Environmentally Friendly Polyurethane Composites: Preparation, Characterization and Mechanical Properties

The waterborne polyurethane (PU) prepolymer was prepared based on isophorone diisocyanate (IPDI), polyester polyol (N220), dimethylol propionic acid (DMPA) and hydroxyethyl methyl acrylate (HEMA). The modified waterborne polyurethane–acrylate (PUA) emulsions were obtained with different proportions of acrylate (butyl acrylate and methyl methacrylate) and initiating agent by in situ dispersion technique. The structures and thermal properties of prepared PU and PUA were analyzed and characterized with FT-IR, UV–Vis spectroscopy and DSC. The PUA hybrid samples had lower glass transition temperature of hard segment and higher decomposition temperatures than PU sample. Performances of the emulsion and film were studied by means of apparent viscidity, particle size and polydispersity, surface tension and mechanical properties. The results indicated that the particle sizes of the PUA dispersions were larger than those of the pure PU and the solvent resistance, mechanical properties of PUA films was improved compare with the unmodified polyurethane film. The film had the biggest hardness and the least water absorption when the BA/MMA mass ratio 5:5 modified PU. The obtained PUA have great potential application such as coatings, leather finishing, adhesives, sealants, plastic coatings and wood finishes.     

Novel Environmentally Friendly Copolymers Carboxymethyl Starch Grafted Poly(Lactic Acid)

Modified natural polymers have been gaining increasing scientific interest for many years. In this study carboxymethyl starch (CMS) was grafted with L(+)-lactic acid (LA) in different molar ratios CMS/LA (1/36, 1/22 and 1/12), resulting carboxymethyl starch-g-poly(lactic acid) (CMS-g-PLA) copolymers. The grafting reaction was carried out by solution polycondensation procedure in toluene and stannous 2-ethyl hexanoate Sn(Oct)₂ as catalyst was utilized. Poly(lactic acid) (PLA) was synthesized in the same conditions with the copolymers for comparative analyses of the physico-chemical and thermal properties. The copolymers and PLA were structurally and morphologically characterized by FT-IR, ¹H-NMR spectroscopy, WAXD and SEM analyses, taking CMS as reference. The molecular weight of the copolymers, CMS and PLA were determined, using a dynamic light scattering technique. The thermal behavior of the products was studied by DSC and TG-DTG analyses. The CMS-g-PLA graft copolymers exhibited lower Tg and thermal stability than pure CMS.     

顺丁烯二酸酐生产的环境友好技术

以正丁烷选择性氧化制顺丁烯二酸酐为例，按照氧化还原进行的烃类选择性氧化反应，采用将催化循环的不同步骤在空间或时间上分离的操作方法，可大幅度地提高反应的选择性，实现环境友好生产。重点介绍了循环流化床、人为非定固定床和膜反应器这3种新反应技术在顺丁烯二酸酐生产中的应用。     

环保型脲醛树脂胶粘剂的合成研究

介绍了聚乙烯醇(PVA)、三聚氰胺在脲醛树脂胶粘剂合成过程中所起的改性作用,研究了反应温度、反应体系pH、甲醛与尿素摩尔比、PVA和三聚氰胺用量对脲醛树脂胶粘剂性能的影响。试验结果表明,在反应温度为80℃、反应体系pH为5．0、甲醛与尿素摩尔比为1．5、PVA和三聚氰胺用量分别为尿素与甲醛溶液总质量的1．0％和5％的条件下,合成的脲醛树脂胶粘剂的剪切强度为2．99MPa,游离甲醛的质量分数由传统工艺生产产品的0．6％～0．8％降低至0．063％,耐沸水时间为108min,且贮存稳定性好,达到了HJBZ-1998国家环境标志产品技术要求。     

An Environmentally Friendly Process for Textile Wastewater Treatment with a Medium-Chain-Length Polyhydroxyalkanoate Film

Journal of Polymers and the Environment - In this study, a novel medium-chain-length polyhydroxyalkanoate (mcl-PHA) film containing 39.25 mol% 3-hydroxyhexadecanoic acid...     

Environmentally Friendly Oil-Modified Polyesters as Polymeric Plasticizers for Poly(vinyl chloride)

Oil-modified polyesters were synthesized to serve as polymeric plasticizers for PVC. A total of four polymeric plasticizers with different average molecular weights were prepared. Characterizations were done using Fourier-transformed infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and gel permeation chromatography. Some of the tests conducted on PVC films include thermal stability test using thermogravimetric analyser, determination of glass transition temperature (T_g), plasticizer migration and leaching resistance test, morphology study of plasticized PVC films using field emission scanning microscope, toxicity test, and tensile test. Owing to the plasticizing effect of the palm oil-based compound, T_g of the plasticized PVC has decreased to an average of 65 °C at 20 wt% loading. The polymeric plasticizer is also able to contribute positively to the thermal stability and mechanical properties of the PVC films. Some of the advantages of incorporating polymeric plasticizer with high molecular weight includes lower rate of leaching from plastic, and improved tensile strength and elongation at break. Besides, thermal stability of the plastic studied using Kissinger’s and Flynn–Wall–Ozawa’s approaches shows that PVC blended with high molecular weight oil-modified polyester is more thermally stable, evidenced by the increase in the activation energy of decomposition, E_d. Toxicity test using brine shrimp egg shows encouraging results, where the oil-based plasticizer is considerably less toxic compared to some of the commercial plasticizers.     

Preparation of Economically Viable and Environment Friendly Composites from Effluents of Aleuritic Acid Industry

The synthesis of aleuritic acid from shellac is associated with generation of huge quantity of waste whose disposal leads to clogging of the sewage system and contaminates the water bodies into which the drain leads. The shellac waste, which was collected from the factory site and Jute fiber has been used to form a sustainable, eco-efficient and economical composite. Characterization of the resin and composite was done by FTIR, TG, DSC and SEM. Mechanical properties of the composites like tensile strength and impact strength etc. were measured.     

Characterization of Environmentally Friendly Polymers by Inverse Gas Chromatography: I Amylopectin

Amylopectin, as a potato starch based polymer, with a molecular weight of six million gram/mol was characterized using the Inverse Gas Chromatography Method (IGC). DSC method was also used to measure the glass and melting temperatures. Both DSC and IGC agreed well on a T_g of 105°C and T_m of 160–166°C. Nineteen solutes (solvents) were injected onto a chromatographic column containing amylopectin. These solutes revealed the interaction of alkanes with AP, and the wettability and water intake of AP. Alkanes showed exothermic values of interaction parameters which were increased as the temperature increased and as the number of carbons in the alkane series decreased. Retention diagrams of these solutes in a temperature range of 80–200°C revealed two zones, crystalline and amorphous. T_g and T_m were measured using these zones which complimented the DSC values. The two zones were used to calculate the degree of crystallinity below the melting temperature which ranged from 85% at 104°C to 0% at 161°C. The dispersive component of the surface energy of amylopectin was measured using alkanes which ranged from 25.35 mJ/m² at 80°C to 8.47 mJ/m² at 200°C. This is attributed to the weak crystalline surface of AP at 80°C and when the surface melted at 160°C the surface energy decreased due to the thermal expansion of the surface.     

丙烯酸废水处理工程实例

采用气浮-动态微电解—水解酸化—接触氧化工艺,对无锡某化工总厂丙烯酸废水原工艺和设备进行了改造,经过调试运行,监测结果表明,进水COD为6 000～10 000 mg/L时,处理出水COD小于60 mg/L。出水达到太湖地区重点工业行业主要水污染物排放标准。     

Structure,Mechanical, Thermal and Fire Behavior Assessments of Environmentally Friendly Crude Glycerol-Based Rigid Polyisocyanurate Foams

In this work, rigid polyisocyanurate foams were prepared at partial substitution (0–70 wt%) of commercially available petrochemical polyol, with previously synthesized biopolyol based on crude glycerol and castor oil. Influence of the biopolyol content on morphology, chemical structure, static and dynamic mechanical properties, thermal insulation properties, thermal stability and flammability was investigated. Incorporation of 35 wt% of crude glycerol-based polyol had reduced average cell size by more than 30% and slightly increased closed cell content, simultaneously reducing thermal conductivity coefficient of foam by 12% and inhibiting their thermal aging. Applied modifications showed also positive impact on the mechanical performance of rigid foams. Increase of crosslink density resulted in enhancement of compressive strength by more than 100%. Incorporation of prepared biopolyol resulted in enhancement of thermal stability and changes in degradation pathway. Up to 35 wt% share of crude glycerol-based polyol, foams showed similar flammability as reference sample, which can be considered very beneficial from the environmental point of view.     

Evaluation of the Biodegradability of Polyvinyl Alcohol/Starch Blends: A Methodological Comparison of Environmentally Friendly Materials

Polyvinyl alcohol (PVA) and starch are both biodegradable polymers. These two polymers can be prepared as biodegradable plastics that are emerging as one of the environmental friendly materials available now. In this study, after reacting with sodium trimetaphosphate (STMP), modified corn starch was blended with PVA in different ratios by a barbender. Test samples were prepared for mechanical and thermal properties measurements. The surface roughness and morphology of fractured surface of the samples were observed by an atomic force microscopy (AFM) and scanning electron microscope (SEM) measurements. Aqueous degradation by enzyme, water absorption and biodegradability behavior were evaluated for the degradability. The biodegradability of these materials was followed by bio-reactivity kinetics models. Results showed that the addition of modified starch could enhance its water uptake. With an addition of 20 wt% of modified starch, the blend had a maximum weight loss during enzymatic degradation. It was found that the degradability was enhanced with the addition of the starch. Analyzing the results of the biodegradability based on the kinetic models, the growth rate of the microorganism was found to be increasing with the increase of the content of starch in the PVA/starch blends in the first order reaction fashion. In our biodegradability analysis, i.e., based on the China national standards (CNS) 14432 regulations, we estimated the decomposition behavior based on the mentioned first order reaction. We found that the PVA/starch blends would take 32.47, 16.20 and 12.47 years to degrade by 70% as their starch content 0, 20 and 40 wt%, respectively.     

含重金属的硫酸废水的治理

介绍了“石灰中和－精密微孔过滤”技术治理含重金属的硫酸废水的工艺流程和处理效果,着重介绍了高分子精密微孔过滤技术的特点,操作方法和运行数据。     

Physical Properties of Cured Self-green Epoxidized Natural Rubber with Amino Acid

Journal of Polymers and the Environment - The environmental-friendly and sustainable development is a top concern of rubber industry. Here we reported a green method to fabricate a class of...     

Process Optimization for the Preparation of Beta-cyhalothrin Microspheres by Using the Response Surface Methodology

Journal of Polymers and the Environment - Microcapsulses can effectively encapsulate, protect, and control the release of insecticides. In this study, emulsion–solvent evaporation method was...     

改性高岭土处理含酸性媒介染料的印染废水

用十六烷基三甲基溴化铵(CTMAB)改性的高岭土处理以水溶性酸性媒介染料为主的印染废水.实验结果表明,当CTMAB-高岭土加入量为0.6 g/L、用石灰乳控制废水pH为9.5～10.0、聚丙烯酰胺的加入量为2.0 mg/L时,废水的处理效果最佳,废水色度和COD去除率分别达到98.0%和92.0%以上,出水色度和COD达到了GB4287-92<纺织染整工业水污染物排放标准>一级排放标准.     

Synthesis and Characterization of Novel Biobased Ion-Exchange Bisfuran Polyamides Prepared by Interfacial Polycondensation of Bisfuran Diamine Monomer and Sustainable Dicarboxylic Acid Derivatives

Journal of Polymers and the Environment - Polymers based on the furanic compounds derived from renewable carbohydrates have seen massive growth due to their unique properties and increasing...     

电渗析法处理低浓度乙酸废液的研究

用电渗析法处理配制的乙酸质量分类为２．５％左右的乙酸水溶液,浓缩液乙酸质量分数达到２０％,稀相出水乙酸质量分数至０．０２％;对影响处理过程的因素进行了探讨。     

利用废酸液制备脱硫剂

以废酸液为原料制备脱硫剂，具有原料来源广、价廉、工艺简单等优点，所制备的脱硫剂 主要理化标能达到商品脱硫剂的水平，脱硫剂可以再生，转适宜的再生温度为２０－５０℃，再生后，脱硫剂的脱硫能力有所下降。     

Properties of Starch/PVA Blend Films Containing Citric Acid as Additive

Starch/polyvinyl alcohol (PVA) blend films were prepared successfully by using starch, polyvinyl alcohol (PVA), glycerol (GL) sorbitol (SO) and citric acid (CA) for the mixing process. The influence of mixing time, additional materials and drying temperature of films on the properties of the films was investigated. With increase in mixing time, the tensile strength (TS), elongation (%E), degree of swelling (DS) and solubility (S) of the film were equilibrated. The equilibrium for TS, %E, DS and S value was 20.12 MPa, 36.98%, 2.4 and 0.19, respectively. The mixing time of equilibrium was 50 min. TS, %E, DS and S of starch/PVA blend film were examined adding glycerol (GL), sorbitol (SO) and citric acid (CA) as additives. At all measurement results, except for DS, the film adding CA was better than GL or SO because hydrogen bonding at the presence of CA with hydroxyl group and carboxyl group increased the inter/intramolecular interaction between starch, PVA and additives. Citric acid improves the properties of starch/PVA blend film compared to glycerol and sobitol. When the film was dried at low temperature, the properties of the films were clearly improved because the hydrogen bonding was activated at low temperature.     

超临界水氧化处理高浓度丙烯酸废水

采用超临界水氧化（SCWO）技术在连续蒸发壁式反应器内处理高浓度丙烯酸废水。实验结果表明：SCWO能有效地处理丙烯酸废水,废水COD和TOC去除率分别达到99％左右,且反应时间短;反应温度、反应压力和氧化剂加入量的增加有利于COD和TOC去除率的提高。实验得出的废水处理最佳工艺条件：反应温度693K、反应压力24～26MPa、氧化剂加入量1．0～1．5倍。对反应器出口试样进行色谱-质谱联用分析结果表明,小分子醇、醚类以及CO2和CO是主要的液相产物和气相产物。针对腐蚀和盐沉积问题,提出了预防措施。