Pure and mixed gas permeation study of silica incorporated polyurethane-urea membrane modified by MOCA chain extender

Polyurethane-urea (PUU) nanocomposite membranes have been prepared using various loadings of silica (SiO₂) nanoparticles. A Novel PU was fabricated by a two-step bulk polymerization technique based on polycaprolactone (PCL), hexamethylene diisocyanate (HDI), and diamine chain extender, 4,4-methylenebis(2-chloroaniline) (MOCA). The FTIR spectra indicated that the extent of phase separation reduces with increasing SiO₂ content. The presence of crystal regions in the soft and hard segments was confirmed by DSC and XRD analyses. The obtained results illustrated a decrement in the gases' permeation in the presence of SiO₂ particles. By increasing the filler content up to 15 wt% and pressure of 8 bar, the gas permeation value of the CO₂, O₂, and N₂ decreased 36%, 54%, and 59%, respectively. However, the permselectivity of the CO₂/N₂ and O₂/N₂ increased considerably, 55% and 13% respectively. On the contrary, by raising the temperature, a dramatic augmentation in the permeability of all gases with a simultaneous reduction in the selectivity values of both gas pairs was revealed. Increasing the pressure led to a decrease in the permeability values of all membranes for O₂ and N₂, whereas the permeability for CO₂ increased with the pressure. Nevertheless, the selectivity values for the pair of gases increased (at a pressure of 10 bar, 1.66 and 1.17 times the neat PU for CO₂/N₂ and O₂/N₂, respectively). Furthermore, the permeability of the CO₂, O₂, and N₂ for the mixed gases was smaller than for pure ones at the same gas upstream pressure. Nonetheless, like the pure gas, the selectivity of both pair gases increased.     

MOCA的合成

以邻氯苯胺和多聚甲醛为反应原料制备MOCA.与以邻氯苯胺和甲醛水溶液为原料的传统工艺相比,用多聚甲醛代替甲醛水溶液,使多聚甲醛在酸催化下慢慢分解生成甲醛,可以保证与邻氯苯胺的反应在比较缓和的条件下进行,避免了大量树脂状物质的生成,提高了产品收率.通过正交试验考察了物料配比、反应时间及反应温度等因素对反应的影响,并确定了最佳的工艺条件为:多聚甲醛与邻氯苯胺摩尔比1:2,反应时间为3h,反应温度为80℃.最佳工艺条件下产品收率为90.3%.     

基于MOCA技术的网络测试和网络建设

主要介绍广州有线基于MOCA技术传输互动电视的试点建设情况,详细分析MOCA技术在网络测试中的实际情况,总结测试中出现的问题,并提供工程建设方案。     

二胺固化MDI型聚氨酯弹性体

采用聚四氢呋喃二醇（PTMG）和二苯基甲烷二异氰酸酯（MDI）合成预聚物,经3,3’-二氯-4,4’-二苯基甲烷二胺（MOCA）扩链合成了聚氨酯弹性体,测定了其物理性能和高温性能。结果表明,该体系弹性体具有良好的物理机械性能,尤其是其高温性能更加突出,120℃时撕裂强度保持率可达40％,用该体系制得的矿用磨盘,使用寿命是甲苯二异氰酸酯（TDI）体系的3倍以上,显示出良好的应用前景。     

E-300与MOCA扩链聚氨酯弹性体的力学性能比较

以聚酯(PEA、PEPA、PCL)或聚醚(PTMG、PPG、PO/PT)和TDI为原料合成聚氨酯(PU)预聚体,分别用MOCA和E-300作扩链剂制备聚氨酯弹性体。比较了这2种扩链剂对PU弹性体力学性能的影响。实验结果表明:MOCA-PU的硬度、模量和强度均大于E-300-PU,E-300-PU的扯断伸长率略高于MOCA-PU。在相同硬度下的聚醚型PU弹性体,E-300-PU比MOCA-PU的撕裂强度高。     

杂浆泵用聚氨酯护套的研制

介绍了泥浆泵护套用聚氨酯胶的配方和制作工艺，并对预聚物中－ＮＣＯ含量和ＭＯＣＡ用量进行了考察。     

新型聚天门冬氨酸酯的合成及其在弹性聚氨酯涂料中的应用

通过二乙烯三胺与马来酸二丁酯的Michael加成反应,合成了一种新型脂肪族多元仲胺-聚天门冬氨酸酯（DETA—PAEs）。对照研究了DETA—PAEs和3,3’-二氯-4,4’-二氨基二苯基甲烷（MOCA）作为弹性聚氨酯涂料固化剂在反应凝胶时间、涂层的拉伸强度、断裂伸长率以及耐黄变等性能方面的差异,证明DETA—PAEs的综合性能优于MOCA。     

双组分聚氨酯涂料的制备与性能表征

以聚酯型聚氨酯预聚物或聚醚型聚氨酯预聚物为甲组分,分别以环氧树脂,MO-CA,含羟基丙烯酸树脂,醇酸树脂为乙组分,制备出双组分聚氨酯涂料.研究了四种乙组分对两种聚氨酯涂膜的拉伸强度、断裂伸长率、热稳定性的影响.对于聚酯型聚氨酯,当-NCO/-OH为1∶1时涂膜性能最好;对于聚醚型聚氨酯,当-NCO/-OH为1.1∶1时,涂膜性能最好.在所选的四种乙组分中,以环氧树脂为乙组分时涂膜热稳定性最好,初始失重温度为297.7℃;以MOCA与聚酯型聚氨酯配合制得的涂膜具有良好的拉伸强度和断裂伸长率.固化时间对涂膜的力学性能也有一定的影响,发现涂膜力学性能随固化时间的延长而增加.     

Optimization of PGNAA set-up for the elements detection in aqueous solution

A prompt gamma neutron activation analysis(PGNAA)set-up was developed for the elements detection in aqueous solution,which includes a 241Am-Be neutron source and a 4-inch BGO detector.The geometry of set-up is determined by a series of simulations with the MOCA code to improve the efficiency of the elements detection.The thermal neutron flux and the gamma-ray self-absorption are considered during the optimization calculations.Experiments were performed to validate the set-up using samples including chlorine and mercury,respectively.The result shows that the characteristic peak count has linear relationship with the chlorine and mercury concentration changing.The minimum detectable concentrations of chlorine and mercury were found as 54 mg/L and 51.4 mg/L,respectively.     

全水固化聚氨酯防水涂料研究

介绍了一种能在潮湿基面上施工的全水固化双组分聚氨酯防水涂料的制作方法,阐述了其反应原理,讨论了主要原材料的作用及对产品性能的影响,尤其是加水量的控制.对全水固化和莫卡固化的聚氨酯防水涂料的性能进行对比,结果表明,完全可以用水代替莫卡作为聚氨酯防水涂料的固化剂.