The HDPE/TPUs Of Blending And Their Effect Of γ-Radiation

In this work, the blends with different ratios of high-desity polyethylene /thermoplastic polyurethane (HDPE/TPU) were prepared through melt mixing by using a twin-screw extruder, with EVA-g-MAH (mEVA),POE-g-MAH (mPOE), PN1 and PN2 (which were made by our own laboratory ) as compatibilizers.γ-Radiation treatment of different doses (D≤25kGy) was applied to the blends for the first time. The effect of they-radiation and compatibilizer on their mechanical properties,thermo properties,rheological behavior,structure and morphology were systematically investigated.HDPE and TPU are immiscible, The mechanical property of simply blended HDPE/TPU could be improved through they-radiation at modest radiation dose (D) and the introduction of the compatibilizer, and their strength,rigidity and toughness of the blends were improved greatly. In the HDPE/TPU(90:10) blends EVA-g-MAH performanced better in improving the notched Izod impact strength than other compatibilizers used in the experiment . The notched Izod impact strength of the HDPE/mEVA/TPU was gradually enhaanced with the increase of compatibilizer content in the mEVA range from 2 to 10 phr. While PN2 was better than other compatibilizers in improving the tensile strength and the modulus. In the TPU /HDPE (90:10) blends the ability in improving the machanical properties is ranked in a decreasing order as POE-g-MAH > PN1 > EVA-g-MAH >γ-radiation. In the rang of 2～10phr, it was enough to improve the compatibility of the blend when POE-g-MAH was introduced about 2phr.It was showed that the the glass-transition-temperature (T_g) and dynamic storage modulus (E') of TPU/POE-g-MAH/HDPE were higher than that of TPU/HDPE by DMA. The T_g was increased and E' was affected little byy-radiation for TPU/HDPE blends.After compatibilizers was added, T_m,△H_m and△H_C of HDPE/TPU (90:10) blends were increased , and the crystalline ability of the blends was improved. Tm, △H_m,△H_C was increased in TPU/HDPE(90:10) blends with EVA-g-MAH as compatibilizer than that of TPU/HDPE(90:10) blend. Because of the introduction of POE-g-MAH or PN1 to TPU/HDPE blend,△H_m,△H_C were decreased. After 10kGy'sγ-radiation△H_m and△H_c were decreased, while T_c was increased.HDPE was formed into small crystallite in HDPE/compatibilizer/TPU blends and the elastomer dispersed among the crystals in the form of particles. The size of crystallite was decreased with the increase of the content of compatibilizer. Compared with the HDPE/TPU blend, HDPE's crystals in HDPE/compatibilizer/TPU blend were smaller.SEM was indicated that the introduction of compatibilizer orγ-radiation could enhance the interaction between HDPE and TPU in the blends, and improve the compatibility between HDPE and TPU.The melt flow rate (MFR) of HDPE/compatibilizer/TPU was decreased with the increase of the compatibilizer content, and it was decreased more remarkably afterγ-radiation.HDPE/mEVA/TPU blends all represented a pseudo-plastic fluid flow character. The apparent viscosity of HDPE/TPU and HDPE/mEVA/TPU melt decreased with the increase of shear rate, shear stress and the rise in temperature respectively, the apparent viscosity of blend was affected little by the content of EVA-g-MAH. But the viscous flow activity energy of HDPE/mEVA/TPU blend decreased because of the introduction of the mEVA compatibilizer.