Papers by Author: Zhi Ming Yu

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Authors: Fu Rong Shan, Meng Qi Wang, Yang Bai, Zhi Ming Yu
Abstract: The research presented in the paper focuses on the specific process of Gutta-percha extraction and refinement. Gutta-percha was extracted from the residues of leaves, which is based on the comprehensive utilization technology of Eucommia Ulmoides leaves. After extracted and separated chlorophyll, β-carotene, lignans, aucubin, chlorogenic acid, flavonoid, polysaccharide and proteins, etc. with the method of Multi-stage Countercurrent Extraction, the green leaves changed into the residues, which was then steeped in petroleum ether (whose boiling range is from 60 to 90°C) and generated precipitation in acetone. The results of this research indicate that: Gutta-percha extracted from the residues owns light color, which resolves the big issue that the gum was restricted for deep color in exportation. Besides, the yield of the gum in this experiment is approximate 2.0%, the increasing rate rising by 17.6% compared with 1.7% of other immediate extraction methods’. What’s more, the cost of the process flows introduced in the paper is lower than others, with less consumption, less waste and more efficient solvent circle utilization. And a new way for gutta-percha extraction was presented.
Authors: Xiao Juan Jin, Wu Yu, Zhi Ming Yu
Abstract: lignin (L)-based phenolic prepolymers with different phenol (P) substitution degrees were synthesized using the modified(M) L with laccase. It was found that the ML showed lower molecular value, polydispersity and higher reactivity compared to unmodified sample, and up to 30% of phenol can be substituted by MF to give LPF wood adhesive having better bonding strength in comparison to a control unmodified lignin phenol formaldehyde wood adhesive. MF was characterized using FTIR and GPC. FTIR showed that after the treatment of laccase, the methoxyl group increased, which was mainly due to the demethylation, and laccase/mediator system made the ether bonds of L cleave to produce more alcohol hydroxyl, as a result, the reactivity of ML was improved.
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