Modification Of Thermoplastic Polyurethane Elastomer

Thermoplastic polyurethane elastomer(TPU)has a good performance on flexibility,oil resistance,ozone resistance and low temperature performance.However,its high cost,lower tensile strength and some other shortcomings limit its applications.How to reduce the cost of TPU and improve its mechanical properties was studied in recent years.In this paper,LDPE/TPU composites and CSW/TPU composites was prepared with low density polyethylene(LDPE)and homemade calcium sulfate whisker(CSW).The effects of LDPE and CSW on the properties of composites was researched.In the research of preparation of CSW in a acidified way at atmospheric pressure,the optimum conditions to prepare CSW and the modification of CSW was studied mainly.The experimental results indicated that CSW can be prepared well when the concentration of calcium oxide was 0.2mol/L,the reaction temperature was 90 ?,stirring speed was 400r/min,dropping speed of sulfuric acid was 2mL/min,soaking time was 40min.The characteristic peaks of calcium sulfate dehydrate appeared in the XRD pattern of CSW with optimum conditions.The CSW has a high purity and a good crystallinity.The aspect ratio of CSW with optimum conditions was between 20 and 60.CSW modified by tetrabutyl titanate or KH550 has a smooth surface and a lower oil factor.And the surface of CSW modified by KH550 was smoother,the oil factor of CSW modified by KH550 was lower than it is modified by tetrabutyl titanate.In the research of preparation of LDPE/TPU composites by melt blending,the effect of contents of LDPE and maleic anhydride-grafted polyethylene(PE-g-MAH)on the compatibility,mechanical properties,crystallization properties and processing properties of composites was studied mainly.The experimental results indicated that PE-g-MAH can greatly improve the compatibility of LDPE and TPU.Hardness,300%stretching strength and crystallization properties of composites increased with the contents of LDPE and PE-g-MAH increased.The impact strength and balance torque of composites decreased with the contents of LDPE increased and increased with the contents of PE-g-MAH decreased.In general,the composites had a best performance when TPU:LDPE equals to 8:2(weight)and the content of PE-g-MAH is 5%.In this condition,the shore hardness was 86A,300%stretching strength was 5.286MPa,impact strength was 22.18kJ/m2,crystallizing temperature was 110.62?,balance torque was 12.7N · m.