shandong Repolyfine chemical co.,ltd

MBS additives are commonly known as MBS resins. As one of the most important impact modifiers of PVC, MBS resin can not only maintain the transparency of PVC to the greatest extent while toughening, but also greatly improve the toughness of the product compared with other impact modifiers with the same amount of addition, so it is widely used in the processing and application of engineering plastics such as PVC and PBT/PC.
The cause of material failure under stress of glassy materials (such as PVC resin) is the forced high-elastic deformation of the material. If there are structural defects such as impurities, fillers, voids, bubbles and other defects in the deformation part, the stress is easy to concentrate in the weak part, so that the rupture develops rapidly, resulting in the material being destroyed when it is much lower than the theoretical average strength. Pure PVC resin is a brittle material, and the continuous glass phase cannot prevent the sharp expansion of cracks under the action of stress, and finally form gaps and cracks to rupture, so the impact resistance is poor. To improve the impact resistance of brittle materials, rubber toughening is widely used. Since the 50s, people have begun to study the rubber toughening mechanism of materials, and have put forward a variety of different theories, such as the direct absorption theory of energy, the yield expansion theory, the crack core theory, the silver-shear belt theory and the silver-vein branching theory, etc., and continue to develop and improve, and gradually establish a preliminary theoretical system of rubber toughening mechanism. Two important conclusions are drawn from the above theory: first, the impact strength of the toughened material is exponentially related to the number of rubber particles in the system; The second is to make the rubber particles effectively branched silver, and its diameter shall not be less than the thickness of the silvergrain, otherwise it will be buried in the silvergrain and will not work.
MBS resin is a functional polymer material synthesized on the basis of particle design concept, which is a ternary polymer prepared by emulsion grafting polymerization, with a typical core-shell structure in submicroscopic morphology, and the core of the particle is a styrene-butadiene rubber core with low shear amount after light cross-linking, which mainly plays a role in improving the impact toughness of the polymer. The shell is a hard shell formed by the grafting of styrene and methyl methacrylate, and the main function of MMA in the shell is to improve its compatibility with PVC, so that MBS can be evenly dispersed in the PVC body. ST is mainly to improve the refractive index of MBS resin to make MBS have a refractive index similar to that of PVC, so MBS resin is a typical particle dispersion toughening modifier. It is semi-compatible with PVC and PVC, that is, it has good interfacial compatibility with PVC resin, and keeps the particle shape intact in PVC/MBS system. When the amount of MBS is small, it has good dispersion in PVC and is a spherical particle, which cannot form a dispersed "sea-island" structure, and cannot play the role of transmitting impact energy, and the toughening effect of the material is not good. As the amount of MBS resin increases, the dispersed particles gradually coalesce to form an island structure. When the material is impacted by external force, the rubber core in the MBS resin is the stress concentration point, which causes it to deform, and induces silver veins and shear bands around it, through which the impact energy is dispersed and absorbed, forming the transformation of the material from brittle fracture to ductile fracture, so as to achieve the purpose of toughening