| Montmorillonite is a typical layered silicate mineral, which is widely used due to its cation exchange, water absorption and good dispersion proprties. But the montmorillonite has bad dispersibility in poly-system materials originated to its strong surface polarity, so it is necessary to have an organic modification for its further application. In this experiment, we synthesis a novel organic montmorillonite and study its application in PP. In addtion, we also investigated Na-montmorillonite which is applied in WPU due to its good water-aborbility. In a word, the influence of the montmorillonite content to polymer based nanocomposites in their composition, structure and peformance is investigated in detail.In the second chapter, a novel organic montmorillonite was prepared by four step of modified Na-montmorillonite. The first insert montmorillontie (MMT-C) was prepared by cation exchange with cetyl trimethyl ammonium bromide. On the basis of MMT-C, the second step of Hydroxyl-terminated montmorillonite (MMT-E) was prepared by the grinding method with epoxy resin ring opening of diethanolamine. Using the isophorone diisocyanate (IPDI), synthesis the third step of NCO-terminated montmorillonite (MMT-I). At last, the final alkyl chain-terminated montmorillonite (MMT-O) was prepared by intercalation modification with octadecylamine (ODI). FTIR, XRD, TG, BET and TEM were applied to study the structure of the organic montmorillonite (MMT-O). The results showed that organic reagents had intercalated into the layers of Na-MMT, the space of the montmorillonite layers have increased from1.5626nm up to4.2828nm.In the third chapter, the PP/MMT-O nanocomposites were synthesized through melt intercalation in twin-screw extruder. We prepared a series of nanocomposites by changing the content of MMT-O. The observation with TEM and SEM revealed that MMT-O was evenly dispersed to nanometer scale and dispersed in PP matrix in the form of intercalation, only a little was in the form of exfoliated structure. The increase of MMT content enhances the thermal stability of PP/MMT-O nanoconposite materials. With the addition of MMT-O, thermal properties of the nanocomposite could be greatly improved. The results show that the tensile strength, the percentage of breaking-elongation and the impact strength of PP/MMT-O nanocomposites reached to maximum when MMT-O content was5%. It had been also found that the crystallinity of PP was increased, but the melting point of PP changed little with increasing of MMT-O content in nanocomposites, the dimension of the spherulite reduced and the shape became distorted. In the fourth chapter, a novel WPU/MMT-Na (WPUM) composite was prepared successfully by incorporating Na-montmorillonite aqueous solution into polyurethane prepolymer(WPU) which was synthesized using polyether glycol(N210) and isophorone diisocyanate (IPDI) as the main materials. Comparing with nanocomposites before modification, the distribution and interlamellar space of MMT-Na in WPU was analyzed and effects of MMT-Na amount on structure and properties of WPU were discussed. From the SEM and TEM analyses, it was found that the MMT-Na layers dispersed uniformly in the WPUM matrix. But with increasing the amount of MMT-Na, MMT-Na appeared agglomeration and bad dispersity in the composite emulsion. XRD results illustrated that emulsion blend had an obvious effect on increase in the interlayer spacing of MMT-Na which had increased from1.28nm up to1.53nm. In addition, the incorporation of MMT-Na was also capable of enhancing the thermal resistance and mechanical property. With increased loading of MMT-Na, the particle size and conductivity of composite emulsion showed a gradual increase in the trend. |
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