Preparation of an environmentally friendly antifouling degradable polyurethane coating material based on medium-length fluorinated diols

A novel medium-length fluorinated diols and poly(L-lactide) (PLLA) were synthesized via Michael addition reaction and ring-opening polymerization, respectively. Subsequently, Synthetic medium-length fluorinated diols and PLLA were combined to prepare new polyurethane composites with degradability and low surface energy. The compositional analysis and structural characterization of synthetic materials were characterized by using fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectra (¹HNMR). Thermogravimetric analysis(TGA) indicated that the introduction of medium-length fluorinated diols improved the thermal stability of the polyurethane. The biodegradation and low surface energy of the polyurethane were investigated by static hydrolysis experiment and water contact angle test. It was found that the degradation rate of the polyurethane increased as measurement time went on when the PLLA content was under 40%, and the water contact angle increased from 71.12° to 108.24° with the increase of fluorine content, which indicated that the degradable and low surface energy polyurethane has a potential as a coating material for a marine antifouling coating application.     

Liquid–liquid equilibria of the ternary system water + acetic acid + dimethyl adipate

Liquid–liquid equilibrium (LLE) data of water + acetic acid + dimethyl adipate have been determined experimentally at 298.15, 308.15 and 318.15 K. Complete phase diagrams were obtained by determining binodal curve and tie-lines. The reliability of the experimental tie-line data was confirmed by using the Othmer-Tobias correlation. UNIFAC and modified UNIFAC models were used to predict the phase equilibrium in the system using the interaction parameters determined from experimental data of CH₂, CH₃COO, CH₃, COOH, and H₂O functional groups. Distribution coefficients and separation factors were evaluated for the immiscibility region.     

Additives for controlled degradation of agricultural plastics: ENVIROCARETM

ENVIROCARE^TM additives are specialty chemicals that can be added to conventional thermoplastic polymers to obtain degradable agricultural plastic articles. Their main benefits are connected with their possible incorporation in “commodity plastics”. This allows the production of degradable agriculture plastic articles processable with standard manufacturing machines, without negative effects on the main properties of the plastic article and with evident costs advantages. Furthermore, required outdoor exposure lifetimes for different articles and different environmental conditions can be modulated with the incorporation of the appropriate additive loading in the plastic and with combinations of selected stabilizers. Mulch films, small tunnel films, banana bags and sleeves, direct covers, non-woven, ropes, twines and pots are convenient agricultural applications for this technology. ENVIROCARE^TM products induce plastic degradation following a two steps mechanism: first the plastic is photo- and thermo-oxidized during the outdoor exposure; once the degradation process has been activated by light or heat, ENVIROCARE^TM acts by increasing the degradation rate and degradation continues until the article is totally degraded. Since degradation is both photolytically and thermally triggered, degradation occurs both at the surface and in the soil. Experimental laboratory results allow the assessment of the contribution of different important parameters - i.e. type of polymer, type of article, presence of other stabilizers/additives or pigments, different environmental conditions- on the control of the article lifetime and degradation. Field exposure in different environments integrates the test results and allows for the design of the additive systems adapted to the specific needs.     

低共熔溶剂回收锂离子电池正极材料的研究

废旧锂离子电池不仅造成了严重的资源浪费同时还带来严重的环境污染问题.传统锂离子电池材料回收方法存在高能耗、高成本以及二次污染等不足.本文成功制备出乙二醇/氯化锌低共熔溶剂(DES),利用其对金属氧化物优秀的溶解能力,用于三元锂离子电池正极材料有价金属的回收,并分析了不同氯化锌浓度对低共熔溶剂热物性及其浸取能力的影响,对...     

A simple and environmentally benign synthesis of polypyridine-polycarboxylic acids

An oxidation method using dilute nitric acid solutions under solvothermal conditions has been developed to synthesise a series of polypyridine-polycarboxylic acids. It has been successfully applied to a range of methyl substituted polypyridines including symmetrical and asymmetrical 2,2′-bipyridines; 2,2′:6′,2″-terpyridines and; 2,2′:6′,2″:6″,2?-tetra-pyridines and yields crystalline polypyridine-polycarboxylic acids in a single step. Simple product recovery through filtration yields a recyclable filtrate. More forcing conditions led to demethylation of the polypyridine ligand most probably via decarboxylation. This simple approach avoids potentially harmful metal-based oxidants and negates any issues associated with the disposal of their resultant (hazardous) waste.     

Eco-friendly synthesis of guanidinyltetrazole compounds and 5-substituted 1H-tetrazoles in water under microwave irradiation

We have developed simple, short time, cost effective, purification of products by non-chromatographic methods and environmentally benign protocol for the synthesis of guanidinyltetrazoles and 5-substituted 1H-tetrazoles derivatives via [2,3]cyclo-addition reaction of nitriles and azide derivatives in water under microwave irradiation. All the synthesized products are screened for their in vitro antimicrobial activity. The synthesized compounds were obtained in excellent yield (85–98%).     

Effective and Green One‐Pot Multicomponent Synthesis of Novel Derivatives of 4H‐Pyrans in the Presence of Hexamethylenetetramine as Catalyst in Water Medium

Hexamethylenetetramine catalyzes synthesis of new polyfunctionalized 4H‐pyrans by the reaction of aromatic aldehyde, malononitrile, and β‐keto esters via one‐pot three‐component procedure in water medium. Addition of reactants was performed by two methods led to achieve similar results. Using hexamethylenetetramine in catalytic amount not only represents the economic face of the reaction but also due to the use of water, a green and safe reaction condition is organized. Thus, the current strategy provides the benefits of high productivity, convenient operation, and environmental friendliness. The structure of all products were proved by elemental analysis, IR, ¹H NMR, and ¹³C NMR spectroscopy.     

Facile microwave-assisted synthesis of thioformamides from isocyanides and carbon disulfide

A new, fast, solvent-free and efficient method is provided to prepare thioformamides by reacting isocyanides derivatives, carbon disulfide and benzylamine under microwave irradiation.     

酰胺型改性菜籽油润滑添加剂对钢-钢摩擦副和钢-铝摩擦副摩擦磨损性能的影响

以三乙醇胺和菜籽油为原料,合成了一种环境友好的酰胺型改性菜籽油润滑添加剂(NRO),并利用红外光谱对其主要官能团进行了鉴定;分别采用四球摩擦磨损试验机和SRV摩擦磨损试验机考察了含NRO添加剂的菜籽油对钢-钢摩擦副和钢-铝摩擦副摩擦磨损性能的影响,用扫描电子显微镜观察和分析了钢球磨斑表面形貌,同时采用X射线光电子能谱仪分析了铝合金磨痕表面典型元素的化学状态,探讨了酰胺型改性菜籽油润滑添加剂的减摩抗磨机理.结果表明:含酰胺型改性菜籽油添加剂NRO的菜籽油对钢-钢摩擦副和钢-铝摩擦副均表现出良好的抗磨减摩作用;其作用机理在于,酰胺型改性菜籽油添加剂具有较强的极性、易在金属表面形成吸附膜,同时在摩擦过程中形成由含有机氮、亚硝基或硝酸根化合物组成的高强度聚合物膜.