Preparation Of Silicon Ester Hyper Dispersants And Its Application In CaCO₃/PE Composite Materials

The plastic filled by modified superfine powder was a hot spot in the develop of plastics industry. First, it can reduce the cost; second, it can improve the properties of plastic composites. And the effect of powders modification has become a major problem in the field of modified plastic. At present.There are massive scientific researchs at home and abroad in this field. Especially, hyper dispersants as a new type of effective dispersant agent have been well-known. The research aimed at current modified plastics field,based on the specific inorganic powder and organic resin, we designed and synthesized a new type hyper dispersants. At the same time, used the self-made hyper-dispersants modified inorganic particles, and prepared the organic resin composite materials filled by modified inorganic particles through melt blending and injection molding.At the same time,we also studied the mechanical properties, melt index, crystal properties and other properties of composite materials.(1) Based on the molecular structure design theories, taking the surface properties of superfine particles of CaCO3 and CaSO4 and the basic properies of PE resin as reference data, and combined the solid surface adsorption of coupling agent and the long enough polymeric chains of hyper dispersants which providing steric stabilization barrier around the pigment particle, a new type of silicon ester polyester hyper dispersant was designed and synthesized. In view of the small polarity of PE resin, 12-hydroxy stearic acid with the same small polarity was selected as the monomer and it was also used as the major component of Solsperse series hyper dispersant of the British company ICI. Used stannous octoate as initiator, II toluene as solvent, and under the protection of the antioxidant, the poly 12-hydroxy stearic acid was synthesized through solution polycondensation approach. Used the ethyl petrol silicate transesterificated with poly 12-hydroxy stearic acid after Capping it by isooctanol, and then the new type hyper dispersants was synthesized. In order to verify the feasibility of the transesterification method, we continued to use ethyl petrol silicate transesterificated with low molecular weight alcohol, and collected the colorless and transparent by-product which had a strong odor of alcohol. Through gas chromatography test, the by-product was validated for ethanol. Such a design method which based on the nature of special superfine particles and organic esin and synthetic method for the new type hyper dispersants has not been reported.(2) Based on dry modification method, successfully coated the 1250 mesh ground CaCO3 and CaSO4 and talc inorganic powders used the self-made hyper-dispersant agent, and found the organic groups on the modified powder surface through FT-IR were tested for modified powders. Compared with the rotation viscosity, volume of the settlement of modificated inorganic powders in liquid paraffin, selected the silicon ester hyper dispersants as the best one for modifying ground Calcium Carbonate and used the modified calcium carbonate as the filler of PE resin. Based on different molecular weight of solvent chain (MB) and different modified systems, the performances of modified CaCO3/PE composites were studied. The results show that on the premise of maintaining tensile strength and flexural strength, it could improve the toughness of composites,Compared with the unmodified system, the Impact strength increased by 50%.And compared with stearic acid singly, the melt flow index of its compound with polyester hyper dispersants (MB=1830) was over three times higher.(3) Used the ethyl petrol silicate transesterificated with low molecular weight alcohol, including isooctanol, dodecanol and octadecanol.The rotation viscosity and volume of the settlement in liquid paraffin were tested for the best Synthetic condition. The feasibility of the test scheme is proved by gas chromatograph test. Put the heavy calcium carbonate (1250 mesh) unmodified, the calcium carbonate modified by self-made dispersants and modified by F2 into torque rheometer, and melt blending with PE (6070). Simultaneously, recorded the torque curve of master batch (CaCO3 content is 80%). Finally, prepared the master batch with PE (TR490) for injection molding, and the composites mechanical properties and crystallization behavior were tested. The results show that the mechanical properties of CaCO3/PE composites modified were better than the unmodified. Compared with F-2 singly, the mechanical properties of CaCO3/PE composites modified by silicon ester dispersants with different molecular weight was better.