| Polypropylene(PP)is inexpensive and easy to process and is therefore the most widely used universal plastic.However,PP products have high brittleness and poor toughness,especially its low-temperature impact resistance performance is not ideal,thus greatly limiting its further application.Therefore,the toughening modification of PP is the focus of its industrialization and even functional research.The difference in the service life of polymer materials and their natural environment is quite different.Xinjiang is a typical dry and hot climate region,especially in Xinjiang,where the seasonal temperature difference and the temperature difference between day and night are relatively large,and the intensity of ultraviolet light is not uniform,which is different from other regions in China.Therefore,the aging of PP in this environment is very fast.Therefore,it is of great significance to study the aging and anti-aging of PP in dry heat environment in Xinjiang.Therefore,this paper chooses the most widely used spinning grade homopolymer PP raw material in Xinjiang as the research object,and has thermoplastic elastic SBS with wide range of hardness,excellent low temperature performance,good UV resistance and oxidation resistance,etc.The SIS body was blended and modified to study the aging properties of pure PP raw material samples and their blends under dry heat conditions and temperature differences.PP's unique molecular structure and helical conformation result in its easy aging in dry heat,high UV irradiation and high temperature differential climate.According to the indoor and outdoor conditions of dry heat and temperature aging,it was found that the aging degree and speed of pure PP raw materials in the indoor different dry and hot condition aging tests vary with different methods.The greater the temperature difference,the aging of PP samples.The greater the degree,the faster the aging.In the dry-heat pure ultraviolet light aging,the retention of elongation at break of PP specimens aged for only 3 days is less than 50%,which basically loses the use value,especially the UV-313 aging degree is the greatest.The percentage of elongation at break of 60 days exposure to outdoor exposure was only 39.5%,indicating that the degradation of its molecular chain was severe and it completely lost its use value.Based on this,the indoor and outdoor aging rule of PP and the simple aging mechanism were discussed.The thermoplastic elastomer SBS/polypropylene(SBS/PP)blends were prepared by the twin-screw melt blending method.The mechanical properties and low-temperature impact properties of the blends were tested and tested.The ultraviolet light was used for 30 days indoors and the outdoor dry heat environment for 150 days.After exposure to aging,SEM,capillary rheology,XPS,and XRD were used to characterize the morphology and aging properties of the material before and after aging.It was found that the addition of a proper amount of SBS increased the low-temperature impact strength,elongation at break,and the anti-aging properties of PP in a dry heat environment.Adding 20% SBS can improve the low temperature impact strength and elongation at break of blend samples by 10.7% and 29.14%.The addition of SBS can promote the formation of ? crystal form of PP,and the greater the SBS content,the more obvious this effect is.After aging under the temperature difference between indoor and outdoor dry and hot environment,it was found that adding 30% of SBS blends had the best anti-aging properties.Outdoor aging 105 days before the elongation at break was kept below 50% and lost its use value.Heat,oxygen,and other conditions are related to molecular chain breakage.Since the compatibility of SBS and PP is limited afterwards,excessive SBS content will reduce the toughness of the blend.Thermoplastic elastomer SIS/polypropylene(SIS/PP)blends were prepared by the twin-screw melt blending method.The mechanical properties and low-temperature impact properties of the blends were tested and tested.After aging in indoor temperature and 120 days in outdoor dry and hot environment,the blends were aged.SEM,capillary rheology,XPS,XRD and other methods were used to characterize the morphology and aging properties of the material before and after aging.The addition of SIS can improve the low-temperature brittleness of PP,increase the mechanical properties of PP and the anti-aging properties of PP in dry heat environment,but it has no effect on the crystallization performance of PP.Adding 20% of SIS can increase the elongation at break of PP by 39.81%.After aging,the proportion of the blend sample has the best anti-aging property. |
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