When PCDL/PCL is 40/60, the mechanical performance of the TPU is better.
(2) aromatic TPU/PVC alloy was prepared. Firstly, the influence of hardness and different proportions of TPU on blending performance was studied. Secondly, thermal stability, dynamic mechanical properties and aging resistance of blends were studied.The results showed that when the hardness was sool 57A and the blending ratio was 30/70, the blends had better mechanical properties.Aromatic TPU/PVC alloy can improve the thermal stability, deformation resistance and aging resistance of PVC.SEM observation shows that the degree of surface concavity increases with the increase of blending ratio.
(3) the effect of catalyst and IPDI/HDI on the performance of aliphatic TPU was studied.The results show that the synthetic TPU has better mechanical properties and deformation resistance when environmental friendly catalyst is selected.When the amount of catalyst was 0.2%, the mechanical properties of TPU were better, the anti-deformation performance was the best, the degree of microphase separation of the material was higher, the viscosity of the material was higher, and the comprehensive properties gradually decreased with the increase of the amount of catalyst.When the HDI/IPDI ratio increases, the deformation resistance of TPU materials gradually increases. When HDI is used alone, the micro-phase separation degree of TPU is better and the low-temperature resistance performance is better.
(4) aliphatic TPU/PVC alloy was prepared and the effects of two TPU on PVC properties were compared.Aromatic TPU has a great influence on the mechanical properties of PVC. Aliphatic TPU can significantly improve the low temperature resistance of PVC and increase the toughness of PVC.In terms of yellowing resistance, aliphatic TPU has better yellowing resistance, which can improve the color difference change of PVC, while aromatic TPU/PVC blend has a high mechanical strength after ultraviolet light aging.SEM observation showed that aliphatic TPU was dispersed evenly in PVC.
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