Study On Polyurethane Elastic Particles Toughness Polystyrene

The elastic particle toughened polystyrene(PS)can easily cause the decrease of the strength of the blend,improving the toughness of the PS and ensuring its comprehensive performance,which has both practical significance and academic significance.In this paper,two different modification methods are provided for this problem.The effects of homogeneous and multiphase elastic particles on the mechanical properties and fracture mechanism of the blends are studied.High-modulus,high-strength compounded urethane rubber(MPU)was used to toughen the toughened polystyrene through a dynamic vulcanization process.The dynamic vulcanization process and the effect of phase morphology and structure of the homogeneous rubber on its mechanical properties and impact of the fracture mechanism were studied.The results show that the effect of MPU on the performance of PS is related to the rubber fraction.When the rubber mass fraction is less than 20%,the tensile strength does not change much,the impact performance increases by an average of 1.3 times,and when the mass fraction of rubber exceeds 25%,the impact strength increases by an average of 3.5 times,the elongation at break increased by an average of 2.9 times,and the tensile strength decreased by an average of 44.3%.With the analysis of phase morphology and structure,when the rubber phase is "island" phase and has a certain modulus,good comprehensive performance can be obtained.In order to further improving its comprehensive performance,polysynthetic polyurethane elastic particles of PS-PU soft shell hard core are used to toughen and reinforce polystyrene.The characterization of core-shell polymers shows that core-shell particles satisfying processing conditions with different core-shell ratios and better thermal stability have been successfully synthesized.The effects of different core-shell ratios and additions on the mechanical properties of polystyrene were studied.The results show that the material will undergo brittle-ductile transition when modified by multi-phase elastic particles.When the ratio of core to shell is 1.5:1,the brittle-ductile transition point is 3%.The maximum impact strength is 3.32 times higher than that of pure polystyrene,the average tensile strength increased by 8%.Hard-shell toughening and toughening modification depends on the thickness of the flexible layer.Only the flexible layer with appropriate thickness will cause shearing and yielding of the matrix during the failure process to increase the toughness,and at the same time,it can be reinforced due to the presence of hard cores.