کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5189845 | 1381193 | 2005 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Kinetic study on reversible addition-fragmentation chain transfer (RAFT) process for block and random copolymerizations of styrene and methyl methacrylate
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
The degenerative (exchange) chain transfer constant Cex was determined for the dithioacetate-mediated living radical block and random copolymerizations of styrene (St) and methyl methacrylate (MMA) at 40 °C. The addition of the polystyrene (PSt) radical to a polymer-dithioacetate adduct (P-X) to form the intermediate radical (PSt-(X)-P) was (about twice) faster than that of the poly(methyl methacrylate) (PMMA) radical to form the intermediate radical PMMA-(X)-P. The fragmentation (release) of the PMMA radical from the PSt-(X)-PMMA intermediate formed at the initiating stage of block copolymerization was much (about 100 times) faster than the release of the PSt radical, explaining why the block copolymerization of MMA from a PSt-dithiocarbonate adduct is not so satisfactory as that of St from a PMMA-dithiocarbonate adduct. In the random copolymerization, there was implicit penultimate unit effect on the exchange chain transfer process, which appeared in the addition process but not in the fragmentation process.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 46, Issue 23, 14 November 2005, Pages 9762-9768
Journal: Polymer - Volume 46, Issue 23, 14 November 2005, Pages 9762-9768
نویسندگان
Keiji Kubo, Atsushi Goto, Koichi Sato, Yungwan Kwak, Takeshi Fukuda,