Coatings
·
2017
·Vol. 7
·期 10
·159
·
IF 2.175
Shaolong Li,Changlian Xu,Wenfeng Yang,Qingru Tang
We report an efficient and green approach to synthesize a linear castor oil-based polyurethane (CPU) without using any solvent or catalyst. Diol monomers were first synthesized by the aminolysis reaction between castor oil and diamines; this was accomplished within 6 h at 130 °C. Polymerization of the diols and isocyanate was further confirmed by Fourier transform infrared (FTIR),1H-nuclear magnetic resonance (1H-NMR), and gel permeation chromatography analyses. The resultant CPUs showed a good thermal stability with an initial degradation temperature higher than 300 °C, and their mechanical and wood bonding property can be modulated by the structures of diamine. In addition, the CPUs possessed a satisfying water resistance property with the water absorption amount lower than 2%. The green conversion of castor oil to thermoplastic polyurethane affords new opportunities in bio-based industries.Keywords:castor oil;linear polyurethane;catalyst-free;solvent-free
研究领域:
材料科学
·
绿色化学
✓ 已验证
DOI
高影响因子
CARBOHYDRATE RESEARCH
·
2024
·
IF 2.4
Xiao Du,Tengfei Li,Lumei Wang,Dezhang Ren,Zhibao Huo
In recent years, the research on the conversion of chitin to high value-added chemicals has attracted more and more attention. At present, the method of preparing lactic acid from chitin mostly uses strong base or catalyst. The reaction system under alkaline condition not only corrodes the container but also easily harms the human body. Herein, a simple and effective method to convert chitin to organic acids in catalyst and base-free conditions is developed. The use of H 2 O 2 only can efficiently convert chitin to organic acids in the absence of bases and catalysts. Under the optimal conditions of 30 mg chitin, 2.1 mL water, 0.9 mL H 2 O 2 at 230 °C for 1.5 h, the lactic acid yield of chitin can reach 58.2 % and the total organic acid yield can reach 84.0 %. This work provides an efficient method for the resource utilization of chitin biomass.
研究领域:
生物化学
·
生物质能
·
绿色化学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Zhengbiao Liu,Dechao Hu,Chengyu Zheng,Kanghua Yu,Xiancheng Zhang,Wenshi Ma
Silicone elastomers, as good sealants and adhesives, have been widely applied in protective coatings, architectural decoration, electronic packaging, and other fields. However, the traditional cross-linking of silicone elastomers is highly dependent on toxic catalysts or heavy metals, which may inevitably lead to severe environmental pollution. Moreover, most silicone elastomers suffer from a poor adhesive performance. In this study, inspired by the high adhesion properties of mussels, an eco-friendly and catalyst-free silicone elastomer with high adhesion properties was prepared by using dopamine as a cross-linker and amino-functionalized polysiloxane as a base. Under mild conditions (pH = 8.5), dopamine was self-polymerized and underwent Michael addition and Schiff base reactions with amino groups to form robust elastomers. It was found that the cross-linking degree gradually increases with the dopamine content increasing from 2 to 6%, and the solvent resistance and thermal stability exhibit significant improvement. Meanwhile, the tensile strength increased by 245% from 0.22 to 0.77 MPa. Especially, the as-obtained silicone elastomers have excellent adhesion to different materials. The lap shear strength with aluminum substrates (1.09 MPa) is 3.6 times higher than that of conventional silicone elastomers. The development of catalyst-free bioinspired silicone elastomers with high adhesion may shed light on the research of eco-friendly silicone materials and offer innovative insight for mussel-inspired adhesives.
研究领域:
材料科学
·
生物仿生学
✓ 已验证
产品关联
DOI
高影响因子
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
·
2024
·
IF 6.9
Zhongqing Shen,Zixian Jia,Kunpeng Yu,Jing Xie,Lijiao Qin,Lin Gao,Baozhong Li,Xuehai Wang,Jianzhong Yin
Depolymerization shows promise as a strategy for converting waste plastic into monomers that can be used for repolymerization. However, catalytic approaches would be more complex and expensive due to catalyst separation, recovery, and recycling. Here, we present a CO 2 -enhanced subcritical methanolysis method without catalyst that can generate monomer from poly(ethylene terephthalate)(PET). The synergistic effect of CO 2 on the subcritical methanolysis process for PET depolymerization was investigated including the CO 2 initial pressure, reaction temperature and reaction time. Under subcritical conditions, the optimal reaction parameters with PET conversion ratio of 100% and DMT yield of 79.1% are as follows: temperature of 220℃, methanol to PET mass ratio of 6:1 and reaction time of 50 min. Moreover, through the analysis of experimental data, it was concluded that the depolymerization reaction follows a first-order kinetics, with the reaction rate being 2–3 times faster than the traditional process. However, the apparent activation energy for both reactions is found to be similar, with values of 135.1 kJ·mol −1 and 146.2 kJ·mol −1 , respectively.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Nature Communications
·
2021
·Vol. 12
·期 1
·1-9
·
IF 14.919
Liang Chu,Chen Yun,Wu Min,Wang Kai,Zhang Wenkui,Gan Yongping,Huang Hui,Chen Jian,Xia Yang,Zhang Jun,Zheng Shiyou,Pan Hongge
Environmentally benign synthesis of graphite at low temperatures is a great challenge in the absence of transition metal catalysts. Herein, we report a green and efficient approach of synthesizing graphite from carbon dioxide at ultralow temperatures in the absence of transition metal catalysts. Carbon dioxide is converted into graphite submicroflakes in the seconds timescale via reacting with lithium aluminum hydride as the mixture of carbon dioxide and lithium aluminum hydride is heated to as low as 126 °C. Gas pressure-dependent kinetic barriers for synthesizing graphite is demonstrated to be the major reason for our synthesis of graphite without the graphitization process of amorphous carbon. When serving as lithium storage materials, graphite submicroflakes exhibit excellent rate capability and cycling performance with a reversible capacity of ~320 mAh g –1 after 1500 cycles at 1.0 A g –1 . This study provides an avenue to synthesize graphite from greenhouse gases at low temperatures.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
MOLECULES
·
2023
·Vol. 28
·期 9
·3948
·
IF 4.6
Cong Sun,Hui Liu,Yanran Chen,Xianzhi Wei,Shaohua Liang
As a natural polyphenolic compound, chlorogenic acid (CGA) has attracted increasing attention for its various biological activities, such as antioxidant, liver protection, intestinal barrier protection, and effective treatment of obesity and type II diabetes. However, the poor solubility of CGA in hydrophobic media limits its application in the food, drug and cosmetic industries. In order to obtain new hydrophobic derivatives, a highly efficient synthesis approach of CGA oleyl alcohol ester (CGOA) under non-catalytic and solvent-free conditions was developed in this study. The influences of reaction temperature, reaction time, substrate molar ratio, and stirring rate on the CGA conversion were investigated. The results showed that the optimal conditions were as follows: reaction temperature 200 °C, reaction time 3 h, molar ratio of CGA to oleyl alcohol 1:20, and stirring rate 200 rpm. Under these conditions, the CGA conversion could reach 93.59%. Then, the obtained crude product was purified by solvent extraction and column chromatography, and the purify of CGOA was improved to 98.72%. Finally, the structure of CGOA was identified by FT-IR, HPLC-MS and NMR. This study provides a simple and efficient strategy for the preparation of CGOA with the avoidance of catalysts and solvents.Keywords:chlorogenic acid;chlorogenic acid oleyl alcohol ester;esterification;non-catalytic synthesis
研究领域:
食品科学
·
药物化学
·
天然产物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMER
·
2020
·
IF 4.231
Shuaipeng Wang,Na Teng,Jinyue Dai,Jingkai Liu,Lijun Cao,Weiwei Zhao,Xiaoqing Liu
Fabrication of mechanically robust and catalyst-free vitrimers is of great importance, but often challenging. Herein, a facile strategy to achieve this goal by incorporation of intramolecular hydrogen bonds into the dynamic covalent network is demonstrated. Specifically, glycidyl methacrylate (GMA) is reacted with bio-renewable malic acid (MA) to generate a UV-curable resin containing ester linkages. On account of the proximity between the α -carbonyl and β -hydroxyl groups in MA, six-membered-ring intramolecular hydrogen bonds ( O-H⋯O=C ) are formed in the cross-linked network. This formation of intramolecular hydrogen bonds endows the network with enhanced and outstanding mechanical properties , showing tensile strength and Young's modulus of 117.7 MPa and 3.66 GPa, respectively. Meanwhile, the network is able to efficiently alter its topology without external catalyst through transesterifications reactions at high temperatures. We attributed this phenomenon to the presence of intramolecular hydrogen bonds which make the α -carbonyl carbon more positive and be more reactive towards nucleophilic attack, and thus facilitate the transesterification reaction. This work suggests a promising route to achieve catalyst-free thermosets with superior mechanical performances, good self-healing ability and reprocessability.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Coatings
·
2023
·Vol. 13
·期 1
·110
·
IF 3.4
Xixi Yu,Yun Hu,Wen Lei,Chengguo Liu,Yonghong Zhou
Developing environmentally friendly UV-curable polymers with multi-functionality is very significant for sustainable development and environmental protection. In this work, a novel tung-oil-based UV-curable oligomer (TOMAH) was synthesized by Diels–Alder and ring-opening reactions via microwave technology. Subsequently, catalyst-free self-healing UV-curable materials based on a maleate monoester transesterification (MMETER) were developed by co-photopolymerization of TOMAH and hydroxyethyl methacrylate (HEMA). The obtained UV-cured materials possessed a high glass transition temperature (Tg> 81 °C), excellent adhesion (grade 1), and flexibility (2 mm). Particularly, the outstanding photopolymerization activity of the UV-curable resins was proved by UV-curing kinetics. In addition, dynamic transesterifications occurred without an external catalyst at a moderate temperature, resulting in good self-healing properties (with a scratch-repair efficiency of 78.6–93.3%) and shape-memory properties for the obtained UV-cured materials. This work combines the multiple advantages of biomass raw material, microwave synthesis technology, UV-curing method, and multifunctional polymers, thus providing an innovative strategy to fabricate sustainable and intelligent coatings.Keywords:UV-curable coatings;self-healing;tung oil;catalyst-free;microwave technology
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
WASTE MANAGEMENT
·
2025
·
IF 7.1
Tianxiang Deng,Yi Chen,Delong Hou
The recycling of discarded THHN cables generates a substantial amount of mixed PVC/PA waste plastics, presenting a significant challenge to achieving sustainable development. In this study, we present a simple, catalyst-free, and scalable approach for upcycling all components of mixed PVC/PA waste. This method leverages HCl released from PVC during hydrothermal treatment to catalyse the cleavage of amide bonds in PA, converting mixed PVC/PA waste into valuable platform chemicals (over 80 % product yield) and carbon black within 30 min. Our work demonstrates a high-value recycling process for mixed PVC/PA waste in discarded THHN cables, reducing the generation of harmful Cl-containing waste, mitigating environmental pollution caused by mixed plastics, and offering valuable insights for the recycling of other PVC-containing mixed plastic wastes.
研究领域:
环境科学
·
材料工程
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2019
·Vol. 7
·期 30
·18039-18049
·
IF 10.733
Qiong Li,Songqi Ma,Sheng Wang,Wangchao Yuan,Xiwei Xu,Binbo Wang,Kaifeng Huang,Jin Zhu
Dynamic covalent networks offer the favorable features of cross-linked polymers as well as the functions of reprocessing, recycling, self-healing, reshaping, and welding; however, it is a challenge to design readily monomer-recovery, highly malleable, catalyst-free, dynamic materials. Here we report the first design of acetal dynamic networks to address this challenge. Acetal dynamic networks were built via the catalyst-free “click” addition of polyol and a commercial divinyl ether without releasing small molecules. Small-molecule model compounds demonstrated thermally-induced acetal exchange without a catalyst. There are two mechanisms for the dynamic exchange of acetal: one is the metathesis of acetal, another is transacetalization. Acetal dynamic covalent networks exhibited excellent malleability and recyclability. They presented rapid stress relaxation at high temperatures. Hot press recovery can be achieved in 10 min at 150 °C. Meanwhile, the starting material was recovered with 92% recovery in 1 h under hot water treatment at 100 °C, and could be recross-linked with a commercial divinyl ether to obtain an acetal network. The acetal networks recovered by the two methods maintained the original structure and performance. An acetal dynamic linkage will open up a new way for the development of catalyst-free dynamic covalent networks and enrich acetal chemistry.
研究领域:
材料科学
·
有机化学
✓ 已验证
产品关联
DOI
高影响因子
Green Chemistry Letters and Reviews
·
2019
·
IF 2.754
Adil Omar,Keyume Ablajan
A simple, efficient, eco-friendly and catalyst-free procedure was developed for the construction of novel coumarin-spiro[indoline-3,4'-pyran] conjugates via three-component reactions of various synthetic beta-ketoesters with isatins and malononitrile in aqueous medium. In addition to operational simplicity and absence of tedious separation procedures, being catalyst–free is the prominent advantage of this method.
研究领域:
有机化学
·
药物化学
✓ 已验证
DOI
高影响因子
Applied Materials Today
·
2025
·
IF 6.9
Weiqiang Han,Xia Liao
In this work, we reported a facile approach for fabricating external catalyst-free poly (ethylene 2,5-furandicarboxylate)/poly (trimethylene carbonate) (PEF/PTMC) blend vitrimer through two-step reactive blending by the addition of 2,2-bis(hydroxymethyl) 2,2′,2″-nitrilotriethanol (BIS-TRIS) and N, N′-tetraglycidyldiaminodiphenyl methane (TGDDM) for the first time. This method breaks through the difficulties of the traditional preparation method of vitrimer materials that must require the addition of metal catalyst, thus realizing the concept of green chemistry. At the same time, it also breaks through the difficulty of poor compatibility in the traditional blend preparation methods. Swelling and FTIR tests confirmed the presence of the dynamic cross-linking structure consisting of PEF and PTMC chains, while rheological analysis shows that the formed cross-linked network in PEF/PTMC blend can significantly improve its melt strength and make it could be foamed by supercritical carbon dioxide. An expansion ratio about 10-fold and microcellular foam with a uniform cell morphology can be obtained for PEF/PTMC composite vitrimer when the PTMC content and the gel content was less than 20% and 50%, respectively. Moreover, PEFMC foams possess greater compressive strength than that of commercial PET foams, exhibiting excellent mechanical properties. TGA and tensile experiments revealed that PEF/PTMC composite vitrimer exhibited excellent mechanical performance and thermal stability. Meanwhile, PEF/PTMC composite vitrimer still maintain the ability of excellent reprocessability. This work provides a practical green method to guide the design of novel polymer blends with improved miscibility, mechanical properties and sustainability by a dynamic cross-linking network.
研究领域:
材料科学
·
绿色化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）