Polymers
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2018
·Vol. 10
·期 2
·133
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IF 2.935
Guiying Wu,Xiaoling Xu,Xin He,Yunjun Yan
Bio-based polyurethane (PU) composites with superior thermal and mechanical properties have received wide attention. This is due to the recent rapid developments in the PU industry. In the work reported here, novel nano-composites with graphene oxide (GO)-modifiedSapium sebiferumoil (SSO)-based PU has been synthesized via in situ polymerization. GO, prepared using the improved Hummers method from natural graphene (NG), and SSO-based polyol with a hydroxyl value of 211 mg KOH/g, prepared by lipase hydrolysis, were used as raw materials. The microstructures and properties of GO and the nano-composites were both characterized using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and tensile tests. The results showed that GO with its nano-sheet structure possessed a significant number of oxygen-containing functional groups at the surface. The nano-composites containing 1 wt % GO in the PU matrix (PU1) exhibited excellent comprehensive properties. Compared with those for pure PU, the glass transition temperature (Tg) and initial decomposition temperature (IDT) of the PU1 were enhanced by 14.1 and 31.8 °C, respectively. In addition, the tensile strength and Young’s modulus of the PU1 were also improved by 126% and 102%, respectively, compared to the pure PU. The significant improvement in both the thermal stability and mechanical properties for PU/GO composites was attributed to the homogeneous dispersion and good compatibility of GO with the PU matrix. The improvement in the properties upon the addition of GO may be attributable to the strong interfacial interaction between the reinforcing agent and the PU matrix.Keywords:graphene oxide;Sapium sebiferumoil;polyurethane;nano-composites
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2020
·
IF 3.408
Yong He,Ying Zhou,Hongming Wu,Zhuyu Bai,Can Chen,Xiaolang Chen,Shuhao Qin,Jianbing Guo
In this work, the combined plasticization of functionalized epoxy soybean/tung oils anhydride (ESO/TOA) for jute fiber-reinforced polypropylene (PP) composites is investigated. The structure, thermal stability, crystallization behaviors and mechanical properties of PP/jute/ESO/TOA composites are characterized and tested in detail by Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and mechanical property tests. The tensile and flexural strengths of PP/jute/ESO/TOA composites slightly decrease while the impact strength significantly increases with the addition of ESO and TOA. The FTIR spectra show ESO and TOA from gel with TOA as the skeleton and ESO as the crosslinking agent. The PP/jute/ESO/TOA composites with a very rough structure is observed through SEM images, which is attributed to an extraordinary plasticization of ESO and TOA on the PP/jute composites. In addition, ESO and TOA markedly change the decomposition process and the crystallization temperature of PP/jute/ESO/TOA composites. This may be attributed to the formation of the gels, which restricts the deformation of the composites and stores more deformation energy.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2024
·
IF 8.2
Xiang Dong,Wenying Li,Changzhu Li,Otobong Donald Akan,Chancan Liao,Jie Cao,Lin Zhang
Lead (Pb) affects gene transcription, metabolite biosynthesis and growth in plants. The tung tree ( Vernicia fordii ) is highly adaptive to adversity, whereas the mechanisms underlying its response to Pb remain uncertain. In this work, transcriptomic and metabolomic analyses were employed to study tung trees under Pb stress. The results showed that the biomass of tung seedlings decreased with increasing Pb doses, and excessive Pb doses resulted in leaf wilting, root rot, and disruption of Pb homeostasis. Under non-excessive Pb stress, a significant change in the expression patterns of flavonoid biosynthesis genes was observed in the roots of tung seedlings, leading to changes in the accumulation of flavonoids in the roots, especially the upregulation of catechins, which can chelate Pb and reduce its toxicity in plants. In addition, Pb-stressed roots showed a large accumulation of VfWRKY55 , VfWRKY75 , and VfLRR1 transcripts, which were shown to be involved in the flavonoid biosynthesis pathway by gene module analysis. Overexpression of VfWRKY55 , VfWRKY75 , and VfLRR1 significantly increased catechin concentrations in tung roots, respectively. These data indicate that Pb stress-induced changes in the expression patterns of those genes regulate the accumulation of catechins. Our findings will help to clarify the molecular mechanism of Pb response in plants.
研究领域:
植物生理学
·
分子生物学
·
环境科学
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产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）