Effect Of γ-irridiation On The Properties Of PA1212/SiC Composite

Owing to its advantages, such as low water absorbtion, good toughness,corrosion resistance, wear resistance, PA1212is widely used in machinery,automobile, military and some other fields. Silicon carbide, known for stablechemical performance, low coefficient of thermal expansion, good abrasive resistance,good rigidity and so on, can be used as filler, which will not only reduce the cost ofproduction but also improve the composite’s mechanical performance.60Co-γ rayirradiation is an efficient way to improve the property of the composite bycrosslinking the polymer chains. Properties of PA1212/SiC composites irradiated by60Co-γ ray are researched in this thesis. The influence of the radiation doses, radiationatmosphere and the content of radiation crosslinking sentisizer TAIC(Triallylisocyanurate) on the mechanical properties, thermal properties and firction wearproperties is investigated. The main content is as follows:(1) PA1212/silicon carbide composites are irradiated by γ-ray. Thecomprehensive mechanical propertie is the best when the content of coupling agent is2.5%. Comparing to the composites without coupling agent, its tensile strength,tensile modules of elasticity, bending strength and flexural modulus are raised about11.9%,28.8%,19.5%and48.7%, respectively. Composites have the best mechanicalproperties when the content of silicon carbide is60%.(2) The properties of composites with different radiation doses are studied.Blending strength and blend molding of the composite are improved about8.80%and11.9%respectively when the radiation dose is200kGy. Testing the properties ofcomposites with different contents of TAIC irradiated, tensile modules of elasticity,blending strength and blending molding of the composite with1%TAIC areimproved about9.63%,12.0%and20.1%compared to the composites without TAIC,and its water absorbtion is the least meanwhile.(3) The wear weightlessness of composites is declining along with the increaseof the radiation doses.Compared to composites without radiation, wearweightlessness of the composite with the radiation dose of200kGy decreased about 18.0%, but the friction coefficient of the composite with the radiation dose of50kGyis minimum.(4) Friction and wear properties of composites irradiated with different radiationatmosphere are tested. The result shows that, comparing to air atmosphere, both of thefriction coefficient and wear weightlessness of the composites prepared in vaccumenvironment decrease.Comparing to dry friction condition, the friction coefficientand weightlessness of the composites tested in water condition deceased about44.4%and63.6%respectively. And the wear surfaces morphology are observed by SEM.(5) Heat distortion temperature measurement shows that, compared to thesample without radiation, a15.7%rise up of the composite with radiation dose of200kGy in HDT is observed.And HDT of the composite containing3%TAICincreases about11.8%.(6) Coefficients of thermal expansion of the composites are detected. It’s foundthat irradiated composite with60%silicon carbide has the least coefficient of thermalexpansion. The coefficient of thermal expansion of the composites decrease graduallywith the increasing of radiation dose when the radiation dose varying from0to200kGy. The composite containg1%TAIC has the lowest coefficient of thermalexpansion.(7) DSC measurement shows that, the crystallization and melting temperaturesof the composite are decreasing along with the increasement of the irradiaction dose.On the contrary, after adding TAIC, the melting and crystallization temperature of thecomposites goes up. Thermal degradation performance of the composites is tested byTG. Initial decomposition temperature and final decomposition temperature of thecomposite are dropping with the increasing of radiation dose.