کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5181677 1380969 2014 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Role of end-groups and catalyst in polyester cyclodepolymerization and cycle-chain equilibria
ترجمه فارسی عنوان
نقش گروه های انتهایی و کاتالیزور در پلیمر سیلیکود پلیمریزاسیون و تعادل چرخه زنجیره ای
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
چکیده انگلیسی

The influence of polyesters end-groups on cyclic oligoester formation is investigated using a series of hydroxy-, carboxy- and methylester-terminated aliphatic polyesters, in the presence of various ester interchange catalysts. The presence of hydroxy end-groups is the preponderant factor on cyclodepolymerization kinetics. This indicates that the main reaction is the intramolecular hydroxy-ester interchange reaction between hydroxy end-groups and ester functions in the chain. Carboxy-ester and ester-ester interchanges play a minor role, as the cycle-chain equilibrium is reached only very slowly when carboxy- or ester-terminated polyesters are reacted. High temperature and the presence of tin catalysts are also favorable factors, while, as expected, dilution shifts the equilibrium toward the formation of high yields of cyclic oligoesters. A mechanism is proposed, based on the reverse of the “coordination-insertion” mechanism established for the ring-opening polymerization of lactones.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 55, Issue 1, 14 January 2014, Pages 73-82
نویسندگان
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