Study On The Preparation And Properties Of PC/ASA Alloy For Vehicle

Plastic alloys are widely used in automotive parts.With the development of automobile industry and market,and the requirements of relevant laws and regulations,the internal quality,appearance quality and environmental friendliness of the plastic alloy for vehicle need higher requirements.In this paper,ASA and PC blend were used to prepare alloys with high strength and toughness.In order to ensure the environmental protection of the materials,improve the quality of the air in the car and reduce the damage to the human body,the requirements for the odor and VOC content of the interior and exterior ornaments of the automobile should be taken into consideration.In order to prepare high gloss and scratch resistant non-spraying plastic alloy,and reduce the spraying process of serious subsequent environmental pollution,it is necessary to improve the apparent black brightness and scratch resistance of the material.This paper studied the influence of PC viscosity,ASA resin content,material ratio and compatibilizer on mechanical properties,flow performance and thermal properties on PC/ASA alloy.The VOC content of PC/ASA system was measured by gas chromatography-mass spectrometry（GC-MS）,and the source and influence factors of VOC in the PC/ASA system were discussed.This study selected Adsorptive reactive deodorant freshener HL-518,Extractive volatiles deodorant freshener LDV2040 as the deodorant of PC/ASA system,to compare the effect of deodorization and analyze the mechanism of deodorization.The effects of PMMA and scratch resistant agent（Polyester grafted silicone and finely grinding SiO₂）on the scratch resistance of PC/ASA/PMMA blends were studied through pencil hardness test,cross grid scratch test and color fastness test.The scratch resistance mechanism of the blends was also analyzed.The results showed that the viscosity of PC,the content of ASA and the ratio of PC/ASA can affect the properties of the alloy.Overall consideration of the mechanical properties,flow performance and thermal properties of the alloy,the low viscosity PC,the ASA containing 20%rubber and the mass ratio of PC/ASA=7:3 were the best.The compatibilization effect of SMA on PC/ASA alloy is better than that of ABS-g-MAH and MBS.When mass fraction of SMA was 4%,the compatibilization effect was the best,and the mechanical and thermal properties of the alloy were improved.From the microstructure of the impact section,the high step and the specific surface area increased,which verified the impact performance improvement。The source of volatile organic compounds（VOC）of PC/ASA alloy was produced by thermal degradation of raw materials and alloy production,and styrene’s abundance was the most,which was the main component of the sporadic substance of PC/ASA alloy.The effect of composition on VOC content of alloy was obvious:The VOC content of the alloy increased with the raise of the amount of ASA added;After the addition of SMA,the VOC content of the alloy increased a little;Antioxidants and Lubricants reduced the VOC content of the alloy,but increased the odor grade of the alloy.The adsorption reaction refreshing agent HL-518 and the Extractive volatiles refreshing agent LDV2040,reduced the content of VOC to a low extent,HL-518 had a good effect on reducing the odor grade of PC/ASA alloy.The processing conditions of the alloy were also the main factors affecting the content of VOC:The content of VOC alloy with extrusion temperature decreased first and then increased,the optimum extrusion temperature of different groups was different;Reducing the screw speed and vacuum was beneficial to the reduction of VOC content;heat treatment was an effective way to reduce the content of alloy VOC,and the optimum condition for heat treatment was 90℃/4h.The scratch resistance of the material was closely related to the surface hardness of the material.The addition of PMMA can effectively improved the surface hardness and gloss of the blends,but when the addition amount was more than 10%,the impact strength and the hot deformation temperature of the blends reduced.The higher the number of PMMA,the higher the change rate of the gloss of the PC/ASA/PMMA alloy before and after the friction,the higher the staining degree of the friction cotton cloth,the worse the wear resistance of the material.Polyester grafted silicone and finely grinding SiO₂ could effectively reduce the friction coefficient of the material surface and they had no obvious effect on the surface hardness of the alloy.However,the chromatic aberration before and after the cross grid scratch test decreased,and the gloss change rate and stain degree of the material before and after the color fastness test decreased,so the scratch resistance of the material increased.finely grinding SiO₂ could improve the scratch resistance of PC/ASA/PMMA system better than polyester graft silicone,but after adding finely grinding SiO₂,the impact strength of the system decreased significantly,and the surface of the material was"foggy",which affected the apparent black brightness.Therefore,polyester graft silicone was more suitable for PC/ASA/PMMA blends.