| Acrylonitrile-butadiene-styrene (ABS) is a synthetic resin widely used in the automotive and home appliance industries. With the constant improvement of market demands for home appliances with diversified product performance, plastic products with surfaces featuring high glossiness, wear resistance, and impact require secondary processing by spraying and grinding. However, these processes waste manpower and resources, and contradict green manufacturing. Therefore, the development of green polymeric materials that can meet the demand of product diversification has attracted considerable attention. Developing a new polymer material is time consuming and difficult. ABS blending modification produces polymer materials with excellent properties. ABS/polymethyl methacrylate (PMMA) is a glossy green blend resin widely used in the home appliance industry, especially in shell application, because of its excellent comprehensive performance. Increasing the content of PMMA increases glossiness but decreases toughness, which limits the application of this material. As a structural material, the strength and toughness of polymer are two important mechanical properties.So the polymer toughening modification has been the important hot topic in the field of polymer material science.Few studies at home and abroad have focused on ABS/PMMA alloy because of its poor toughness. Thus, improving the toughness of ABS/PMMA alloy and determining the different factors influencing the toughnessand glossiness of the alloy are important to design high-glossiness and high-toughness ABS/PMMA blend.. The results of this study have important theoretical significance and engineering application value. This study received grants from the National Science and Technology Support Program (2011BAF16B01) "Advanced Injection Molding Technology and New Mould Structure Development and Application Promotion" and from the Development of Science and Technology Plan Projects of Weihai (2015GGX030) "Highlights of the Preparation and Properties of ABS Resin Improvement." Modification research on the ABS/PMMA blend system obtained the following results:(1) Response surface methodology was performed to analyze the effects of blending parameters on the toughness and glossiness of ABS/PMMA alloy. Ethylene-methylacrylate (EMA) as an elastomer toughening agent was also evaluated. Results showed that the component content of EMA significantly affected the impact strength and surface glossiness of the alloy. The impact strength increased but the surface glossiness of the alloy decreased with increasing EMA content. The parameters of the blending process were optimized to obtain the best impact strength and surface glossiness of the alloy. The effects of different blending sequences of the ABS/PMMA/EMA alloy on toughness and glossiness were also investigated. Results showed that the blending order affected the glass transition temperature of the alloy and the compatibility between different phases. When ABS, PMMA, and EMA were blended simultaneously, maximum tensile strength was achieved because of the compatibility of the alloy. Moreover, the phase interface binding force was stronger, and the rubber particles can effectively transfer the axial tensile force. Optimal impact toughness was achieved in the absence of a notched impact experiment and when ABS, PMMA, and EMA were blended simultaneously. The fracture surface showed a high stress concentration, and the shear yield of the matrix was also high. In the v-notch impact experiment, PMMA and EMA were blended first, followed by the addition of ABS. Under this condition, the impact strength and surface glossiness of the alloy were the largest. The main reason is PMMA and EMA had smaller particle sizes and had a more uniform distribution after two extrusions, which improved the compatibility between phases.(2) The screw rotation speed was controlled to obtain different rubber particle sizes. The effects of the rubber particle size of ABS/PMMA, core-shell toughening agent, and modifier methacrylate butadiene styrene (MBS) on the touheness and glossiness of the ABS/PMMA/MBSternary blend system were analyzed. An ABS/PMMA blend system matrix with multiple craze was achieved when the rubber particle size of Dw was 0.22 ?m. However, large rubber particles caused the instability of the craze, causing expansion and then cracking. After adding MBS flexibilizer, the rubber particle size of the ABS/PMMA/MBS blend system decreased. The rubber particle diameter distribution domain ranged from 0.21 ?m to 0.23 ?m, but the impact strength of the alloy increased. SEM observation revealed that the fracture surface stress concentration increased. With increase in the yield deformation matrix, the addition of MBS exerted a toughening effect on the ABS/PMMA blend system. With the decrease in rubber particle size, the glossiness of the ABS/PMMA blend system improved, but when the sizes of the Dw rubber particles were less than 0.2 ?m, the glossiness declined. For the ABS/PMMA/MBS blend system, the overall glossiness declined because the rubber particles in MBS made matching the rubber particles with the refractive index difficult.(3) nano-SiO2 was chosen as a modification agent, and its phase distribution in the ABS/PMMA blend system was studied. The effect of nano-SiO2 content on the mechanical properties of the ABS/PMMA alloy was investigated. The ratio of two types of ABS/PMMA interface interaction parameter B was calculated. The bond strength between the nano-SiO2 filler particles and the matrix interface increased, and the tensile strength of the alloy was enhanced. With the increase in nano-SiO2 content, the impact strength of the ratio of the two types of alloy declined. Choosing different types of modifier changes the nano-SiO2 and ABS/PMMA interface bonding state. The addition of stearic acid-modified nano-SiO2 blend decreased the tensile strength and increased the impact strength of two types of alloy. The reason is that the stearic acid-modifiedimproved the dispersion of nano-SiO2 and reduced the agglomeration of nano-SiO2 particles. The addition of coupling agent KH570, due to the increase of nano-SiO2 agglomeration phenomenon, decreased the tensile strength of the alloy, but the impact strength of the modified polymer was higher than before the modification. nano-SiO2 reduced the surface glossiness. With stearic acid addition and coupling agent modification, the surface glossiness ofternary blend decreased even more.(4) On the basis of the homogenization theory and surface-based cohesive methods combined with the finite element software Abaqus/Explicit ABS/PMMA/nano-SiO2, a representative volume element model was obtained. At the mesoscopic level, the influence of ABS/PMMA/nano-SiO2 on macroscopic mechanical behavior was studied. Before adding nano-SiO2, ABS/PMMA, damage occurred at the first junction in the rubber particles and matrix interface. Tensile stress in the maximum stress area, from inside the rubber particles, gradually extended along the equator because of the axial stress superposition effect of the adjacent rubber particles, further causing the deformation of adjacent rubber particles. Moreover, the addition of nano-SiO2 significantly changed the evolution of stress, strain, and damage of blend. Under the same bonding interface design, before the addition of nano-SiO2 particles to the rubber particles and matrix, further extension of cracks caused damage to the adjacent nano-SiO2 particle and matrix interface.nano-SiO2 particles increased the stiffness of alloy and the strength and toughness of the alloy. Mesoscopic simulation revealed the elastic-plastic mechanical behavior of ABS/PMMA with ABS/PMMA/nano-SiO2 blend/rubber particles and nano-SiO2 particles. The failure process and the effect of simulation research have important theoretical significance and engineer... |
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