基于纳米TiO2添加的新型航空涂料性能研究

目的解决纳米TiO_2在涂料中的团聚问题,同时实现增强涂层防腐蚀、疏水性能和耐紫外老化性能。方法以氯醚树脂为航空涂料的主要成膜物质,以经氟硅烷改性后的金红石型纳米TiO_2颗粒为主要吸光剂和疏水剂,配合其他合适填料和颜料制备一种新型航空涂料,通过拉拔法、硬度测试法、电化学极化曲线法、接触角测试法和人工紫外加速老化等测试手段分别对涂层的力学性能、电化学性能、疏水性能和耐紫外老化性能进行研究。结果改性后的金红石型纳米TiO_2颗粒的分散性及与氯醚树脂的相容性得到改善。当添加量为2%~3%时,涂层腐蚀防护性能、表面疏水性、耐紫外老化性能达到最佳,附着力、硬度等力学性能达到航空涂料的基本使用要求。结论该涂料有效地解决了纳米TiO_2在涂料中的团聚问题,提高了涂层的防腐蚀、疏水性能和耐紫外老化性能。     

稠油降解菌的筛选、鉴定与菌群构建

分别以烷烃、芳烃、胶质沥青质为唯一碳源,从稠油污染过的土壤里分离、筛选可培养的降解菌,将16株组合构建SL-16稠油降解菌群,通过室内摇瓶实验测得该菌群在最佳条件下对陈庄油田稠油降解率可达68%,其适宜的生长及降解温度为35～45℃,pH值为7.0～9.0,含盐量为4 000～14 000 mg/L,接种量为2%,稠油...     

短胶化、冲击好耐候粉末涂料用聚酯树脂的研究

介绍了偏苯三甲酸酐、三羟甲基丙烷等单体的用量对耐候聚酯树脂粉末涂料胶化时间的影响及l，6-己二醇、2-甲基-l，3-丙二醇等单体对提高耐候聚酯树脂粉末涂层低温抗冲击性能的作用。     

Using thermal analysis with kinetic calculation method to assess the thermal stability of azo compound on construction materials

The application of construction polymers in engineering and alternative materials has always occupied a place in the market. In the production process of polymer resins, initiators can be used to lower the polymerization reaction energy threshold, which can improve reaction efficiency and reduce energy loss. However, as a commonly used energetic substance in the polymerization process, azos have caused related process hazards due to their exothermic characteristics. Because of this, it is essential to examine and analyze the thermal hazard characteristics of emerging azo substances, such as 2-cyanopropan-2-imemicarbazide (CABN). Although previous literature performs the calculation on related thermal hazard parameters of CABN, there is still exists a void for discussion in estimating the reaction model to avoid analogous hazards and enhance the existing thermal analysis. Based on the past literature, the reaction model is improved with thermogravimetric analysis as evidence. The revised thermal hazard parameters are calculated as the basis of control and mitigation measures, the kinetic model is used to estimate the modified safety parameters, and in the judgment of the runaway reaction, the critical temperature of the runaway is found by analyzing the influence of slight changes in ambient temperature on the reaction temperature. The results show that the critical temperature that causes CABN to enter the runaway reaction is delayed, and the hazard is lower than in the storage situation. Therefore, the thermal hazard to CABN mainly focuses on the safety environment and measures during storage.     

Assessment of bisphenol A released from reusable plastic, aluminium and stainless steel water bottles

Bisphenol A (BPA) is a ubiquitous high volume industrial chemical that is an estrogen and an environmental endocrine disrupting chemical. Bisphenol A is used extensively in the production of consumer goods, polycarbonate plastics, epoxy resins and coatings used to line metallic food and beverage cans. There is great concern regarding the possible harmful effects from exposures that result from BPA leaching into foods and beverages from packaging or storage containers. The objective of this study was to independently assess whether BPA contamination of water was occurring from different types of reusable drinking bottles marketed as alternatives to BPA-containing polycarbonate plastics. Using a sensitive and quantitative BPA-specific competitive enzyme-linked immunosorbent assay we evaluated whether BPA migrated into water stored in polycarbonate or copolyester plastic bottles, and different lined or unlined metallic reusable water bottles. At room temperature the concentration of BPA migrating from polycarbonate bottles ranged from 0.2 to 0.3 mg L⁻¹. Under identical conditions BPA migration from aluminium bottles lined with epoxy-based resins was variable depending on manufacturer ranging from 0.08 to 1.9 mg L⁻¹. Boiling water significantly increased migration of BPA from the epoxy lined bottles. No detectable BPA contamination was observed in water stored in bottles made from Tritan™ copolyester plastic, uncoated stainless steel, or aluminium lined with EcoCare™. The results from this study demonstrate that when used according to manufacturers’ recommendations reusable water bottles constructed from “BPA-free” alternative materials are suitable for consumption of beverages free of BPA contamination.     

Time course of isocyanate emission from curing polyurethane adhesives

The time course of isocyanate emission from curing polyurethane (PUR) resins and adhesives was studied in two different emission test chambers. The measured emissions were strongly dependent on the type of experiment. The adhesives under investigation contained different types of diisocyanates and are used for different applications, e.g. for fixing of textile floor coverings. The influence of the curing mechanism on emission was studied by comparing the emission curves of one-component adhesives (OCA) and two-component adhesives (TCA). For TCA, the decrease in isocyanate emission was found to follow a two-step process during curing. In the first step, the emission is dominated by surface evaporation, and the decay of emission is mainly caused by the decrease in monomer content due to reaction. In the second step, the release is limited by internal diffusion. The influence of monomer reactivity on the emission profile could be demonstrated for 2,4′- and 4,4′-MDI. The less-reactive 2,4′-MDI caused prolonged emission. A strong dependence of emission rates on temperature and adhesive viscosity was also obvious. The evaluation of emission rates of different commercially available PUR adhesives showed the highest emission from systems that are applied at high temperatures. The high reactivity of diisocyanates requires special techniques for sampling and analysis. Therefore, an analytical method using HPLC–MS/MS was developed that enables limits of quantitation of <5 ng/m³ with a sampling volume of 100 l.     

Quaternized agricultural by-products as anion exchange resins

The objectives of this study were the chemical modification of readily available, low-cost agricultural by-products to anion exchange resins and the selection of the best modified by-product for further use in anion removal. Resins were prepared through the quaternization of a series of 12 agricultural by-products with N-(3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHMAC). Phosphate ion adsorption assays were conducted at pH 7 in order to compare adsorption properties among the by-products. Quaternized corn stover showed the highest phosphorus adsorption at 0.66 mmole/g. Since corn stover exhibited the best uptake of phosphate ion, it was compared to a commercially available, cellulose-based anion exchange resin. Additionally, adsorption capacities of quaternized corn stover for arsenate, chromate, and selenate were evaluated and adsorption efficiencies were determined in simulated wastewater samples. Our results indicate that modified corn stover demonstrates good adsorption uptake for arsenate and selenate and especially for chromate.     

大孔网状树脂在富集水体中有机物的应用

介绍了ＸＡＤ及ＧＤＸ型大孔网状树脂富集水体中痕量有机物的方法。讨论了上述树脂对某些有机物的富集率；影响树脂对有机污染物富集率的因素，如洗脱剂的种类，水样流速，水样和洗脱液保存时间及有机物性质等因素的影响。提出了富集过程中应注意的问题。     

离子交换树脂对高浓度氨氮废水的吸附研究

采用D707、D708两种不同类型的离子交换树脂对高浓度氨氮废水进行吸附处理研究,分析了不同的吸附条件及等温吸附模型对吸附效果的影响.静态吸附实验表明:NH+4的吸附率随树脂投加量的增大而增加,在非碱性条件下树脂对NH+4的吸附率随p H的升高而增加;恒速振荡时间达到90 min以上时两种树脂可吸附平衡,当p H为7时,D707、D708树脂对NH+4的吸附容量分别达到196.1、217.4 mg·g-1;D707、D708树脂对NH+4的吸附属吸热过程,随温度的升高树脂对NH+4的吸附率逐渐增大,在298 K温度下D707、D708树脂吸附NH+4的表观吸附活化能Ea分别为54.67和34.46 k J·mol-1,吸附过程为液膜扩散主控制;树脂对NH+4吸附符合Langmuir吸附等温式;使用2 mol·L-1H2SO4对树脂进行解吸,脱附率达到98%以上,重复实验3次吸附率基本不变.     

GDX-502对一元酚动态吸附曲线和吸附容量的研究

测定了GDX-502树脂对水中9种一元酚的动态吸附曲线和吸附容量,讨论了可能的吸附机理?实验结果表明,水中各种酚对GDX-502存在着竞争吸附,若水样体积足够大,则水也参与竞争吸附?浓度高的酚,竞争能力强,被吸附容量大?相同浓度的酚,溶解度越小,偶极矩适当大,并能做为电子受体与树脂形成较强的π-键合作用力,则竞争占优势,被吸附容量大?动态吸附曲线上负吸附现象的存在是竞争吸附,特别是水处于优势吸附时的结果