槐豆胶热水溶和冷水溶部分流变性的比较研究

对槐豆胶冷水溶部分和热水溶部分的流变性进行了比较研究,结果表明,槐豆胶在冷水中溶解和在热水中溶解,其流变性有所不同。     

阳离子瓜耳胶的合成

以环氧氯丙烷、三甲胺、盐酸为原料,合成中间体3-氯-2-羟丙基-三甲基氯化铵,进而中间体与瓜耳胶反应。着重考察了由中间体制备阳离子瓜耳胶时,各种因素对其理性指标的影响。结果表明:反应温度35~40℃,反应时间25 h,反应液的pH值控制在6~8。在此条件下,阳离子瓜耳胶的含氮量的质量分数达1.70%(标样1.66%),25℃下,其0.5%的水溶液粘度大于3 600 Pa.s(标样3 000 Pa.s)。产品的红外光谱图与法国罗地亚公司的样品谱图相符。     

Antibacterial Broad-Spectrum Dendritic/Gellan Gum Hybrid Hydrogels with Rapid Shape-Forming and Self-Healing for Wound Healing Application

Treating wound infections is a difficult task ever since pathogenic bacteria started to develop resistance to common antibiotics. The present study develops hybrid hydrogels based on the formation of a polyelectrolyte complex between the anionic charges of dopamine-functionalized Gellan Gum (GG-DA) and the cationic moieties of the TMP-G2-alanine dendrimer. The hydrogels thus obtained can be doubly crosslinked with CaCl₂, obtaining solid hydrogels. Or, by oxidizing dopamine to GG-DA, possibly causing further interactions such as Schiff Base and Michael addition to take place, hydrogels called injectables can be obtained. The latter have shear-thinning and self-healing properties (efficiency up to 100%). Human dermal fibroblasts (HDF), human epidermal keratinocytes (HaCaT), and mouse monocyte cells (RAW 264.7), after incubation with hydrogels, in most cases show cell viability up to 100%. Hydrogels exhibit adhesive behavior on various substrates, including porcine skin. At the same time, the dendrimer serves to crosslink the hydrogels and endows them with excellent broad-spectrum microbial eradication activity within four hours, evaluated using Staphylococcus aureus 2569 and Escherichia coli 178. Using the same GG-DA/TMP-G2-alanine ratios hybrid hydrogels with tunable properties and potential for wound dressing applications can be produced.     

Liquid-Crystalline Polyurethanes. 5. Polyurethanes Containing the Cholesterol Moiety in the Side Chain

In the preceding papers of this series, we reported the synthesis of liquid-crystalline polyurethanes containing mesomorphic moieties in the main chain and in side chains [1–4]. Liquid crystalline polymers with side groups containing the cholesterol moiety have also been studied [5, 6]. The main focus of attention has centered around the study of phase transitions of acrylic and methacrylic derivatives of cholesterol. This paper describes the synthesis of a new type of liquid-crystalline polyurethane containing the cholesterol moiety in side chains.     

钒（Ⅳ）—硫氰酸盐—结晶紫高灵敏显色反应的研究

在阿拉伯胶存在下,在0.12mol·l~(-1)硫酸介质中,钒(Ⅳ)-硫氰酸盐-结晶紫形成水溶性离子缔合物,该显色体系最大吸收峰在550nm.试剂空白最大吸收在625nm,对比度,表观摩尔吸光系数,钒量在0～4μg/25ml符合比耳定律.考察了40多种常见阴、阳离子的影响。本方法已用于快速直接测定岩矿中的痕量钒,相对标准偏差≤4.1％(n=7～10),标准加入回收率95～105％。     

贮水树脂胶在盆景土壤中的持水能力研究

<正>研究结果表明：贮水树脂胶与土壤的亲和力很强,加入土壤量的０．１％～０．４％树脂胶后,可使土质疏松,持水能力显著提高,植物长势良好,一个月内不用浇水,盆内土壤原有水分较对照损失减少约４倍     

田菁胶分子的势能面和几何构型

用ＧＡＭＥＳＳ中ＭＯＰＡＣ的ＰＭ３程序在全局优化中确定了田菁胶大分子的几何构型和稳定构象,计算了该大分子绕两个旋转轴θ,φ旋转的势能面,结果表明大分子基闭之间不能绕θ,φ轴进行自由旋转。     

磁性瓜尔胶复合微球的制备及其性能研究

采用化学共沉淀法制备了纳米磁性Fe3O4粒子,并用硅烷偶联剂对其进行表面修饰。以Fe3O4作为磁性内核,以戊二醛作为交联剂,采用反相悬浮交联法制备了Fe3O4-阴离子瓜尔胶磁性微球,并用红外光谱、扫描电镜和磁学性质测量系统对样品进行了表征。通过对阿司匹林模型药物的负载实验,发现修饰后的Fe3O4-阴离子瓜尔胶磁性微球具有较好的载药性。     

工艺因素对XG-AM接枝共聚型吸水树脂性能的影响

以APS为引发剂,MBAA为交联剂,采用水溶液聚合法,制备了XG-AM接枝共聚耐盐型高吸水性树脂.分别研究了丙烯酰胺用量、碱用量、聚合温度、交联剂和引发剂用量等因素对树脂吸水性能的影响.采用红外光谱仪、X射线粉末衍射仪对树脂进行了表征和测试.结果表明:黄原胶与丙烯酰胺发生了接枝聚合反应,当m(AM)/m(XG)为6∶1,m(NaOH)/m(AM)为1∶1,聚合温度为60℃,m(MBAA)/m(AM)为0.04∶1,m(APS)/m(AM)为0.07∶1时,树脂对去离子水的吸收倍率可达1 240 g.g-1,对0.9%NaCl溶液的吸收倍率达到235 g.g-1.     

天然杜仲胶乳的制备及表征

采用溶液乳化法制备了杜仲胶乳,考察了乳化配方及乳化工艺对乳化效果的影响,确定了如下制备条件：以杜仲胶的环己烷溶液（杜仲胶的质量分数为6%）为油相胶液,采用1% Brij-52、0.5% Tween-20、0.5%十二烷基苯磺酸钠的三相复配乳化剂体系,油水体积比为1：1.5,乳化方式为高速搅拌（8 000 r/min,10 min）,除溶剂方式为旋转蒸发（-0.09 MPa,40℃）,浓缩方式为离心浓缩（10 000 r/min,10 min）。在优化条件下制备的杜仲胶乳的固含量可达54%,粒径约为330 nm,Zeta电位的绝对值可达57 mV。采用X射线衍射法（XRD）、差示扫描量热法（DSC）、傅里叶变换红外光谱法（FT-IR）、扫描电子显微镜（SEM）和偏光显微镜（POM）对制备的杜仲胶乳进行了表征,结果表明：乳化没有破坏杜仲胶的结晶性能,杜仲胶乳中仍存在大量的微结晶,杜仲胶乳的晶型中以β晶型为主。