Study On The Toughening Of ABS By Modified Calcium Carbonate And Pressure Induced Flow Processing

The nanocomposites of ABS with modified calcium carbonate nanoparticles were preparedby pressure-induced flow (PIF) processing. Through modification, the toughness of the resin hasbeen greatly improved. We systematically studied the relationship of material’s microstructureevolution and material toughness, qualitatively explained the role of nano calcium carbonate intoughening the resin. On this basis, we proposed a new model of toughening plastic with both"soft" and "hard" domains.According to the research on mechanical properties, we found that adding nano calciumcarbonate particles into ABS resin but without PIF processing, the toughness of resin droppedslightly. However, after PIF processing, the toughness was increased significantly. When thecontent of nanometer calcium carbonate was10wt%and the compression ratio was1.9, theimpact strength was increased by331%, the elongation at break was0.6, and the tensile toughnesswas increased up to1335%. For comparison, ABS with same PIF compression ratio, but withoutintroduction of nanometer calcium carbonate, the impact strength was increase by66%and thetensile toughness was increased up to582%. Therefore, we suggested that PIF processing andintroduced nanometer calcium carbonate particles introduced a new way of microcrack formationand propagation, so as to absorb more energy during fracture.We characterized microstructure of samples by combination of TEM and SAXS, and foundthat with the increasing compression ratio of ABS, spherical rubber domains transferred intooriented disks and stacked perpendicular to the direction of stress. The disk shape rubbery nanodomains could effectively terminate the growth of cracks, so as to improve the toughness of ABS.SEM results showed that after PIF processing, the surface roughness of samples increasedsignificantly, and nano calcium carbonate particle can be peeled-off from the resin. Rigid particlesthat caused a large number of holes was another reason for toughening. For nanocomposites without PIF processing, the rubbery domains could not hinder the extension of micro cracksinitiated by cavitation. Consequently, solely adding the nanometer calcium carbonate, thetoughness of the material was slightly reduced.Based on the research results, we draw the following conclusion, rigid particles couldintroduce more micro cracks, and soft disk rubbery particles could effectively terminate the microcracks propagation, the toughness increased significantly by the synergetic effects.