巯基-烯光聚合制备交联网络聚合物的研究进展

巯基-烯光聚合体系是近年来发展的一种制备交联网络聚合物的新方法。介绍了用于制备交联网络聚合物的多官能团硫醇和烯类单体的发展及研究现状,概括了巯基-烯光聚合体系的主要特点,综述了巯基-烯/杂化光聚合体系的研究进展以及巯基-烯光聚合体系在涂料、胶黏剂、生物材料和光学材料等领域的研究现状,同时展望了巯基-烯光聚合体系的应用前景。     

NOx removal efficiency and N2 selectivity during selective catalytic reduction processes over Al2O3 supported highly cross-linked polyethylene catalysts

The performance of a highly cross-linked polyethylene catalyst supported on alumina for low temperature selective catalytic reduction of NO_x by unburned hydrocarbons (HCs) existing in an exhaust gas was examined at different engine conditions with the addition of exhaust-gas recirculation. The HXPE catalyst was shown to exhibit good NO_x reduction activity at low temperatures (100–250 °C) where the only reductant was the unburned HC, which was already present in the exhaust flow. The maximum NO_x reduction of approximately 52% was achieved at a temperature of 150 °C. HXPE demonstrated very good selectivity toward N₂ in the majority of tested conditions (∼80%).     

交联琥珀酸酯木薯淀粉的黏度特性研究

以木薯淀粉为原料,琥珀酸酐为酯化剂,醋酸酐、己二酸混合酸酐为交联剂,制备交联琥珀酸酯淀粉。着重研究药品添加量、反应温度、反应pH值及反应时间对交联琥珀酸酯淀粉的Brabender峰值黏度和热糊黏度的影响。结果显示:琥珀酸酐的添加量与峰值黏度成正比,但热糊黏度先增加后降低;醋酸酐、己二酸混合酸酐的添加量与峰值黏度成反比,但热糊黏度先增加后降低;其它反应条件对淀粉的影响为峰值黏度和热糊黏度都是先增加后降低。最佳的反应条件为:琥珀酸酐质量分数4%,醋酸酐、己二酸混合酸酐质量分数1.0%,温度25~30℃,pH8.5~9.0,反应时间1 h。     

抗温抗盐交联聚合物的性能评价

采用AM和AMPS二元共聚物和交联剂为N,N’-亚甲基双丙烯酰胺,开展了以油井堵水为目的交联聚合物溶液体系研究。研究结果表明所合成的交联共聚物耐温抗盐性良好,在矿化度5 000 mg/L模拟地层水中吸水倍率为22倍左右,在90℃的高温下滚动老化48 h交联聚合物仍保持良好的弹性和韧性,老化后吸水性吸水倍率为86.52,吸水后其强度较好、富有弹性。     

浅谈220kV交联聚乙烯电缆绝缘收缩率

阐述了高压交联聚乙烯(XLPE)绝缘收缩的原因,以悬链式生产线为例列举降低220 kV XLPE绝缘收缩的相应技术措施,通过实际工艺验证220 kV XLPE绝缘收缩率能够达到不大于4%的指标。     

The Binding of Anionic Dyes by Cross-Linked Cationic Starches

Adsorption of anionic dyes on the cross-linked with epichlorohydrin starches containing quaternary ammonium groups (CCS) was investigated and compared with that of modified starches containing only quaternary ammonium groups (CS). The adsorption of anionic dyes on CS and CCS closely follows the Langmuir model of adsorption. The computed Langmuir saturation capacity Q _o increases with increasing degree of substitution (DS) of CS or CCS and has the value from 0.81 mol/kg to 3.22 mol/kg for CCS and from 0.88 mol/kg to 1.87 mol/kg for CS. The effectiveness of the cationic groups in dye binding was about 1 mol/equiv for CSS with DS from 0.47 to 0.62 and all the cationic groups had attached one anionic groups of the dye. Increasing DS of CS decreases the effectiveness of dye binding due to the increase in solubility of CS, and the soluble part of CS binds the dye as a typical soluble polyelectrolyte. CCS are more suitable than CS for the anionic dye adsorption from a textile dyeing solution. DS of CCS should be about 0.5–0.6. They adsorb the anionic dyes in few minutes and acts in the wide range of pH of the solutions. The Langmuir saturation capacity Q _o and the effectiveness of the cationic groups in dye binding increase with an increase of the adsorption temperature. The positive values of the enthalpy and entropy suggest that the adsorption is endothermic and during the adsorption of the anionic dye on CCS the randomness of the system increases.     

通信电源用电缆及其通信行业标准

本文重点解读通信电源用交联聚烯烃绝缘电缆通信行业标准的主要内容,介绍了交联聚烯烃绝缘的技术特点.评述了聚氯乙烯（PVC）绝缘电缆在环保和安全方面存在的不足.通过比较说明了交联聚烯烃绝缘电缆相对于PVC绝缘电缆和非交联的无卤低烟阻燃聚烯烃绝缘电缆所具有的优势.本文还介绍了低压电缆制造技术,特别是交联工艺路线、电缆料添加剂及电缆料配混技术进展等方面的内容,对未来通信电源用电缆的发展以及标准修改内容提出了建议.     

交联木薯淀粉的干法制备及其性能研究

为了提高交联淀粉的生产效率,以木薯淀粉为原料,三偏磷酸钠为交联剂,采用机械活化辅助干法制备了交联木薯淀粉。以沉降积为评价指标,考察了三偏磷酸钠用量、氢氧化钠用量、反应温度、反应时间、球磨介质堆体积、转速对交联反应的影响。在单因素实验基础上,采用正交试验优化了工艺条件,并对交联木薯淀粉的理化特性和结构进行了表征与分析。结果表明,干法制备交联木薯淀粉的最佳工艺条件为：三偏磷酸钠用量4%,氢氧化钠用量2.5%,反应温度40℃,反应时间60 min,转速380 r·min^-1,球磨介质堆体积500 mL,在此条件下制备的交联木薯淀粉沉降积为1.52 mL;FTIR、XRD、SEM进一步证实木薯淀粉发生了交联反应。随着木薯淀粉交联度的增大,木薯交联淀粉较原淀粉透光率、膨胀度、溶解度下降,凝沉性增强,更适应食品工业的发展。     

酶促交联罗非鱼肉重组工艺研究

在低温下,以罗非鱼碎肉为原料,酪蛋白酸钠与谷氨酰胺转氨酶为复配交联剂,以凝胶强度为重组鱼肉质构的分析指标,在单因素实验基础上运用响应面设计方法对酶促交联鱼肉重组工艺进行优化并初探其交联机理。结果发现:NaCl添加量2.3%、谷氨酰胺转氨酶添加量1.1%、酪蛋白酸钠添加量1.5%、最佳反应时间为0.5 h;经过验证,此条件下重组鱼肉制品的凝胶实际值是3409.5 g×mm与理论预测值3493.5 g×mm基本一致,且比重组前鱼碎肉的凝胶强度提高了1.6倍。同时,由SDS-PAGE凝胶电泳图可知谷氨酰胺转氨酶和酪蛋白酸钠复配交联剂主要作用在相对分子质量为200和40 KDa的蛋白质。     

交联羧甲基瓜尔胶的制备

以植物瓜尔胶为原料、环氧氯丙烷为交联剂、氯乙酸为羧甲基化试剂,制备了交联羧甲基瓜尔胶。研究了环氧氯丙烷的用量、氯乙酸的用量、氢氧化钠的用量及反应温度对产品取代度的影响;考查了产品糊的耐温性能,并用FT-IR对产品的结构进行了表征。实验结果表明:配料质量比瓜尔胶∶环氧氯丙烷∶氢氧化钠∶氯乙酸为1.00∶0.015∶0.45∶0.40,反应温度50℃时,产品的取代度达最高0.340。FT-IR分析结果表明,瓜尔胶分子中引入了羧甲基基团,交联羧甲基瓜尔胶成功制备。与原瓜尔胶糊相比,产品糊的耐温性能得到改善。