Synthesis And Characterization Of Polymer/Intercalation Modified Kaolin Composite Materials

Kaolin is a typical layered silicate mineral, the layer spacing is 0.72nm.But the kaolin has bad dispersibility in polymer materials originated to its strong surface polarity, so it is necessary to have modification for its further application. In this experiment we were prepared intercalation modified kaolin and explored its intercalation conditions. In addition, we also investigated intercalation modified kaolin which was applied in polyurethane emulsion, polypropylene, ABS matrix and the effect of the amount of modified kaolin intercalation of polymer matrix composites structure and properties.In the second chapter, (1) Kaolin intercalation process were discussed:a mass ratio of DMSO、kaolin and methanol(water) 1:1:10,65℃ ultrasonic agitation after 3h (ultrasonic temperature was 60 ℃), and then 80 ℃ low speed stirring 4h. XRD results show that the d001 of kaolin was enlarged from 0.72 to 1.11nm, the intercalation rate was 67.3%, while the infrared spectrum displayed DMSO successfully inserted into the inter-layer of kaolin; (2)Based upon X-ray diffraction, the factors that influence the kaolin/Potassium acetate intercalation were investigated. The results show that the intercalation of kaolin by Potassium acetate is greatly related to concentration of intercalating agent. With increasing concentration of potassium acetate the intercalation rate showed an increasing trend:when using dry milling intercalation the rate of intercalation was 34.4%; The higher concentration of intercalating agent such as saturated potassium acetate and potassium acetate natural moisture can get higher rates of intercalation were 45.7% and 76.3%; (3) Appropriate to extend the intercalation reaction time can get a higher rate of intercalation.In the third chapter a novel intercalated waterborne polyurethane/kaolin composites were prepared by in-situ intercalated polymerization method with the kaolin/DMSO intercalation composite. The structure of composite was characterized by XRD, TEM, SEM and TG. The results show that DMSO was inserted into the inner layer of kaolin and the lamellar spacing of kaolin was expanded from 0.72nm to 1.11nm. Most of the kaolin were intercalated or exfoliated in waterborne polyurethane matrix when the content of intercalated kaolin was lower than 1.6%. Compare with the pure polyurethane, thermal stability of the composites was improved, the maximum thermal weightlessness of hard segment increases by 50 ℃. When the content of the intercalated kaolin was 1.6%, the mechanical properties of the composites was the best, the tensile strength and elongation at break were increased by 35% and 10%.In the forth chapter, the kaolin was intercalated by potassium acetate.Used the ball mill to sheathe surface of modified kaolin with ODA to prepare hydrophobic intercalary modified kaolin and got the PP/modified kaolin composite materials by melt blending with PP. The structure of the modified kaolin was characterized by FTIR and XRD. The morphology, mechanical properties and heat resistance of composite material have been observed through transmission electron microscopy (TEM), scanning electron microscope (SEM), tensile tests and thermogravimetry (TG).The results indicated that, the intercalated kaolin layer spacing was1.42nm, the layer spacing was increased 0.7nm and intercalating rate reached 79.7%. The modified kaolin lamella was uniformly dispersed in PP matrix, with increasing the mass fraction of modified kaolin, the mechanical properties and thermal stability of the materials were improved obviously. When the mass fraction of modified kaolin was 7%, the tensile strength of the composites increasing 34.22% and the elongation at break increasing 29.3%.The potassium acetate was used for intercalating modified kaolin and the conditions were also studied:the best modified technology were 1:2 of the mass ratio between potassium acetate and kaolin, Dried and ground for about one hour at 50 ℃ until moisture into paste and then seal placed 24h.XRD results showed that not intercalated kaolin layer spacing is 0.72nm, intercalated kaolin layer spacing was1.42nm, intercalating rate reached 79.7%.Used the ball mill to sheathe surface of modified kaolin with KH570 hydrolyzate to prepare hydrophobic intercalary modified kaolin and got the ABS/modified kaolin composite materials by melt blending with ABS. SEM、TG study microstructure of composite material, and mechanical properties of composite materials was studied. The results showed that modified kaolin lamella were uniformly dispersed in ABS matrix. When the mass fraction of modified kaolin was 7%, the elongation at break tensile strength of the composites film was obviously higher than pure ABS. Furthermore, the thermal stability was improved.