کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1398508 | 984392 | 2007 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Novel propylmethacrylate-monofunctionalized polyhedral oligomeric silsesquioxanes homopolymers prepared via radical bulk free polymerization
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
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چکیده انگلیسی
Novel propylmethacrylate-monofunctionalized polyhedral oligomeric silsesquioxanes (POSS-PMA) homopolymers were obtained, in good yield, by free bulk radical polymerizations of the low melting macromer heptaisobutylpentacyclooctasiloxan-1-(yl)propylmethacrylate [(PMA)(i-Bu)7T8], 1, by using different initiator/macromer molar ratios. Their characterization was accomplished by TG, DTG and DSC analyses, Gel permeation chromatography (GPC) and MALDI-TOF mass spectrometry. The results indicate that both macromolecular as well as the thermal properties of the new materials are dependent on the initiator/macromer molar ratio used in the polymerization process. By increasing the amount of initiator, polymers with lowest molecular masses, highest molecular weight distributions (MWD) and lowest thermal stability were obtained. High value of MWD was found for all the samples. The different thermal behavior observed for the sample prepared by using the highest amount of initiator is explained by the formation of polymer branched chain, induced by chain transfer to polymer processes. MALDI-TOF mass spectra resulted diagnostic of the homopolymers compositions displaying a series of peaks corresponding to oligomeric structures present in the polymeric samples. The thermal polymerization of 1 performed without employing catalyst was also investigated. Only low yields (4%) of short oligomers (from dimer to pentamer), bearing degraded POSS cages, were isolated.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: European Polymer Journal - Volume 43, Issue 12, December 2007, Pages 4898-4904
Journal: European Polymer Journal - Volume 43, Issue 12, December 2007, Pages 4898-4904
نویسندگان
Sandra Lo Schiavo, Placido Mineo, Paola Cardiano, Pasquale Piraino,