Study on Toughening of Core-Shell Copolymer

A polymer synthesized by core-shell emulsion copolymerization technology. The seed latex is prepared by first using one or several monomer mixtures, and then one or several monomers are added to polymerize on the seed to obtain a polymer with a combination of hard core soft shell or soft core hard shell. Since there is a graft copolymer between the core and the shell, the compatibility of the two incompatible polymers can be improved. The core-shell polymerization technology can be used for polymer design as required, and monomers with different properties can be made into heterogeneous polymers with different compositions and shapes, and products with different functions and properties can be made.

The main role of core-shell particle toughening engineering plastics is the rubber core, so the main explanation is the rubber toughening mechanism. The craze-shear band theory can reasonably explain the toughening of engineering plastics with core-shell particles. The impact strength has a single growth relationship with the particle size of the modifier particles. To suppress the growth of craze, the size of the core-shell particles of the modifier must be consistent with the size of the craze. Therefore, the impact modification of PP or PS with crazing fracture requires the use of core-shell particles with a larger particle size to effectively terminate the crazing. For PVC with shear band fracture, core-shell particles with a smaller particle size are used to increase the number of modified particles per unit weight or unit volume, so that the effective volume fraction of core-shell particles in the polymer formulation increases, and the ability of the location to intercept and disperse stress. Therefore, toughened PVC should use small-sized core-shell particles.

Core-shell particles MBS are used in the blending modification of PC. They can be well dispersed in the PC matrix and have good interface adhesion. While the processing performance of PC is improved, its toughness can be greatly improved. Impact strength, PC also has improved low temperature toughness and high temperature stability.