Role of epoxidized natural Eucommia ulmoides gum in modifying the interface of styrene‐butadiene rubber/silica composites

Eucommia ulmoides gum (EUG) is a renewable and sustainable polymer, which could be used as rubber or plastic by altering its crosslinking density while the complicated extracting process and nonpolar molecular chains limited its application. In this effort, a novel extraction method was introduced, which could simplify the extraction process of EUG. Then, the extracted EUG‐chloroform (CHCl₃) solution was directly used to prepare epoxidized EUG (EEUG) with an epoxy degree of 40.0% to improve its polarity. The epoxidized natural EUG exhibiting both polar and nonpolar motives had an advantage in working as an interfacial compatibilizer for polymer composites, especially bio‐based composites due to its inherent biocompatibility. Accordingly, the role of EEUG in modifying the interface of styrene‐butadiene rubber (SBR)/silica composites were explored. The results showed that EEUG in SBR/silica composites acted not only as a compatibilizer but also as a constructure generating better mechanical properties than other compatibilizers, such as silane couplings, Si‐69 and KH‐550, and epoxidized natural rubber (ENR). The simplified extracting process and the epoxy modification of EUG would extend its application in rubber materials, medical materials, and biopolymer materials.     

Application of ionic liquids based enzyme-assisted extraction of chlorogenic acid from Eucommia ulmoides leaves

A new approach for ionic liquid based enzyme-assisted extraction (ILEAE) of chlorogenic acid (CGA) from Eucommia ulmoides is presented in which enzyme pretreatment was used in ionic liquids aqueous media to enhance extraction yield. For this purpose, the solubility of CGA and the activity of cellulase were investigated in eight 1-alkyl-3-methylimidazolium ionic liquids. Cellulase in 0.5 M [C6mim]Br aqueous solution was found to provide better performance in extraction. The factors of ILEAE procedures including extraction time, extraction phase pH, extraction temperatures and enzyme concentrations were investigated. Moreover, the novel developed approach offered advantages in term of yield and efficiency compared with other conventional extraction techniques. Scanning electronic microscopy of plant samples indicated that cellulase treated cell wall in ionic liquid solution was subjected to extract, which led to more efficient extraction by reducing mass transfer barrier. The proposed ILEAE method would develope a continuous process for enzyme-assisted extraction including enzyme incubation and solvent extraction process. In this research, we propose a novel view for enzyme-assisted extraction of plant active component, besides concentrating on enzyme facilitated cell wall degradation, focusing on improvement of bad permeability of ionic liquids solutions.     

基于密炼接枝工艺的杜仲胶改性橡胶沥青效果分析

杜仲胶为中国产特有的一种天然橡胶,具有可硫化或者接枝的双键结构。为解决橡胶沥青中胶粉与沥青相容性不足从而导致施工和易性差的问题,采用接枝工艺在杜仲胶与胶粉、沥青之间建立紧密化学链接是一个十分有效的技术手段,但限于溶剂接枝工艺复杂不利于工业化生产的现状,提出在密炼机中将接枝物与杜仲胶通过高温密炼的方式将其接枝改性。为了验证密炼接枝能否达到溶剂接枝的改性效果,开展了普通胶粉、密炼杜仲胶改性胶粉、溶剂接枝杜仲胶改性胶粉和密炼接枝改性胶粉4种胶粉对沥青的改性试验,通过常规与SHARP的沥青宏观试验方法和红外光谱、荧光显微镜和扫描电镜等微观观测方法进行了测试,分析了不同杜仲胶接枝方法对橡胶粉的影响。试验结果表明：高温密炼可以使橡胶粉产生脱硫和杜仲胶硫化等化学反应,从而改性橡胶沥青性能;并且能使小官能团在高温和机械作用下接枝到杜仲胶上,与橡胶粉混合后使其具有更高的化学活性,能与沥青建立更为有效的化学联系;杜仲胶无论密炼还是溶剂接枝均能与橡胶粉和基质沥青产生交联反应、构建交联网络,使沥青内部形成稳固的空间交联结构,显著提升橡胶沥青的施工和易性和体系稳定性。     

高效液相色谱法同时测定杜仲中的几种多酚酸——超声助提及微波助提和热回流提取技术的比较

微波、超声波和热回流提取技术分别用于提取杜仲中的绿原酸、咖啡酸、没食子酸、原儿茶酸和香草酸,并用高效液相色谱进行分析.考察了提取时间和溶剂对提取效果的影响.结果表明：超声波助提和热回流提取分别需90 min和120 min才能达到最大提取,而微波助提仅需50 s就可达到.在微波助提和热回流提取中,水比甲醇提取效果要好,而在超声波助提过程中,用甲醇作溶剂获得的提取率比水高.3种提取方法的重现性均较好.综合来看,微波助提比超声波助提和热回流提取技术效果更好,更有利于杜仲中酚酸的提取.     

大孔吸附树脂纯化杜仲叶加工剩余物中的京尼平苷酸

以杜仲叶加工剩余物为原料,研究(比较)了S-8、AB-8、D101和X-5 4种大孔吸附树脂对杜仲中的降血压活性成分京尼平苷酸(GPA)的吸附及脱附性能。以S-8型树脂吸附-水脱附工艺纯化GPA的优化工艺为:脱附剂用量300mL、脱附流速3mL/min、上柱液pH值1.0,脱附过程的最大影响因素为脱附剂流速,GPA的脱附率达89.64%,GPA含量由7.23%提高到45.18%。     

杜仲离体培养愈伤组织药物成份定性分析

本文对杜仲离体培养愈伤组织的药物成份进行了初步的定性分析,其结果和杜仲树皮的定性分析结果相一致,这表明该愈伤组织中仍保持了杜仲树体内所含有的次生物质,从而为杜仲通过细胞大量培养实现药物成份工业化生产提供了理论依据。     

杜仲叶片蒸腾速率的因子分析

利用ＬＩ－１６００稳态气孔计测定了杜仲叶片蒸腾速率的日变化，以及水分胁迫下蒸腾速率的变化，探讨了环境因子对杜仲叶片蒸腾速率的影响。     

杜仲叶片对土壤水分胁迫的适应性研究

二年生杜仲实生苗在不同土壤干旱条件下的盆栽试验结果表明，杜仲对土壤水分胁迫有很强的适应能力，这种适应能力通过三种调节过程实现，即通过叶片水分饱和亏缺和Ｋ＾＋含量的反馈控制实现的气孔运动的调节，通过脯氨酸积累实现的渗透调节，以及通过活必氧浦除剂（如过氧化物酶）活性变化实现的对自由基平衡的调节。     

新型功能材料杜仲胶的研究与应用

从高弹性杜仲胶的诞生及结构的发现,从杜仲胶硫化过程3个阶段及相对应的3类材料的发现,从杜仲胶材料工程学的形成及“橡—塑统一材料谱”概念的提出,论证了杜仲胶的广泛应用及发展前景。提出了杜仲胶、天然橡胶、顺丁橡胶共混的新观点。     

杜仲子与杜仲皮的毒性比较研究

目的：研究杜仲子的毒性大小,及其与杜仲皮的毒性比较,为其进一步开发利用提供依据。方法通过小鼠的急性毒性实验、骨髓微核实验、精子畸形实验、大鼠的慢性毒性实验来研究杜仲子的毒性大小和与杜仲皮的毒性比较。结果小鼠的急性毒性实验中,给药组都无小鼠死亡;小鼠骨髓微核实验及精子畸形实验中,杜仲子和杜仲皮与正常组对比在统计学中无差异。大鼠的慢性毒性实验中,杜仲子及杜仲皮可以影响食物利用率、血常规和肝功能,还可以影响肝、脾、睾丸、卵巢的脏体系数;对大鼠脏器进行病理组织学检查,未见明显异常。杜仲子与杜仲皮的毒性比较无差异。结论杜仲子和杜仲在急性毒性实验、骨髓微核实验、精子畸形实验中显示无毒性;在慢性毒性实验中,杜仲子和杜仲会影响食物利用率、血常规和肝功能,也会影响肝、脾、睾丸、卵巢生长,有慢性毒性。但杜仲子与杜仲皮的毒性无差异。