黄原胶发酵生产工艺研究

本文研究} Xanthomonas Campestris XC-82. 5R5菌株的黄原胶最适发酵工艺条件.分析了不同碳源底物及溶氧水平对发醉过程的影响，确定了发酵最佳温度、初始pH值、菌龄，揭示了以菜油替代PPE作消泡剂的优点，同时认为不宜采用添加HZO:水的方式来改善发酵液的溶氧状况一实验表明，最佳摇瓶发酵工艺条件:蔗糖作碳源要优于葡萄糖，最适发醉温度’为28-32'C，接种菌龄为28hr，初始pH为7. 2;消泡剂为。.1%一。.2%菜油.     

Quasiliving Carbocationic Polymerization. XVII. Synthesis Of Poly (Styrene-β-Isobutylene-β-Styrene)

Poly(styrene-b-isobutylene-b-styrene) has been synthesized by sequential carbocationic polymerization under quasiliving conditions at -90°C. The quasiliving synthesis was effected by first continuously and slowly condensing gaseous isobutylene (IB) to a bifunctional initiating system (p-dicumyl chloride/TiCl₄) dissolved in a hexane-methylene chloride (60:40 v/v) mixture. After the quasiliving polyisobutylene (PIB) sequence had reached a desired molecular weight, styrene (St) was continuously and slowly added to produce the polystyrene (PSt) sequence. The products consisted of the target triblock. However, due to initiation by impurities and possibly to chain transfer to both IB and St, it also contained diblocks and small amounts of homopolymers. While the latter could be removed by selective fractionation, the triblocks and diblocks could not be separated. The mechanism of quasiliving polymerization leading to PIB/PSt blocks is discussed.     

Green synthesis of Ni‐Cu‐Zn ferrite nanoparticles using tragacanth gum and their use as an efficient catalyst for the synthesis of polyhydroquinoline derivatives

Ni_0.35Cu_0.25Zn_0.4Fe₂O₄ MNPs were synthesized using tragacanth gum as biotemplate and Metals nitrate as the metal source by the sol–gel method. The sample was characterized by powder X‐ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM) and energy dispersive X‐ray analysis (EDX). The nanoparticles exhibit ferromagnetic behaviour at room temperature, with a saturation magnetization of 52.76 emu/g and a coercivity of 80.14 Oe. Thereupon, Ni‐Cu‐Zn ferrite nanoparticles as an efficient catalyst was used for the synthesis of polyhydroquinoline derivatives via multi‐component reactions under microwave irradiation. Simple work‐up, mild reaction conditions, short reaction times, use of an economically convenient catalyst, and excellent product yields are the advantageous features of this method. The catalyst could easily be recycled and reused few times without noticeable decrease in catalytic activity.     

La relation structure chimique–propriétés physiques des galactomannanes extraits de la caroube

Carob galactomannan fine chemical structure is closely related to the physical behavior developed in aqueous solution. Three elements of structural characterization are mainly described in the literature: the degree of galactose substitution, chain length, and galactose units distribution. This review article will attempt to highlight the impact of different structural features on physical properties such as solubility, viscosity, formation of hydrogels or gels in combination with other saccharides. The impact of industrial purification process on the structure and physical properties is also developed.     

Interactions between flaxseed gums and WPI-stabilized emulsion droplets assessed in situ using diffusing wave spectroscopy

Diffusing wave spectroscopy (DWS) was used to investigate the behavior of flaxseed gums when added to WPI-stabilized emulsions. The effect of different concentrations (0–0.33% (w/v)) of flaxseed gum, derived from two seed varieties, namely Emerson and McDuff, was studied at acidic and neutral pH. At pH 7.0 and low gum concentrations the dynamic and spatial characteristics of the system remained unchanged. While at gum concentrations from 0.075% to 0.20% a rapid phase separation was observed, at higher concentrations phase separation was retarded because of the increased background viscosity slowing down the mobility of the emulsion droplets. At pH 3.5, the difference in overall electrical charge between the gum (negative) and the protein on the emulsion surface (positive) led to electrostatic interactions. While at low concentration of flaxseed gum the general characteristics of the emulsions were not significantly different, at intermediate concentrations, bridging flocculation occurred. When sufficient flaxseed gum was present, the emulsion droplets mobility was arrested in a gel-like state. In spite of the compositional differences in the ratio of acidic and neutral fraction between the two polysaccharides extracted from different seed varieties, at both values of pH the behavior of the emulsions after addition of the polysaccharide was comparable.     

亚麻籽胶为壁材制备沙棘油微胶囊研究

本文采用喷雾干燥法制备沙棘籽油为芯材、亚麻籽胶为壁材的微胶囊,并以微胶囊化效率和含油率为考察指标,考察了制备工艺.结果表明,最佳喷雾干燥工艺条件：进风温度为180℃,出风温度为80℃,雾化器转速24000r/min,进料速度为40.21mL/min.在此工艺条件下沙棘籽油的微胶囊化效率为87.12%,含油率为45.09%.     

Enhanced transport of zerovalent iron nanoparticles in saturated porous media by guar gum

In order to ensure adequate mobility of zerovalent iron nanoparticles in natural aquifers, the use of a stabilizing agent is necessary. Polymers adsorbed on the nanoparticle surface will give rise to electrosteric stabilization and will decrease attachment to the surface soil grains. Water saturated sand-packed columns were used in this study to investigate the transport of iron nanoparticle suspensions, bare or modified with the green polymer guar gum. The suspensions were prepared at 154 mg/L particle concentration and 0.5 g/L polymer concentration. Transport experiments were conducted by varying the ionic strength, ionic composition, and approach velocity of the fluid. Nanoparticle deposition rates, attachment efficiencies, and travel distances were subsequently calculated based on the classical particle filtration theory. It was found that bare iron nanoparticles are basically immobile in sandy porous media. In contrast, guar gum is able to ensure significant nanoparticle transport at the tested conditions, regardless of the chemistry of the solution. Attachment efficiency values for guar gum-coated nanoparticles under the various conditions tested were smaller than 0.066. Although the calculated travel distances may not prove satisfactory for field application, the investigation attested the promising role of guar gum to ensure mobility of iron nanoparticles in the subsurface environment.     

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.     

快速分析松脂澄清脂液中松节油含量的新方法

本文用统计方法研究思茅松松脂澄清脂液中松节油含量与酸值的相关关系，建立了不同于通常所用蒸馏法的新分析方法──酸值法。新方法快速、简捷、准确、经济、缩短分析时间５０分钟（７１％）；重复试验的极差的均值为０．１％，降低分析成本７０％；已用于云南省地方标准。     

砷钼杂多酸—罗丹明B-阿拉伯树胶显色体系的研究——分光光度法测定钢铁和锡基合金中的痕量砷

本文提出了一个测定砷的高灵敏度分光光度法。探讨了在阿拉伯树胶存在下定量形成砷钼杂多酸-罗丹明B离子缔合络合物的适宜条件。该显色反应在室温下可稳定25小时。表观摩尔吸光系数为1.99×10~5lmol~(-1)cm~(-1)。在0—8μgAs/25ml范围内遵守比尔定律。络合物的组成为[As]:[R]=1∶4。本法满意地用于分析钢铁和锡合金中的痕量砷。