کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5200961 | 1502880 | 2016 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Lipase-mediated degradation of poly-ε-caprolactone in toluene: Behavior and its action mechanism
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Lipase-catalyzed hydrolysis of poly(É-caprolactone) (PCL) in toulene was investigated. PCL with number-average molecular weight (Mn) 10,000 g molâ1 was hydrolyzed using immobilized Candida antarctica lipase B (CALB). The increase in PCL concentration led to a decrease in degradation rate. Enhanced rate was observed when reaction temperature was increased from 30 to 50 °C. Enzymatic chain scission of PCL yielded cyclic dicaprolactone, tricaprolactone, tetracaprolactone and oligomers with Mn less than â¼1000 g molâ1. Catalytic formation of cyclic lactones via back-biting mechanism in low water content environment was attributed to CALB. Its hydrolysis of PCL displayed consecutive random- and chain-end scission with time from detailed thermal, molecular weight and structural analyses. Apparent activation energy, Ea for hydrolysis was 45 kJ molâ1 i.e. half of that reverse reaction. Dicaprolactone and oligomers from hydrolysis readily re-polymerized to produce mid-range polymer with Mn 1400 g molâ1 after 36 h in the same reaction medium.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer Degradation and Stability - Volume 133, November 2016, Pages 182-191
Journal: Polymer Degradation and Stability - Volume 133, November 2016, Pages 182-191
نویسندگان
Muhammad Haziq Aris, Mohamad Suffian Mohamad Annuar, Tau Chuan Ling,