کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5204069 1381948 2008 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The thermal degradation of poly(vinyl acetate) and poly(ethylene-co-vinyl acetate), Part I: Experimental study of the degradation mechanism
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
The thermal degradation of poly(vinyl acetate) and poly(ethylene-co-vinyl acetate), Part I: Experimental study of the degradation mechanism
چکیده انگلیسی

The thermal degradation mechanism of poly(vinyl acetate) (PVAc) and poly(ethylene-co-vinyl acetate) (EVA) copolymers was investigated with solid-state NMR, thermogravimetry coupled with mass spectrometry and differential thermal analysis. Between 300 and 400 °C acetic acid is eliminated (deacetylation), leaving a highly unsaturated residue or polyene. The deacetylation of PVAc is autocatalytic. Upon incorporation of ethylene entities into the polymer backbone, autocatalysis disappears. Between 400 and 500 °C, the polyene will degrade further by chain scission reactions in inert conditions or aromatise in an oxidative environment into a char, and oxidised eventually into CO2 beyond 500 °C.In inert conditions, the deacetylation step as well as the chain scission reaction shows endothermic effects. In an oxidative environment, large exothermal effects are found for each degradation step. This indicates the occurrence of additional oxidation reactions during deacetylation, an important reorganisation of the polyene during char formation and oxidation of the latter into CO2.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer Degradation and Stability - Volume 93, Issue 4, April 2008, Pages 800-810
نویسندگان
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