In this paper, slow pelleting flocculation of polymer latex consisting of butadiene, styrene and methyl methacrylate(MBS) were investigated, using aqueous H2SO4 as coagulant. It is found that spherical particles with ...In this paper, slow pelleting flocculation of polymer latex consisting of butadiene, styrene and methyl methacrylate(MBS) were investigated, using aqueous H2SO4 as coagulant. It is found that spherical particles with uniform particle size and high bulk density were produced in the narrow range of pH. In order to obtain good particle morphology, well-distributed concentration, temperature and shear field in the coagulating system were required. Polymer latex made from emulsion polymerization often needs to be converted into dry powders. Usually, we simply add excessive coagulant, such as inorganic acid, salt, etc., into latex emulsion to make it coagulate. The particles formed with such method always have irregular shape and high fines content. In recent years, more attention has been paid to the method of getting coagulated particles with satisfactory particle morphology(1-3)].展开更多
Special microspheres dispersed in epoxy resin prior to curing can toughen brittle resin by formation of a second phase. In this work, rigid particles (HP), hollow particles (PO) and rubber powders (PR) are used to mod...Special microspheres dispersed in epoxy resin prior to curing can toughen brittle resin by formation of a second phase. In this work, rigid particles (HP), hollow particles (PO) and rubber powders (PR) are used to modify epoxy resins for the study on the toughening mechanism. The single-edge notched three-point bending test and T peel test have been used to measure the toughness of epoxy resin. The morphology (particle/matrix interfacial shape) of epoxy resin modified with these three kinds of microspheres has been investigated by transmission electron microscopy (TEM). The results show that these three kinds of modifiers are all effective, and the core-shell rubber particle (PR) is the best toughening modifier among them. It is also found that the toughening effect is dependent on the morphology of the interface between the particles and matrix and the different curing conditions really result in obviously different interface states. The excellent interfacial interaction plays a significant role in toughening epoxy resin.展开更多
文摘In this paper, slow pelleting flocculation of polymer latex consisting of butadiene, styrene and methyl methacrylate(MBS) were investigated, using aqueous H2SO4 as coagulant. It is found that spherical particles with uniform particle size and high bulk density were produced in the narrow range of pH. In order to obtain good particle morphology, well-distributed concentration, temperature and shear field in the coagulating system were required. Polymer latex made from emulsion polymerization often needs to be converted into dry powders. Usually, we simply add excessive coagulant, such as inorganic acid, salt, etc., into latex emulsion to make it coagulate. The particles formed with such method always have irregular shape and high fines content. In recent years, more attention has been paid to the method of getting coagulated particles with satisfactory particle morphology(1-3)].
文摘Special microspheres dispersed in epoxy resin prior to curing can toughen brittle resin by formation of a second phase. In this work, rigid particles (HP), hollow particles (PO) and rubber powders (PR) are used to modify epoxy resins for the study on the toughening mechanism. The single-edge notched three-point bending test and T peel test have been used to measure the toughness of epoxy resin. The morphology (particle/matrix interfacial shape) of epoxy resin modified with these three kinds of microspheres has been investigated by transmission electron microscopy (TEM). The results show that these three kinds of modifiers are all effective, and the core-shell rubber particle (PR) is the best toughening modifier among them. It is also found that the toughening effect is dependent on the morphology of the interface between the particles and matrix and the different curing conditions really result in obviously different interface states. The excellent interfacial interaction plays a significant role in toughening epoxy resin.
