کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5185695 | 1381085 | 2007 | 12 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Solvent induced morphologies of poly(methyl methacrylate-b-ethylene oxide-b-methyl methacrylate) triblock copolymers synthesized by atom transfer radical polymerization
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
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چکیده انگلیسی
Poly(methyl methacrylate-b-ethylene oxide-b-methyl methacrylate) (PMMA-PEO-PMMA) triblock copolymers were synthesized using atom transfer radical polymerization (ATRP) and halogen exchange ATRP. PEO-based macroinitiators with molecular weight from Mn = 2000 to 35,800 g/mol were used to initiate the polymerization of MMA to obtain copolymers with molecular weight up to Mn = 82,000 g/mol and polydispersity index (PDI) less than 1.2. The macroinitiators and copolymers were characterized by gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR) spectroscopy. The melting temperature and glass transition temperature of the copolymers were measured by differential scanning calorimetry (DSC). Crystallinities of the PEO blocks were determined from the WAXS patterns of both homopolymers and block copolymers, which revealed the fragmentation of PEO blocks due to the folding of the PMMA chains. Interestingly, the fragmentation was less pronounced when cast on surfaces compared to that in bulk, as measured by GISAXS. Solvent casting was used to control the morphology of the copolymers, permitting the formation of various states including amorphous, induced micellar with a PMMA core and flower-like PEO arms, and a cross-linked gel. Atomic force microscopy (AFM) was used to visualize the different copolymer morphologies, showing micellar and amorphous states.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 48, Issue 25, 30 November 2007, Pages 7279-7290
Journal: Polymer - Volume 48, Issue 25, 30 November 2007, Pages 7279-7290
نویسندگان
Daniel J. Siegwart, Wei Wu, Monisha Mandalaywala, Magi Tamir, Traian Sarbu, Michael S. Silverstein, Tomasz Kowalewski, Jeffrey O. Hollinger, Krzysztof Matyjaszewski,