Reactive surfactants in heterophase polymerization. XVII. Influence of the surfactant on the mechanical properties and hydration of the films

In the context of a European union‐supported network on “Reactive Surfactants for Heterophase Polymerization,” different polymerizable surfactants (surfmers) have been synthesized and engaged in the emulsion polymerization of styrene, butyl acrylate, and acrylic acid. The thermomechanical properties of films cast from these different latices are reported in this article. The evolution of the mechanical properties with temperature and the effect of water molecules on these properties are studied. We observed that the studied surfactants do not influence the properties of the dry films. However, some differences due to grafting of reactive surfactants appeared when the films were wet. The amount of water uptake is drastically decreased when only reactive surfactants are present in the film. Concerning the mechanical behavior of the wet films, a decrease of the plastic flow stress is observed for all the samples whatever the nature of the surfactant (reactive or conventional). Hence, calorimetric measurements and dynamic mechanical analysis are used to identify the possible mechanisms that induce the change in the mechanical behavior of the latex films. In the case of reactive surfactant grafted to the polymer, the very low value of water uptake is accompanied by a plasticization of the polymer. In contrast, no plasticizing effect is observed in the case of nonreactive surfactant, even if the amount of water is very large. Finally, the tensile behavior of the styrene–butyl acrylate copolymer versus temperature is analyzed in the frame of the quasi point defects (qpd) model. Both rubber elasticity and chain orientation effects are taken into account to describe the behavior laws at large extensions (i.e., ? ≈ 1.2). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1686–1700, 2002; DOI 10.1002/app.10548     

淮河流域水资源短缺风险评估与时空分析

根据2003-2013年淮河流域五省的降水量、径流系数、人均水资源量、人均GDP、人口密度等相关数据,构建水资源短缺风险评价体系,用熵权法对指标赋值,运用可变模糊模型对淮河流域及各省的水资源短缺风险进行评估和时空差异分析。结果表明:2003-2013年间淮河流域水资源短缺风险值总体较高,且呈缓慢的增长趋势,2004年降水较少,风险值达到最高;十年间河南省风险增加最为明显,而山东省较为稳定,风险增加也最低;在淮河流域五个区域中,河南省的风险程度最高,达到3.52;江苏省、山东省次之;安徽省和湖北省相对较低,达到2.86和2.51。水资源短缺风险二级指标分析发现,危险性最强的是河南省,安徽省最小;水资源短缺易损性最强的是山东省,湖北省最小;水资源短缺暴露性最强的是江苏省,山东省最小;水资源短缺可恢复性最好的是湖北省,河南省最差。同时,所有评价指标中人口密度、人均GDP、降水量对水资源短缺风险的影响较大。     

利用南水北调工程改善济宁水生态环境的措施

通过对济宁市防治水污染技术研究, 提出水污染防治在政策措施上实施治污抓源头, 杜绝不达标排放; 在城市 建设规划上, 把河湖生态湿地建设、 改善居住生活环境与城市建设有机结合; 在河湖治理上, 坚持工程、 生物措施并 举; 在工程管护上, 坚持依法治水。利用南水北调东线工程建设, 实施水污染防治建设, 通过对济宁市水污染防治成 果的阐释, 为今后水污染治理提供成功的经验和做法。     

水资源适应性利用理论及其在治水实践中的应用前景

水系统受气候变化和人类活动的影响,一直在不断地变化,因此水资源的开发利用也应适应这种变化,而不能按照固定的控制阈值或约束条件来进行。当然,也不是被动的、随意的去适应。在对水系统及其与环境变化关系剖析的基础上,分析了水资源适应性利用的原理与模式;基于对环境变化下水资源适应性利用机理的认识,提出水资源适应性利用理论的框架体系,阐述了其基本理念和关键内容;基于对我国现代治水实践的分析,分析了其暗含的水资源适应性利用理论的内容,以及我国治水实践中存在的问题及应用水资源适应性利用理论解决这些问题的可能途径。研究认为,水资源适应性利用理论对水资源合理开发、综合利用、科学管理具有重要的指导作用,为环境变化下水资源利用研究与实践奠定理论基础。     

基于非负矩阵分解的水量分配方案后评价

提出了水量分配方案后评价指标体系,建立了基于非负矩阵分解的水量分配方案后评价模型,并以1983年国务院批复的引滦水量分配方案为研究对象进行了水量分配方案诊断式后评价。该方法利用非负矩阵分解算法将指标矩阵最大程度分解为基向量和权向量,根据权向量元素的数值对水量分配方案进行评级,根据基向量元素的数值判断评价指标的实施状况。通过对引滦水量分配方案质量、实施过程、实施效果和可持续性的调查分析,得出方案综合后评价结果为优,但在来用水可持续性、对水环境影响及水质目标保证率等方面需加以改进。评价结果表明,基于非负矩阵分解原理的后评价方法评价效果较好,可为水量分配方案等项目的后评价提供科学依据。     

含碘高氯乳剂的制备和性能研究

碘离子掺入到高氯乳剂可以显著提高其感光性能。碘离子掺入到亚表层可增加乳剂的光吸收,提高感光度,增加反差。最佳掺入量为0.6％mol/mol Ag,掺入位置在65％Ag处,KI加入速度约8s。在一定范围内(小于1.5％mol/mol Ag)碘离子掺入亚表层对清晰度没有明显影响。如果铱掺杂的掺杂位置为亚表层,掺杂量为10~(-7)mol/mol Ag,铱络合物可有效地改善含碘高氯乳剂的高照度互易律失效。     

Application of enzymatically gelled chitosan solutions to water‐resistant adhesives

An investigation was undertaken on the application of dilute chitosan solutions gelled by tyrosinase‐catalyzed reaction with 3,4‐dihydroxyphenethylamine (dopamine). The tyrosinase‐catalyzed reaction with dopamine conferred water‐resistant adhesive properties to the semidilute chitosan solutions. The viscosity of the chitosan solutions increased highly by the tyrosinase‐catalyzed reaction and the subsequent reactions between o‐quinone compounds and chitosan. These highly viscous, gel‐like modified chitosan materials were allowed to spread onto the surfaces of the glass slides, which were tightly lapped together and held them in water. Tensile shear adhesive strength of over 400 kPa was observed for the modified chitosan samples. The increase in the amino group concentration of the chitosan solutions and the molecular mass of the chitosan used effectively led to the increase in adhesive strength of the glass slides. In addition, in the case where the chitosan solution was gelled by the enzymatic reaction with dopamine in the presence of poly(ethylene glycol), adhesive strength sharply increased at shorter reaction times concomitantly with the increase in the viscosity of the chitosan solutions because the tyrosinase activity effectively was retained by poly(ethylene glycol). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1818–1827, 2007     

羧基化高纯单壁碳纳米管修饰电极对乙酰甲喹的高灵敏检测

采用羧基化高纯单壁碳纳米管(c SWCNTs)固载于金电极表面来构筑乙酰甲喹电化学传感器。运用循环伏安法(CV)、差分脉冲伏安法(DPV)和电化学交流阻抗法(EIS)测定传感器的性能。结果显示,该传感器对乙酰甲喹的电化学还原具有显著的催化性能,修饰电极的峰电流达到-128.40μA,是裸电极峰电流的1167倍。通过对传感器性能影响因素的考察,得到最优制备条件为cSWCNTs涂覆量为4μL(质量分数0.10%分散液),搅拌速度1000 r/min,pH=7.0的PBS浓度为0.2 mol/L,-0.5V电压下富集30 min。在该条件下制备的传感器峰电流与乙酰甲喹在1～500nmol/L范围内呈良好的线性关系,相关系数为0.998,方法的检出限为0.76nmol/L。该传感器被成功地应用于实际样品检测,加标回收率在81.7%～124.0%。     

两种聚氨酯防水涂料的比较

对焦油型和非焦油水固化型聚氨酯防水涂料B组分的生产工艺、配方特点，施工操作工艺、固化时间、涂膜性能等方面进行了比较，指出新开发的非焦油型聚氨酯涂料生产周期短、能耗少、气味小，是环保型聚氨酯防水涂料。     

Application of CO2 laser heating zone drawing and zone annealing to nylon 6 fibers

Nlon 6 fibers were zone drawn and zone annealed by using a continuous wave carbon dioxide laser to develop their mechanical properties. A laser‐heating zone drawing was carried out under a applied tension of 35.4 MPa at a power density of 9.65 W · cm^?2, and then the zone‐drawn fiber was annealed. A laser‐heating zone annealing was carried out in two steps at a power density of 9.65 W · cm^?2; the first step was carried out under 423 MPa and the second under 517 MPa. The treating temperature of the fiber heated by the CO₂ laser was measured by using an infrared thermographic camera equipped with a magnifying lens. The treating temperature at the zone drawing is 138°C, and those at the first and the second zone annealing are 121 and 125°C, respectively. The second laser‐heated zone‐annealed fiber has a birefringence of 65.2 × 10^?3, a degree of crystallinity of 54%, and a storage modulus of 21 GPa at 25°C. Wide‐angle X‐ray diffraction patterns for the laser‐heated zone‐drawn and the zone‐annealed fibers show (200) reflection and (002/202) doublet due to only an α form on the equator. The laser‐heated zone‐drawn fiber has a melting endotherm peaking at 216°C and a trace of shoulder on the higher temperature side of its peak, and the laser‐heated zone‐annealed fibers have a single melting endotherm peaking at 216°C. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1711–1716, 2002