壳聚糖醋酸溶液粘度的稳定性及其对壳聚糖超滤膜分离效果的影响

分别研究了醋酸水溶液中醋酸的浓度以及壳降糖浓度对壳聚糖醋酸溶液粘度的稳定性的影响,并讨论了壳聚糖溶液的降解对壳聚糖超滤膜分离效果的影响程度。     

壳聚糖溶液稳定性的研究

测定了溶液粘度随壳聚糖浓度、存放时间、温度、搅拌时间及溶液pH值的变化情况。实验表明,溶液粘度随壳聚糖浓度的增加而增大,随存放时间延长和温度升高而降低,随溶液酸性增强而下降。     

脱乙酰甲壳质溶液的粘度及其稳定性

甲壳质,聚(1,4-2-乙酰氨基-2-脱氧-β-D-葡萄糖)是一种在自然界广泛而大量存在的多糖,甲壳质有许多衍生物,脱乙酰甲壳质(下称CTS)是其用途最广也是最为重要的衍生物。由于脱乙酰甲壳质作为溶液被使用及存放时,必须在酸性环境中,基于此,本文从CTS的甲酸、乙酸以及甲、乙酸的异丙醇、乙醇、丙酮溶剂体系的溶液来研究其粘度及稳定性,并从溶液的稠度指数K和流动行为指数n来考察其增加稠能力和溶液性质。实验表明,含有异丙醇和乙醇的溶液的粘度,比不含有机溶剂的溶液的粘度高,而含有丙酮的则较低,有机溶液的加入,对溶液的稳定性没有明显的影响,CTS甲酸系统的溶液比乙酸系统的溶液具有较好的稳定性。分子量为5.6×10~5 CTS的增稠能力不及部分水解聚丙烯酰胺,但优于卡拉胶。CTS溶液属假塑性流体,K值随溶液存放时间而下降,但n值却上升,并接近于1。实验发现,抗氧剂维生素C不仅不能增加CTS溶液的稳定性,且对CTS具有明显的促进降解的作用。     

高相对分子质量PAN纺丝溶液的制备

对高相对分子质量ＰＡＮ（聚丙烯腈）纺丝溶液的制备工艺、影响溶液粘度的主要因素以及溶液的流变性能进行了研究。以ＤＭＦ（二甲基甲酰胺）为溶剂,ＰＡＮ需经２ｈ溶胀在８０￣９０℃下溶解４ｈ,可配制成浓度为７％￣９％的纺丝液,属非牛顿性流体。     

提高硫酸亚铁与硫酸亚铁铵溶液稳定性的方法

本文探讨了硫酸亚铁与硫酸亚铁铵在酸性介质中,溶液不稳定性机理,并提出了不稳定性的改进办法。     

水溶性甲壳素衍生物溶液粘度的研究

测定了水溶性甲壳素衍生物水溶液的粘度，及在水溶液中加入NaCl，乙醇对粘度的影响。研究了不同pH值下水溶性甲壳素衍生物的粘度随时间变化的规律；探讨了水溶性甲壳素衍生物在水溶液中分子间的作用力对粘度的影响。     

纤维素氨基甲酸酯溶液的制备及稳定性研究

研究了制备纤维素纤维的新型原料——纤维素氨基甲酸酯(CC)溶液的制备工艺及其稳定性。结果表明:在-5~10℃条件下,用聚合度为350~612的纤维素浆粕(棉浆粕、木浆粕)合成的氮含量(酯化度)为2.34%~3.56%的CC能很好地溶解在质量百分比浓度为8%~11%的NaOH溶液中,形成淡黄色透明溶液,该溶液稳定性良好,可用于纺丝。另外,尿素、AlCl3及ZnCl2在一定范围内对CC有助溶作用。     

药物包衣用EA-MMA共聚物的聚合稳定性研究

以EA(丙烯酸乙酯)和MMA(甲基丙烯酸甲酯)为共聚单体、SDS(十二烷基硫酸钠)/OP-10(壬基酚聚氧乙烯醚)为阴/非离子型复合乳化剂,采用乳液聚合法制备出一种缓释型药物包衣用EA-MMA二元共聚物,并对其聚合稳定性进行了研究。结果表明:当m(SDS)∶m(OP-10)=1∶2.0、w(总乳化剂)=2.0%(相对于体系总质量而言)、w(引发剂)=0.60%(相对于单体总质量而言)、反应温度为80℃和反应时间为4 h时,制成的EA-MMA二元共聚物乳液稳定性较好、外观较佳、单体转化率(93.22%)和乳液固含量(29.85%)相对较高。     

丙烯腈共聚物溶液的流变性和相分离性能研究

通过红外光谱和核磁共振分析,对不同丙烯腈共聚物(PAN1,PAN2)分子结构进行表征。通过哈克流变仪测定溶液流变性,结果表明共聚物的相对分子质量和第二单体含量对溶液流变性有影响。通过扫描电镜观察膜的形态,并通过热力学和动力学对膜形态进行了讨论。PAN2相对分子质量与第二单体含量较高造成相互作用参数偏高,相对PAN1表现出更易分相特征,分相过程中聚合物贫相所占膜的体积分数偏高,形成的膜孔洞较大。     

Synthesis of copolymer of acrylamide with sodium vinylsulfonate and its thermal stability in solution

The copolymer of acrylamide and sodium vinylsulfonate (PAMSVS) was synthesized by inverse emulsion polymerization and its thermal stability in aqueous and saline solution was investigated. Four samples with different monomer ratio were prepared and the thermal degradation of these samples in aqueous solutions was carried out at 90 °C, 120 °C and 150 °C, respectively. The variation of apparent viscosity during the degradation was investigated. The results indicate that all three PAMSVS samples have better performance of heat endurance than polyacrylamide. Moreover, the sample, which contains 3.4% (molar ratio) sulfonic groups, has the most excellent property of heat endurance. The salt tolerance test of these samples was carried out at 57 °C in 5 mmol/L CaCl₂, 5 mmol/L MgCl₂ and mineralized water, respectively. The results show that all three PAMSVS samples exhibit better property of Ca²⁺ ion tolerance than PAM and the best one is the sample, which contains 6.5% (molar ratio) sulfonic groups.     

工业过氧化氢溶液稳定性的研究

根据GB/T 1616—2014《工业过氧化氢》中的过氧化氢含量(W,以质量分数表示)和稳定度(S)的测试方法进行了没加稳定剂及加有稳定剂的不同工业过氧化氢的W,S的测试,探讨了不同温度和不同放置时间对其W,S的影响,以及没有加稳定剂的两种试样混合后的W,S的变化。结果表明:对于没有加稳定剂的W为30.31%,S为96.60%的试样,在温度3～50℃保存96 h后,再在室温为23～25℃中放置60 h,试样的W和S基本不变;W为30.08%,S为90.00%的没加稳定剂的试样,在温度为30～35℃的室外, 30 d内其S基本不变;W为30.39%,S为86.53%的没加稳定剂试样在温度为30～35℃的室外,降解较快,只能保存10 d左右;W为28.58%,S为85.32%的试样添加含量约50μg/g的稳定剂后,其S可达97%以上,在温度为30～35℃的室外,保存35 d,其试样的W和S基本不变;没加稳定剂的不同W和S的试样按体积比1:1混合后,其W值为两种试样W之和的50%,而其S接近原试样中的较低S值。     

疏水缔合聚丙烯酰胺溶液的稳定性研究

用粘度法研究了用模拟胜利油田盐水配制的疏水缔合聚丙烯酰胺溶液在高温下的稳定性。实验发现聚合物溶液粘度下降很快,硫脲和小分子醇类能明显增强聚合物溶液的高温稳定性。其中硫脲能起到抗氧剂的作用,在短期内能使溶液保持较好的稳定性;小分子醇类能与聚合物交联,使疏水缔合聚合物溶液的网状结构得以维持。用硫脲和自制的多羟基化合物以1∶5比例复配后的稳定剂结合了这两类物质的优点,当加入量为100mg/L时,使聚合物溶液的高温长期稳定性有了很大的提高。     

大豆分离蛋白及其接枝物水溶液性质的研究

利用接枝共聚方法得到了大豆分离蛋白(SPI)和2-丙烯酰胺基-2-甲基丙磺酸(AMPS)的接枝共聚物SPI-g-PAMPS,研究了SPI及SPI-g-PAMPS在水中的溶解性、表面疏水性、Zeta电位以及流体力学半径.结果表明SPI-g-PAMPS在等电点附近的溶解性与SPI相比有明显改善,表面疏水性随接枝率的增大而降低,在所测范围内SPI-g-PAMPS体系的Zeta电位值较纯SPI降低.在等电点附近纯SPI的流体力学半径约为800nm左右,接枝改性后减小至140nm左右.     

Rheological studies on the phase dissolution in a block copolymer

The microphase transition in a styrene-butadiene-styrene triblock copolymer was studied by rheometric mechanical spectroscopy. A high-temperature-melt rheological transition from the highly elastic, nonlinear viscous behavior typical of a multiphase structure to linear viscous behavior with insignificant elasticity typical of a single-phase structure was observed. The transition temperature is determined according to the discontinuity of the rheological properties across the transition region, which agrees well with the results obtained from the small angle X-ray scattering data and the expectation of the random phase approximation theory. Maybe for the first time, microphase dissolution was investigated rheologically. The storage modulus (G′) and the loss modulus (G′) increase with time during the process. An entanglement fluctuation model based on the segmental density fluctuations is presented to explain the rheological behavior in this dissolution process. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1155–1164, 1997     

Radiation stability of perfluoroethylene-propylene copolymer

The gel content of crosslinked perfluoroethylene-propylene copolymer was obtained by extraction with fluoro-chloro oil. It was then treated by the Charlesby-Pinner equation. The results obtained revealed that both the gelation dose and the ratio of fracture to crosslinking density decreased with increasing irradiation temperature.     

Study of the mechanism of additives on copper dissolution in monoethanolamine-complexed cupric ion solution

The dissolution of copper in monoethanolamine (MEA)-complexed cupric ion solution containing different additives was studied. Bridging ligands, such as F^–, Cl^–, Br^–, I^–, SCN^–, and oxidizers, including S₂O₈ ^2–, Cr₂O₇ ^2–, MnO₄ ^– were added to this nonammoniacal etching solution to increase the copper dissolution rate. Potentiodynamic methods were employed to elucidate the dissolution mechanism and the corrosion potential (E _corr) was found to shift from 10 to 90 mV as opposed to that of the original solution (0.045 M cupric sulfate and 0.225 M MEA) for bridging ligands. In contrast, some conventional oxidizers were also added in the etchant and the E _corr did not shift obviously. Therefore, we proposed that copper dissolution proceeds through an inner-sphere pathway in solution containing bridging ligands. The electron is transferred from the copper surface into the cupric species through the ligands, which greatly influences the copper dissolution rate. The order of effectiveness of these ligands is SCN^– > I^– > Br^– > Cl^– > F^–, which is related to their polarizability.