Study On Preparation Of Submicron,Nano-particles And Its Application In Polymers(Ⅰ)

This study is to develop some filling materials (composite nano-CaCO3 and submicron zinc borate ZB2335 fire retardant) and their applications in polymer.With CaCl₂, ZnCl₂, water glass(WG) and polymer P as the raw materials, nano-particles(nano-CaCO₃ with square-like and rod-like shapes, and nano- CaCO₃ / zinc silicate with rod-like shapes---all of them were coated with amorphous SiO₂.) were prepared by coprecipitation. The effects of the operating conditions on the shape and the size of composite nano-CaCO3 were investigated. The shape, the size and structure of composite nano-CaCO₃ were characterized by TEM, WXRD (wide-angle XRD) and FTIR, respectively. The results revealed that many factors affected the shape and the size of the composite nano-CaCO₃ particles greatly, such as the concentrations of WG and polymer P, the pH values of reaction system, the concentration ratio of Ca²⁺ and Zn²⁺, and the aging time as well. Square-like nano-CaCO3 particles contains both calcite and aragonite, rod-like nano-CaCO₃ contain calcite, rod-like nano-CaCO₃/zinc silicate indexed into orthorhombic system, which were obtained under the optimum reaction conditions. All of these nano-particles can be modified easily due to SiO₂ coating on the surface of nano-CaCO₃ particles.With ZnO and H₃BO₃ as the raw materials, dispersant U, dispersant S, dispersant C, dispersant H, polymer P, and polymer K as dispersants respectively, the samples submicron zinc borate (ZB2335) particles were prepared through two pass-reaction. The effects of the operating conditions on the shape and size of the ZB2335 particles were investigated. The structure, shape and size of the ZB2335 particles were characterized by WXRD, FTIR, TGA, Zeta electric potential analysis, and Lasergrainsize analysis, respectively. The results revealed that the concentration ratio of ZnO and H₃BO₃, the species of dispersants, the size of ZnO particles, the feeding mode, the reaction temperature, the pH value and the reaction time affected the structure, the shape and size of ZB2335 particles greatly. A size of 200—500 nm, pyramid-like ZB2335 particles with good dispersibility were obtained under the optimum reaction conditions.With organic acid and YDH-750(silane coupling agent), TMC-301(titanate coupling agent), and TMC-211(titanate coupling agent) as modifying agents respectively, both composite nano-CaCO₃ and submicron ZB2335 particles were modified. The effects of the operating conditions on the properties of modified of composite nano-CaCO₃ and submicron ZB2335 particles were investigated with the help of FTIR and the falling method in organic solvent. The results showed that the quantity of modifying agent affected the properties of particles greatly. After modified the compatibility with organic solvent became better for zinc borate samples. The polarity of the SiO₂-coated nano-CaCO₃ was also better while modified by TMC-301. And the nonpolarity of composite of nano-CaCO₃/zinc silicate became stronger after modified by maixed organic acid and YDH-750.The influence of SiO₂-coated nano-CaCO₃ particles as filler on polypropylene (PP) was studied. The results showed that the bending strength and thermal stability of PP can increase evidently, while the viscosity of PP was decreased when adding all kinds of nano-compound particles. Furthermore, the bending modulus and bending strength of PP were increased to some degree when using only amorphous SiO₂ coated nano-CaCO₃; The breaking strength of PP was increased to some degree, and the impact strength, bending modulus were decreased a little when modified by TMC-301. The toughenss and the strength of PP were increased markedly and the property parameters were improved when using composite nano-CaCO₃/zinc silicate as filler, which were modified by mixed organic acid and YDH-750.