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The Intercalation Self-Assembly Of Polyhedral Oligomeric Silsesquioxane-Montmorillonite And Study On PS Composite

Posted on:2008-08-08Degree:MasterType:Thesis
Country:ChinaCandidate:Y ShenFull Text:PDF
GTID:2121360215980892Subject:Materials science
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Octaammonium chloride salt of octaaminopropyl polyhedraloligomeric silsesquioxane(oapPOSS) was synthesized by the hydrolyticcondensation ofγ-aminopropyltrithoxysilane in the methanol solutioncatalyzed by concentrated hydrochloric acid. The product was deposited bytetrahydrofuran. The prepared compounds were characterized by FTIR, 1HNMR, 9Si NMR, 13 C NMR, DSC. The effect of temperature, reaction time,amount of hydrochloric acid, amount of THF on the yield of product weredetailed in this paper. The optimal reactive conditions were obtained asfollows: the volume ofγ-aminopropyltrithoxysilane was 15 mL,methanol was 360 mL, hydrochloric acid was 15 mL, tetrahydrofuran was 250 mL, reaction at 90℃for 18h. The results of DSC analysis show themelt point was 412.65℃.The oapPOSS had good thermal property. Thecrystal structure of oapPOSS was determined by Wide-Angle X-rayDiffraction (WAXD). Its diffraction line was indexed by Ito method. Theindexing result showed that the crystal was the orthorhombic system withsimple lattice. All the cell parameters of oapPOSS were listed as below: a=38.1554, b= 3.998771, c= 3.855281, a=β=γ=90°.Na-montmorillonite was modified by Octaammonium chloride salt ofoctaaminopropyl polyhedral oligomeric silsesquioxane(oapPOSS).Theintercalation reagent has intercalated into the galleries of montmorilloniteas detemined by FTIR,TGA,XRD. The result showed that the blend ofoapPOSS not only could increase the interlamellar space of themontmorillonite from 1.3nm to 1.7nm, but also could overcome thedrawback of weak thermals tability of conventional intercalating agents.Polystyrene/MMT(PS/MMT) nanocomposites were prepared throughbulk free radical polymerization by oapPOSS modified MMT in styrenemonomer. The structure and physical properties were studied by FTIR,XRD, DSC, TGA and GPC. The results indicated that compared with purePS and unmodified MMT/PS, the nanocomposites prepared by oapPOSSmodified MMT and styrene monomer possessed better thermal property.The nanocomposite displayed much higher glass transition temperatures(Tg)and thermal decomposition temperature.
Keywords/Search Tags:polyhedral oligomeric silsesquioxane (POSS), octaammonium chloride salt of octaaminopropyl polyhedral oligomeric silsesquioxane, synthesis, montmorillonite, modification, polystyrene, nanocomposites, thermal property
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