Aris, M.H. and Annuar, M.S.M. and Ling, T.C. (2016) Lipase-mediated degradation of poly-ε-caprolactone in toluene: Behavior and its action mechanism. Polymer Degradation and Stability, 133. pp. 182-191. ISSN 0141-3910, DOI https://doi.org/10.1016/j.polymdegradstab.2016.08.015.
Full text not available from this repository.Abstract
Lipase-catalyzed hydrolysis of poly(ɛ-caprolactone) (PCL) in toulene was investigated. PCL with number-average molecular weight (Mn) 10,000 g mol−1 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 ∼1000 g mol−1. 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 mol−1 i.e. half of that reverse reaction. Dicaprolactone and oligomers from hydrolysis readily re-polymerized to produce mid-range polymer with Mn 1400 g mol−1 after 36 h in the same reaction medium.
| Item Type: | Article |
|---|---|
| Funders: | University of Malaya for research funding PG 080-2012B and RG330-15AFR |
| Uncontrolled Keywords: | Poly(ɛ-caprolactone); Lipase; Enzymatic degradation; Organic solvent; Cyclic lactones; Scission mechanism |
| Subjects: | Q Science > QH Natural history > QH301 Biology |
| Divisions: | Faculty of Science > Institute of Biological Sciences |
| Depositing User: | Ms. Juhaida Abd Rahim |
| Date Deposited: | 08 Sep 2017 10:08 |
| Last Modified: | 08 Sep 2017 10:08 |
| URI: | http://eprints.um.edu.my/id/eprint/17776 |
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