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Nim, Bunthoeun. Microwave-assited alcoholysis of polylactide and its applications. Doctoral Degree(Engineering and Technology). Thammasat University. Thammasat University Library. : Thammasat University, 2020.
Microwave-assited alcoholysis of polylactide and its applications
Name: Nim, Bunthoeun
keyword:
Chemical recycling
Abstract:
Chemical recycling of post-consumer bioplastic wastes, especially polyesters, has been of interest for recovering of small-sized products for use as value-added starting materials in other processes. Alcoholysis or transesterification of polylactide (PLA) with various alcohols and polymers, i.e., 1,2-ethanediol (EG), 1,3-propanediol (PDO), 1,4-butanediol (BDO), 1,2-propanediol (PG), glycerol, erythritol, xylitol, sorbitol, poly(ethylene glycol) (PEG), and poly (propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) (PGEG), is developed by using microwave reactor, in a presence of tetrabutyl orthotitanate (TBT) catalyst at various PLA/alcohol ratios. The alcoholyzed products were characterized by employing Fourier transform infrared (FTIR) spectroscopy, two-dimensional nuclear magnetic resonance (2D-NMR) spectroscopy, and proton nuclear magnetic resonance (1H-NMR) spectroscopy. The products compost of diol-capped lactate sequences with different length, i.e., lactate, dilactate, and polylactate. Monolactate is obtained at much higher contents than those of dilactate and polylactate, when excess amount of alcohols was used at a PLA/alcohol ratio of 1:1 wt/wt. However, monolactate content is decreased by changing the PLA/alcohol ratios from 1:1 to 4:1 wt/wt. In contrast, dilactate and polylactate contents are increased with an increase in the PLA/alcohol ratios. Efficiency and reactivity of the alcohols, in reacting and bonding with lactate sequences at a PLA/alcohol ratio of 1:1, are observed in an order, as follows: EG > PDO > PG > erythritol > glycerol > BDO > xylitol > sorbitol. An alcoholysis of PLA by high molecular weight PEG and PGEG produces only oligo-lactate sequences with different chain lengths. Interestingly, the alcoholysis of PLA also generates lactide from the chains back-biting reaction, whose content is increased by an increase in the PLA/alcohol ratios from 1:1 to 20:1 wt/wt. The alcoholyzed PLA products, with specific size and structures are then used as polyols starting materials in a preparation of lactide-based polyurethanes (PU). The products from alcoholysis with BDO at a PLA/diol ratio of 3:1 (LBDOT31) was chosen to react with 1,6-diisocyanatohexane (HDI), and BDO chain extender. The resulting PU shows elastic properties, whose elongation at break is higher than 540%, while tensile strength and modulus are slightly lower compared to neat PLA. These are suitable for use as either single component material, e.g., 3D-printing filaments and degradable adhesives, or as toughness-enhancing agents for brittle polymers, especially PLA.
Thammasat University. Thammasat University Library
Address:
BANGKOK
Email:
preserv@tu.ac.th
Name: Pakorn Opaprakasit
Role:
advisor
Created:
2020
Modified:
2023-02-10
Issued:
2023-02-10
วิทยานิพนธ์/Thesis
application/pdf
eng
DegreeName: Doctor of Philosophy
Level: Doctoral Degree
Descipline: Engineering and Technology
Grantor: Thammasat University
©copyrights Thammasat University
RightsAccess:
ใช้เวลา
0.025611 วินาที
Nim, Bunthoeun
| Title | Contributor | Type |
|---|---|---|
| Microwave-assited alcoholysis of polylactide and its applications
มหาวิทยาลัยธรรมศาสตร์ Nim, Bunthoeun | Pakorn Opaprakasit | วิทยานิพนธ์/Thesis |
Pakorn Opaprakasit