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83.
THERMODYNAMIC STUDY OF ADSORPTION OF PHENOLIC COMPOUNDS FROM AQUEOUS SOLUTION BY A WATER-COMPATIBLE HYPERCROSSLINKED POLYMERIC ADSORBENT 总被引:2,自引:0,他引:2
Ai-minLi Hai-suoWu Quan-xingZhang Gen-chengZhang ChaoLong Zheng-haoFei Fu-qiangLiu Jin-longChen 《高分子科学》2004,(3):259-267
Equilibrium data for the adsorption of phenolic compounds, i.e., phenol, p-cresol, p-chlorophenol and p-nitrophenol from aqueous solutions by a water-compatible hypercrosslinked polymeric adsorbent (NJ-8) within temperature range of 283-323 K were obtained and correlated with a Freundlich-type of isotherm equation, so that equilibrium constants KF and n were obtained. The capacities of equilibrium adsorption for all the four phenolic compounds on the NJ-8 from aqueous solutions are around 2 times as high as those of Amberlite XAD-4, which may be attributed to the unusual micropore structure and the partial polarity on the network. The values of the enthalpy (always negative) are indicative of an exothermic process, which manifests the adsorption of all the four phenolic compounds on the two polymeric adsorbents to be a process of physical adsorption. The negative values of free energy change show that the solute is more concentrated on the adsorbent than in the bulk solution. The absolute free energy values of adsorption for NJ-8 are always higher than those for Amberlite XAD-4, which indicates that phenolic compounds are preferentially adsorbed on NJ-8. The negative values of the adsorption entropy are consistent with the restricted mobilities of adsorbed molecules of phenolic compounds as compared with the molecules in solution. The adsorption entropy values of phenolic compounds for NJ-8 are lower than those for Amberlite XAD-4, which means the micropores of NJ-8 require more orderly arranged adsorbate. 相似文献
84.
反应注射成型聚氨酯互穿聚合物网络研究——刚性网络对于体系形态及性能的影响 总被引:1,自引:0,他引:1
用微型反应注射成型机制备了以聚氨酯(PU)为弹性相的两类同步互穿聚合物网络(SIN),其刚性相分别采用保留仲羟基的乙烯基酯树脂(VERH)以及封闭仲羟基的乙烯基酯树脂(VERA)。用傅里叶变换红外光谱在线跟踪了这类互穿网络的生成过程,发现刚性网络抑制了PU网络中硬段有序结构的形成,两个网络间有一定程度的互穿,而两个网络间的化学键作用进一步削弱氢键强度。自旋—自旋弛豫时间的测定进一步表明网络间存在一定的互穿以及刚性相对于PU硬段结晶的抑制作用。材料的力学性能与其SIN的形态有关。VERA网络对PU表现出明显的增强作用,而由VERH网络形成的SIN则由于体系相分离进程受到严重阻碍而使材料性能恶化。 相似文献
85.
研究了D160大孔吸附树脂对染料木黄酮的吸附性能.结果表明,在pH4.00时,该树脂对染料木黄酮有较好的吸附性能;静态饱和吸附容量为64.5mg/g树脂;用95%乙醇溶液作解吸剂,二次累计解吸率接近100%;表现速率常数k298=1.01×10-4s-1;测得吸附热力学参数分别为:△H=32.2kJ/mol,△S=119J/(mol·K),△G288=-2.03kJ/mol,△G298=-3.22kJ/mol,△G308=4.41kJ/mol.等温吸附服从Freundlich和Langmuir等温吸附规律;研究还表明,提高振荡频率对吸附有利. 相似文献
86.
Li Yan Liang Shao Ping Ren Yi Quan Zheng Man Geng Lu Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou China Key Laboratory of Polymer Materials for Electronics Guangdong China Graduate School of the Chinese Academy of Sciences Beijing China 《中国化学快报》2007,18(2):225-228
A series of novel liquid crystalline epoxides with lateral substituents were cured with anhydrides and the cure kinetics was investigated by non-isothermal DSC technique. The results showed that the lengths of lateral substituents have great effect on the value of Ea. The curing reaction became less active, when the liquid crystalline epoxides have long lateral substituents and were controlled by diffusion at the late stage of cure. A nematic structure was observed by POM and XRD. 相似文献
87.
几种树脂对西红花糖苷的吸附性能的研究 总被引:3,自引:0,他引:3
本文系统研究了硅胶和几种国产吸附树脂对西红花提取物溶液的吸附与洗脱性能,包括树脂的筛选,洗脱剂的选择,并研究了pH,温度和西红花提取物的浓度对西红花提取在SZ-1吸附树脂上的吸附影响,结果表明,SZ-1吸附树脂对西红花提取物的吸附能力较强,洗脱能力为最好,其吸附性能和洗脱性能均优于常用色谱固定相硅胶,SZ-1吸附树脂的静态吸附容量为1.04g/g,动态吸附容量为0.5-0.6g/g,洗脱率可达98%以上,且吸附速度快,易于洗脱和再生。 相似文献
88.
金橙G螯合形成树脂分离富集地质样品中的微量贵金属 总被引:10,自引:0,他引:10
主要研究了金橙G螯合形成树脂分离富集地质样品中金、铂、钯的最佳实验条件。在柱高大于16cm,0.1mol/L HCl介质的样品溶液以小于或等于0.5mL/min流速过柱,用0.1mol/L HCl的3%硫脲溶液以小于或等于0.5mL/min流速洗脱金、铂、钯(和铑),都能同时定量富集。用火焰原子吸收光谱法测定,回收率均在95% ̄110%之间。经地质样品加标准回收实验,结果令人满意。证明这种以磺酸基 相似文献
89.
90.
Diglycidyl ether of 4,4′-dihydroxybiphenol (BPDGE) is a liquid crystalline epoxy. The biphenyl epoxy (diglycidyl ether of 3,3′,5,5′-tetramethyl-4,4′-biphenyl, TMBPDGE) has found great applications in plastic encapsulated semiconductor packaging. Phenol novolac (PN) was used as curing agent. The reaction kinetics of BPDGE/PN and TMBPDGE/PN systems in the presence of triphenylphosphine (TPP) were characterized by an isoconversional method under dynamic conditions using differential scanning calorimetry (DSC) measurements. The results showed that the curing of epoxy resins involves different reaction stages and the values of activation energy are dependent on the degree of conversion. The effects of curing temperature on their phase structure have been investigated with polarized optical microscopy and Wide-angle X-ray diffraction. With proper curing process, BPDGE showed a nematic phase when cured with PN. 相似文献