Lipase-mediated degradation of poly-ɛ- caprolactone in toluene: Behavior and its action mechanism / Muhammad Haziq Aris
Poly-ɛ-caprolactone (PCL) is a semi-crystalline polyester, hydrophobic in nature and highly degradable. However, these properties make it unsuitable for many applications. Blending of PCL oligomers with other polymer(s) helps to improve its characteristics. It is suggested that by degrading the l...
| Main Author: | |
|---|---|
| Format: | Thesis |
| Published: |
2017
|
| Subjects: | |
| Online Access: | http://studentsrepo.um.edu.my/9581/ http://studentsrepo.um.edu.my/9581/1/Muhammad_Haziq_Aris.pdf http://studentsrepo.um.edu.my/9581/6/haziq.pdf |
| _version_ | 1848773956600856576 |
|---|---|
| author | Muhammad Haziq , Aris |
| author_facet | Muhammad Haziq , Aris |
| author_sort | Muhammad Haziq , Aris |
| building | UM Research Repository |
| collection | Online Access |
| description | Poly-ɛ-caprolactone (PCL) is a semi-crystalline polyester, hydrophobic in nature
and highly degradable. However, these properties make it unsuitable for many
applications. Blending of PCL oligomers with other polymer(s) helps to improve its
characteristics. It is suggested that by degrading the long PCL chain into moderate
length would permit the blending and functionalization processes to be more amenable
to control variables. In this study, lipase-catalyzed hydrolysis of 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 hours in the same reaction medium. These versatile
oligomers can be applied as integral components for processes such as copolymerization
or functionalization of valuable compounds. |
| first_indexed | 2025-11-14T13:50:39Z |
| format | Thesis |
| id | um-9581 |
| institution | University Malaya |
| institution_category | Local University |
| last_indexed | 2025-11-14T13:50:39Z |
| publishDate | 2017 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | um-95812019-08-04T20:58:42Z Lipase-mediated degradation of poly-ɛ- caprolactone in toluene: Behavior and its action mechanism / Muhammad Haziq Aris Muhammad Haziq , Aris Q Science (General) QH301 Biology Poly-ɛ-caprolactone (PCL) is a semi-crystalline polyester, hydrophobic in nature and highly degradable. However, these properties make it unsuitable for many applications. Blending of PCL oligomers with other polymer(s) helps to improve its characteristics. It is suggested that by degrading the long PCL chain into moderate length would permit the blending and functionalization processes to be more amenable to control variables. In this study, lipase-catalyzed hydrolysis of 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 hours in the same reaction medium. These versatile oligomers can be applied as integral components for processes such as copolymerization or functionalization of valuable compounds. 2017-05 Thesis NonPeerReviewed application/pdf http://studentsrepo.um.edu.my/9581/1/Muhammad_Haziq_Aris.pdf application/pdf http://studentsrepo.um.edu.my/9581/6/haziq.pdf Muhammad Haziq , Aris (2017) Lipase-mediated degradation of poly-ɛ- caprolactone in toluene: Behavior and its action mechanism / Muhammad Haziq Aris. Masters thesis, University of Malaya. http://studentsrepo.um.edu.my/9581/ |
| spellingShingle | Q Science (General) QH301 Biology Muhammad Haziq , Aris Lipase-mediated degradation of poly-ɛ- caprolactone in toluene: Behavior and its action mechanism / Muhammad Haziq Aris |
| title | Lipase-mediated degradation of poly-ɛ- caprolactone in toluene: Behavior and its action mechanism / Muhammad Haziq Aris |
| title_full | Lipase-mediated degradation of poly-ɛ- caprolactone in toluene: Behavior and its action mechanism / Muhammad Haziq Aris |
| title_fullStr | Lipase-mediated degradation of poly-ɛ- caprolactone in toluene: Behavior and its action mechanism / Muhammad Haziq Aris |
| title_full_unstemmed | Lipase-mediated degradation of poly-ɛ- caprolactone in toluene: Behavior and its action mechanism / Muhammad Haziq Aris |
| title_short | Lipase-mediated degradation of poly-ɛ- caprolactone in toluene: Behavior and its action mechanism / Muhammad Haziq Aris |
| title_sort | lipase-mediated degradation of poly-ɛ- caprolactone in toluene: behavior and its action mechanism / muhammad haziq aris |
| topic | Q Science (General) QH301 Biology |
| url | http://studentsrepo.um.edu.my/9581/ http://studentsrepo.um.edu.my/9581/1/Muhammad_Haziq_Aris.pdf http://studentsrepo.um.edu.my/9581/6/haziq.pdf |