Toward faster degradation for natural fiber reinforced poly(lactic acid) biocomposites by enhancing the hydrolysis-induced surface erosion
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- 作者：Lan Xie (1)
Huan Xu (1)
Ze-Pu Wang (1)
Xu-Juan Li (1)
Jing-Bin Chen (1)
Zi-Jing Zhang (1)
Hua-Mo Yin (1)
Gan-Ji Zhong (1)
Jun Lei (1)
Zhong-Ming Li (1) - 关键词：Poly(lactic acid) ; Natural fiber biocomposites ; Hydrolytic degradation ; Surface erosion ; Cellulose regeneration
- 刊名：Journal of Polymer Research
- 出版年：2014
- 出版时间：March 2014
- 年：2014
- 卷：21
- 期：3
- 全文大小：2,605 KB
- 作者单位：Lan Xie (1)
Huan Xu (1)
Ze-Pu Wang (1)
Xu-Juan Li (1)
Jing-Bin Chen (1)
Zi-Jing Zhang (1)
Hua-Mo Yin (1)
Gan-Ji Zhong (1)
Jun Lei (1)
Zhong-Ming Li (1)
1. College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, Sichuan, People’s Republic of China - ISSN：1572-8935
文摘
The poor and uncontrollable biodegradability of poly(lactic acid) (PLA)-based materials is one of the fundamental limitations for widening their applications. To regulate the degradation of PLA/ramie fiber biocomposites, the hydrophilicity of the composites was modified to attract more water attack by introducing water-soluble poly(ethylene glycol) (PEG). Analyses by characterization of sample size, weight loss and microstructure offered intensive information on the degradation behavior of PLA biocomposites. It was revealed that PEG indeed significantly enhanced the surface erosion process and thus facilitated the degradation rate. The biocomposite bar containing 15?wt% PEG completed degradation within 50?days, while only ~50?wt% mass lost for the control biocomposite sample without PEG. Morphological observation confirmed that PEG accelerated the penetration of outside water from the surface to the center driven by the diffusion-in process, which subsequently boosted the hydrolytic action of the PLA backbone ester groups. Our results indicated that the PEG induced water penetration governed the overall degradation kinetics. As a strong response to the degradation, the stiffness of the biocomposite bars suffered from drastic decrease while T g varied in a climbing trend within the early stage. Microscopic examination of degradation solution formed during hydrolytic degradation of the PLA biocomposites suggested oligomers or lactic acid monomers were released to the solutions. It was of great interest to observe PEG dissolved in the alkaline solution speeded the ramie fibers breaking down to tiny fragments and cellulose macromolecules which further regenerated into cellulose aggregates in various fantastic appearances like coral-like leaves and pine needles. Our success in regulating the degradation of PLA biocomposites also provides an instructive approach for other PLA based materials. Figure Hydrolytic degradation of PLA/ramie fiber biocomposites is successfully regulated by introducing PEG, permitting faster degradation for biocomposites due to the accelerated surface erosion process, as well as enhanced dissolution for ramie fibers which further regenerate into cellulose aggregates.