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Study On Preparation And Properties Of Thermoplastic Resin/Montmorillonite Nanocomposites

Posted on:2004-12-29Degree:MasterType:Thesis
Country:ChinaCandidate:G D LiangFull Text:PDF
GTID:2121360092992894Subject:Materials science
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In the thesis, organic-montmorillonite(Org-MMT) was obtained by an ion-exchange reaction between Ca-montmorillonite(Ca-MMT) and alkylammonium ion, leading to increase the basal spacing of montmorillonite. X-ray diffraction (XRD) analysis indicated that alkylammonium ions had already exchanged with Ca+ ions in Ca-montmorillonite. Nanocomposites based on polymer and Org-MMT was prepared by melt intercalation, structure and crystallization behavior of nanocomposites were investigated. Two parts were included in this thesis.1. Polypropylene (PP)/PP-g-MAH/Org-MMT nanocomposites were prepared by melt intercalation. XRD, transmission electron micrograph (TEM) and polarized optical micrograph(POM) were used to measure the structure of nanocomposites, the nonisothermal crystallization kinetics of PP/PP-g-MAH/Org-MMT was studied by differential scanning calorimetry (DSC), and their mechanical properties were tested. It was found that:(1) XRD and TEM analysis showed that polymer molecules could intercalate into the interlayer of Org-MMT, leading to the formation of PP/PP-g-MAH/Org-MMT intercalation nanocomposites.(2) The value of tensile strength of PP/PP-g-MAH/Org-MMT nanocomposite was much higher than that of pure PP at the load of 2wt% Org-MMT and 10wt% PP-g-MAH. However, the value of izod impact strength of PP/PP-g-MAH/Org-MMT is close to that of virgin PP.(3) POM analysis showed that spherulitic structure of pure PP is remarkable. Compared with the spherulites of virgin PP, those of PP/PP-g-MAH/Org-MMT nanocomposites with less size were observed. XRD analysis showed that the crystallite size of nanocomposites perpendicular to the crystalline plane like (040), (130),(111),(041) obtained the minimum value when the content of PP-g-MAH is 20 wt%.(4) The nonisothermal crystallization kinetics of PP/PP-g-MAH/Org-MMT was investigated by differential scanning calorimetry with various cooling rates. The Jeziorny and a method developed by Mo could be imployed to describe the nonisothermal crystallization process of PP/PP-g-MAH/Org-MMT nanocomposites very well. The difference of Avrami factor n betweennanocomposites and PP indicated that the nonisothermal crystallization of nanocompostie corresponded to a tridimensional growth with heterogeneous nucleation. The value of F(T) of nancomposites was larger than that of PP, indicating that the crystallization rate of nanocomposite was faster than that of PP. 2. Polyethylene(PE)/PE-g-MAH/Org-MMT nanocomposites were prepared by melt intercalation. XRD, and transmission electron micrograph (TEM) were used to measure the structure of nanocomposites, the nonisothermal crystallization kinetics of PP/PP-g-MAH/Org-MMT was studied by differential scanning calorimetry (DSC), and their mechanical properties were tested. It was found that:(1) XRD and TEM analysis showed that polymer molecules could insert into Org-MMT having been treated by octodecimoalkyl ammonium chloride, and interlayers of Org-MMT were dispersed in HOPE evenly, leading to the formation of HDPE/PE-g-MAH/Org-MMT nanocomposite.(2) XRD analysis showed that better intercalation effect could be obtained by adopting ammonium ion with longer molecule length, solvent method and high density polyethylene.(3) The nonisothermal crystallization kinetics of HDPE/PE-g-MAH/Org-MMT was investigated by differential scanning calorimetry with various cooling rates. The Jeziorny and a method developed by Mo could be employed to describe the nonisothermal crystallization process of PE/PE-g-MAH/Org-MMT nanocomposites very well. The difference of Avrami factor n between nanocomposites and HDPE indicated that the nonisothermal crystallization of nanocompostie corresponds to a tridimensional growth with heterogeneous nucleation. The value of F(T) of nancomposites was larger than that of HOPE, indicating that the crystallization rate of nanocomposite was faste...
Keywords/Search Tags:Montmorillonite, Nanocomposite, Melt intercalation, Polypropylene, Polyethylene, Nonisothermal crystallization kinetics, Spherulites, Crosslinking, Gel.
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