کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
9559766 1381246 2005 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Montmorillonite intercalated by ammonium of octaaminopropyl polyhedral oligomeric silsesquioxane and its nanocomposites with epoxy resin
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Montmorillonite intercalated by ammonium of octaaminopropyl polyhedral oligomeric silsesquioxane and its nanocomposites with epoxy resin
چکیده انگلیسی
The octaammonium chloride salt of octaaminopropyl polyhedral oligomeric silsesquioxane (OapPOSS) was synthesized via the hydrolytic condensation of γ-aminopropyltrimethoxysilane in the methanol solution catalyzed by concentrated hydrochloric acid and was further used as the intercalating agent to modify sodium montmorillonite (MMT). X-ray diffraction (XRD) data indicate that the MMT was successfully intercalated by the ammonium of OapPOSS, as evidenced by the fact that the basal spacing of MMT galleries was expanded from 1.3 to 1.7 nm. The intercalation method used here introduced only the octaammonium POSS salt in contrast to the introduction of all hydrolyzed products from γ-aminopropyltriethoxysilane (APTEOS). The POSS-modified MMT was exploited to prepare the epoxy-MMT nanocomposites. Using a two-step technique, the disorderly exfoliated epoxy-MMT nanocomposites were obtained. XRD studies showed that the formation of the nanocomposites in all the cases with the disappearance of the peaks corresponding to the basal spacing of MMT. Transmission electronic microscopy (TEM) was used to investigate the morphology of the nanocomposites and indicates that the nanocomposites are comprised of a random dispersion of intercalated/exfoliated aggregates throughout the matrix. Differential scanning calorimetry (DSC) indicates that the glass transition temperatures of the as-prepared epoxy-MMT nanocomposites remained invariant in comparison with that of the control epoxy when the POSS-MMT content is less than 10 wt%. However, the nanocomposite containing 15 wt% of POSS-MMT displayed a decreased Tg, which could be attributed to the incomplete curing reaction resulting from the POSS-MMT loading. Thermogravimetric analysis (TGA) shows that the incorporation of POSS-MMT into epoxy networks displayed an apparent improvement in the thermal stability, and the char residue increased with increasing the concentration of POSS-MMT.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 46, Issue 1, 6 January 2005, Pages 157-165
نویسندگان
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