Pervaporation of 50 wt % ethanol–water mixtures with poly(1‐trimethylsilyl‐1‐propyne) membranes at high temperatures

Poly(1‐trimethylsilyl‐1‐propyne) (PTMSP) membranes have been used to separate ethanol–water mixtures by pervaporation. This polyacetylene is known to present high affinity toward ethanol, showing high selectivity and ethanol permeation flux. The performance of this polymer in the separation of alcohol–water solutions has been evaluated over long periods (572 h) at a high temperature (75°C) to examine the deterioration of the transport properties in the separation of 50 wt % ethanol–water solutions. Although PTMSP membranes present good characteristics for the separation of gases and liquid mixtures, their organic selectivity decrease with the operating time because of the relaxation processes of the polymeric chains, which affect the free volume of the polymer, the deterioration being more evident for concentrated solutions. The effects of the operation temperature on the characteristic parameters of pervaporation have also been studied to establish how this variable affects the performance of PTMSP membranes. The selectivity increases slightly with the operation temperature, but the effect of the temperature on the separation factor decreases as membranes are degraded with the operation time. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2843–2848, 2007     

Synthesis,degradation, and drug delivery of cycloaliphatic poly(ester anhydride)s

The high melting point of poly(1,4‐cyclohexanedicarboxylic anhydride) [poly(CHDA)] is a disadvantage, in that it is intractable in the melting process of a drug delivery system. This report relates to diols introduced into the polyanhydride main chain to decrease its melting point. Various poly(ester anhydride)s containing ethylene glycol, 1,3‐propanediol, 1,4‐butanediol, or 1,6‐hexandiol [poly(CHDA–XDO)] were synthesized by the esterification reaction and melt polycondensation. FTIR, DSC, WAXD, and intrinsic viscosity of polymers were recorded and hydrolytic degradation, as well as in vitro drug delivery, was conducted. The results show that the samples are stable in an anhydrous environment at room temperature and degrade in water following a surface erosion mechanism. The degradation period of poly(CHDA–XDO) ranged from 130 to 320 h as a result of the different diols and amounts of XDO introduced. The in vitro drug delivery gave 130–350 h of stable delivery along with the typical surface erosion mechanism. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2509–2514, 2002     

四唑嘧磺隆水分散粒剂在稻田环境中的残留动态

为评价除草剂四唑嘧磺隆在水稻上使用后的残留动态及环境安全性，在北京海淀区进行了50％四唑嘧磺隆水分散粒剂在水稻上的残留动态和最终残留试验研究。样品经丙酮提取抽滤后，再经液液分配及氧化铝柱净化、浓缩、定容后，用紫外检测器的液相色谱进行测定。其有效成分四唑嘧磺隆的最低检出量为0．02ng，在稻田水、土壤、鲜植株、稻壳、糙米样品中的平均回收率为82．4％-105．0％，变异系数为1．1％～14．1％，符合农药残留分析的要求。结果表明：四唑嘧磺隆在水稻植株上的半衰期为2．4d，在土壤巾的半衰期为5．5d，在稻田水中的半衰期为1．9d，施药后7d四唑嘧磺隆在水稻植株上的消解达到80％以上。50％四唑嘧磺隆水分散粒剂按80、120g／hm。使用，施药1次，收获时，四唑嘧磺降在糙米、稻壳、稻草、土壤中的残留量均未检出。     

Poly(L‐lactide). X. Enhanced surface hydrophilicity and chain‐scission mechanisms of poly(L‐lactide) film in enzymatic,alkaline, and phosphate‐buffered solutions

Attempts were carried out to enhance the surface hydrophilicity of poly(L ‐lactide), that is, poly(L ‐lactic acid) (PLLA) film, utilizing enzymatic, alkaline, and autocatalytic hydrolyses in a proteinase K/Tris–HCL buffered solution system (37°C), in a 0.01N NaOH solution (37°C), and in a phosphate‐buffered solution (100°C), respectively. Moreover, its chain‐scission mechanisms in these different media were studied. The advancing contact‐angle (θ_a) value of the amorphous‐made PLLA film decreased monotonically with the hydrolysis time from 100° to 75° and 80° without a significant molecular weight decrease, when enzymatic and alkaline hydrolyses were continued for 60 min and 8 h, respectively. In contrast, a negligible change in the θ_a value was observed for the PLLA films even after the autocatalytic hydrolysis was continured for 16 h, when their bulk M_n decreased from 1.2 × 10⁵ to 2.2 × 10⁴ g mol^?1 or the number of hydrophilic terminal groups per unit weight increased from 1.7 × 10^?5 to 9.1 × 10^?5 mol g^?1. These findings, together with the result of gravimetry, revealed that the enzymatic and alkaline hydrolyses are powerful enough to enhance the practical surface hydrophilicity of the PLLA films because of their surface‐erosion mechanisms and that its practical surface hydrophilicity is controllable by varying the hydrolysis time. Moreover, autocatalytic hydrolysis is inappropriate to enhance the surface hydrophilicity, because of its bulk‐erosion mechanism. Alkaline hydrolysis is the best to enhance the hydrophilicity of the PLLA films without hydrolysis of the film cores, while the enzymatic hydrolysis is appropriate and inappropriate to enhance the surface hydrophilicity of bulky and thin PLLA materials, respectively, because a significant weight loss occurs before saturation of θ_a value. The changes in the weight loss and θ_a values during hydrolysis showed that exo chain scission as well as endo chain scission occurs in the presence of proteinase K, while in the alkaline and phosphate‐buffered solutions, hydrolysis proceeds via endo chain scission. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1628–1633, 2003     

N,N,N-三甲基-2,3-二(硬脂酰氧基)丙基氯化铵(CDESA)的生物降解性

采用活性环氧中间体失水甘油基三甲基氯化铵合成了一种阳离子双酯表面活性剂——N,N,N-三甲基-2,3-二(硬脂酰氧基)丙基氯化铵(CDESA),来代替传统的难降解的表面活性剂型柔软剂,如目前国内仍在大量使用的双十八烷基二甲基氯化铵(D1821)。对CDESA的好氧降解性能进行了研究:以天然环境中的生活沉降污泥作为微生物源,用河水稀释,经培养、驯化后用于测试降解时间和半衰期,并与D1821的好氧降解性能作了对比。结果表明,CDESA的半衰期为3 d,容易降解,而D1821半衰期为7 d,较难降解,CDESA生物降解性能优于D1821。     

MOFs复合材料催化降解水中有机污染物的应用研究进展

金属有机框架材料（MOFs）具有比表面积较高、孔径尺寸可调、结构可设计和可以功能化的特点，近年来受到广泛关注，尤其是基于MOFs的复合材料在催化降解水中有机污染物的作用越来越突出，这是近年来MOFs的一个重要研究方向。本文综述了MOFs复合材料在催化降解水中有机污染物领域的研究情况；介绍了MOFs及其特性；说明了MOFs复合材料的负载方式；总结了MOFs复合材料在催化降解水中有机污染物方面的应用。同时，阐述了MOFs复合材料催化降解水中有机污染物的机理及其存在的问题。最后，提出未来MOFs复合材料在催化降解水中有机污染物的研究方向是合成形貌多样、结晶性能好的新型高稳定性材料以及开发新的MOFs及其复合材料的制备方法。     

SnO2和SiO2用于PVC的阻燃消烟及协同作用

研究了二氧化锡和二氧化硅对软PVC阻燃消烟性的影响。通过对极限氧指数、剩炭率、烟密度的测定和DTATG曲线的分析证明,添加8g二氧化锡/二氧化硅复合阻燃剂的PVC的氧指数和剩炭率比未添加的分别增高5.5个单位和4.1%,烟密度降低16.4%,降解活化能分别降低38kJ/mol和23.1kJ/mol,从而证明二氧化锡/二氧化硅复合阻燃剂对于PVC是一种很好的阻燃消烟剂,二氧化锡和二氧化硅有很好的协同作用。同时证明这种复合阻燃剂能代替三氧化二锑,使产品的成本进一步降低。     

碳酸钙对乙烯-丙烯酸丁酯共聚物阻燃与力学性能及热降解行为影响研究

采用极限氧指数法、热重分析和差示扫描量热分析等研究了碳酸钙（CaCO3）对乙烯-丙烯酸丁酯共聚物（EBA）阻燃及热降解行为的影响，探讨了CaCO3对EBA力学性能和熔体流动速率的影响。结果表明，CaCO3降低了EBA的拉伸强度、断裂伸长率和熔体流动速率，但复合阻燃材料仍具有良好的加工性能；当CaoCO3含量为60％（质量分数，下同）时，阻燃材料的极限氧指数可达28．5％。CaCO3通过EBA在热降解过程中与之发生化学反应来改变EBA的热降解行为，提高在高温下的热稳定性，降低EBA的热降解速率，促进高温下成炭在凝缩相中发挥阻燃作用。此外，CaCO3与EBA在热降解过程中形成隔热、隔氧的多孔泡沫膨胀结构，可进一步加强阻燃效果。     

Degradation of Leaf Litter Phenolics by Aquatic and Terrestrial Isopods

To investigate species-specific decomposition rates of litter from native (Quercus faginea) and introduced (Eucalyptus globulus) tree species in Portugal, we monitored changes in the phenolic signature of leaf litter during decomposition as mediated by an aquatic, Proasellus coxalis (Isopoda: Asellota), and two terrestrial, Porcellio dispar and Eluma caelatum (Isopoda: Oniscidea), detritivores. Although the litter of Eucalyptus and Quercus did not differ in overall protein precipitation capacity, we detected differences in terms of contents of particular phenolic compounds and phenol oxidation products. Accordingly, we observed food-specific consumption rates in Proasellus, but not in the terrestrial isopods. Proasellus digested Eucalyptus at significantly higher rates than Quercus, whereas the opposite was the case for Eluma, and Porcellio digested both litter types equally well. Despite slight differences in detail, effects of Proasellus on changes in the signature of litter phenolics were similar for both litter types, whereas terrestrial isopods—Porcellio and Eluma, although they differed from each other—digestively degraded phenolic compounds in Eucalyptus and Quercus litter, respectively, in different ways. Overall, however, degradation of litter phenolics was similarly effective on both litter types. From these data, we conclude that decomposition of Eucalyptus litter does not proceed more slowly than of litter from native Portuguese trees.     

Synthesis and characterization of novel copolymers with acid‐labile ketal moieties derived from camphor

Novel diastereomeric acrylic ketal monomers derived from (+)‐camphor and (±)‐camphor were synthesized. To investigate the applications of the camphor derivatives on positive‐tone photoresists, the acrylic ketal monomers were copolymerized with methyl methacrylate, methacrylic acid, and n‐butyl methacrylate. The optical activities of the chiral monomers and polymers were all evaluated. After UV irradiation and postexposure baking, the optical activity of the polymers decreased because of the decomposition of the acid‐labile pendant chiral groups. The existence of alicyclic camphyl groups increased the etching resistance of the photoresists. The thermogravimetric properties of the copolymers, the exposure curves, the lithographic evaluation of the positive‐tone photoresists, and the effects of alicyclic groups on the plasma etching resistance of the copolymers were all investigated. A resolution of a line‐and‐space pattern of 0.3 μm was achieved. Acid‐catalyzed dehydration crosslinking was also found in this system. Sufficient UV irradiation and heat treatment could cause the acid‐catalyzed dehydration crosslinking of pendant carboxyl groups and thereby increase the efficiency of the thermal resistance of the polymers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2969–2978, 2003