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Study On Novel Polymeric Nanocomposite

Posted on:2002-12-04Degree:MasterType:Thesis
Country:ChinaCandidate:M L GeFull Text:PDF
GTID:2121360032956371Subject:Materials science
Abstract/Summary:PDF Full Text Request
In recent years, polymer-clay nanocomposites have attracted great interests from researchers since they frequently exhibit unexpected hybrid properties synergistically derived from the two components. In most cases, the new and improved properties are derived when the dimensions of dispersion clay is less than I OOnm and many techniques have been attempted for the ultrafine dispersion of clay into the polymer matrix. This is due, in great part, to the recent developments of new ftinctionalization of smectic clays, especially Na~-montmorillonite(Na-Mont). .ln this article, Organic-Montmorillorite (Org-Mont) was prepared by ion-exchange from Na type montmorillorite (Na-Mont), leading to increase the basal spacing of montmorillonite. Polypropylene/Organo-montmori llonite (PP/Org-Mont) Polyoxymethylene/montmori llonite (POM/Mont) and Poly (vinyl Chloride)/organo- montmori I lonite(PVC/Org-Mont) nanocomposites were prepared by melt intercalation. At the same time, their structures were measured with Fourier transform infrared (FTIR) and X-ray diffraction (XRD). Their mechanical properties were tested. The results from X-ray diffraction showed that the molecular chains of PP had intercalated into the gallery of Org-Mont through melt intercalation, POM macromolecules can be inserted into Org-Mont or Na-Mont layers, PVC melt could not be intercalated into Na-Mont layers, but could be intercalated into layers of Org-Mont. The composites of PVC/Org-Mont were exfoliated nanocomposites. The nonisothermal crystallization kinetics of nanocomposites is studied by means of differential scanning calorimetry (DSC) and compared with those of PP and POM. The modified theory of Avrami by ieziorny~ Ozawa and Mo methods were used to analyze the data of DSC. The result shows that both Jeziorny and Mo methods could describe this system very well, but Ozawa analysis failed. The addition of organic montmorillonite decreased the activation energy of crystallization of the polymer, which was used as nucleating agent during nonisothermal crystallization process of polymer. The crystallization temperature of the composites was higher than that of the original polymer. The addition of Org-Mont increased the size of crystallization of the polymer, but the addition of Na-Mont decreased the size of crystallization of the polymer. The glass transition temperatures of PVC/Org-Mont nanocomposites were studied with DSC. The glass transition temperatures of PVC/Org-Mont nanocomposites were lower than that of neat PVC. Mechanical property testing indicated that the PVC! Org-Mont nanocomposites were better than PVC/Na-Mont composites. However, the tensile strength, izod type notched impact strength and charpy type notched impact strength of PVC/organo-mont nanocomposites were fitted with the linear expressions: t =722.41 -8.93Tg, NI 1574.92-7.25Tg and NCI=4 I 7.43-5.5OTg, respectively.
Keywords/Search Tags:Montmorillonite, Nanocomposite, Melt intercalation, Polypropylene, Polyoxymethylene, Poly (vinyl Chloride), The nonisotherrnal crystallization kinetics, The glass transition temperatures
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