反式 -1,4-聚异戊二烯相对分子质量的调节

采用负载钛本体沉淀聚合法,以氢气作链转移剂,制备了不同相对分子质量的反式-1,4-聚异戊二烯(TPI),讨论了老化、氢气调节及塑炼对其相对分子质量的影响,以及不同相对分子质量TPI的结构与性能。结果表明,本体系合成TPI的数均相对分子质量为(5～15)×104,相对分子质量分布为2.00～3.00;门尼粘度为20～120时,随着TPI相对分子质量的降低,其结晶速度提高,结晶度无明显变化,拉伸强度明显降低,扯断伸长率、屈服强度和邵尔A型硬度无明显变化。     

广西古代陶器组成的研究

桂林甑皮岩遗址发现了距今９２４０－１０３７０年的陶片，证实了广西地区从新石器以来就成为我国古代陶器的发源地之一。本工作研究了广西出土的４４块陶片，测定了陶胎的化学和矿物组成。由此表面广西古陶的ＳｉＯ２含量随时代变迁而逐渐增加，而Ｆｅ２Ｏ３含量在明显下降，Ａｌ２Ｏ３的含量也有降低的趋势。     

高职院校化工类专业素质教育目标架构化建设初探

结合目前高职院校化工类专业教学实际,探讨了开展构建化工类专业模块化的素质教育架构的指导思想、设计原则、内容确立的方法和实践要素,以提升学生专业知识、思想品德、人文素质、科学素养等方面素质,培养学生实践能力和创新能力,适应市场经济对高职教育人才培养的要求。     

Supercritical CO2‐assisted synthesis of poly(acrylic acid)/Antheraea pernyi SF blend

Monomer acrylic acid (AA) and initiator azo‐bis(isobutyronitrile)were carried into Antheraea pernyi silk fibroin (SF) fibers using supercritical CO₂ as a solvent and carrier, followed by free radical polymerization at a suitable temperature, resulting in PAA/SF blends. The binary system of CO₂/AA and the ternary system of CO₂/AA/AIBN systems were studied. Different impregnation conditions, such as time, pressure, and concentration of AA in the fluid phase on mass uptake, were studied. Fourier transform infrared spectroscopy and X‐ray diffraction results confirmed that PAA was indeed present in the silk and that there were intermolecular hydrogen bonds between PAA and SF. According to thermogravimetry and DTG, blending with PAA could enhance the thermal stability of SF slightly. The water retention values indicated that the hydrophilic nature of the fibers was improved. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 864–868, 2005     

Separation of 1,3-propanediol from glycerol-based fermentations of Klebsiella pneumoniae by alcohol precipitation and dilution crystallization

The separation of 1,3-propanediol from the glycerol-based fermentation broth of Klebsiella pneumoniae plays an important role during the microbial production of 1,3-propanediol. In this paper, the separation of 1,3-propanediol from fermentative broth by a combination of ultrafiltration and alcohol dilution crystallization was investigated. The broth was first filtered by ultrafiltration, and 99% of cells, 89.4% of proteins and 69% of nucleic acids were removed. The obtained broth was further condensed by vacuum distillation, and then alcohol was added. The macromolecular impurities, such as nucleic acids, polysaccharides and proteins, were precipitated, and inorganic and organic salts were crystallized. The optimal volume ratio of alcohol added to the condensed fermentation broth was determined to be 2:1. As a result, proteins, nucleic acids and electric conductivity decreased by 97.4%, 89.7% and 95.8%, respectively, compared with the fermentative broth. The influences of pH and water content in condensed broth on alcohol precipitation and dilution crystallization were also investigated. The experimental results indicated that alcohol precipitation and dilution crystallization was feasible and effective for the separation of 1,3-propanediol from actual fermentation broth. Translated from The Chinese Journal of Process Engineering, 2006, 6(3): 454–457 [译自: 过程工程学报]     

水热法制备纳米尖晶石型NiFe_2O_4及表征

分别采用水热法、共沉淀法合成了纳米尖晶石型铁氧体—NiFe2O4晶体,对两种方法所合成的样品进行了比较,分析了不同合成方法的优缺点,确定水热法为比较适宜的合成该类复合氧化物的方法,该法合成的NiFe2O4晶体的平均粒径仅为15.9nm,且粒度分布十分均匀。此外,通过对实验结果的测定与分析探讨了影响水热制备的几种可能的因素,确定了水热合成的适宜的沉淀剂为NaOH溶液,水热合成适宜的温度为200℃。     

Self-assembly and crystallization behavior of a double-crystalline polyethylene-block-poly(ethylene oxide) diblock copolymer

The self-assembly and crystallization behavior of a well-defined low molecular weight polyethylene-block-poly(ethylene oxide) (PE-b-PEO) diblock copolymer was studied. The number-average degrees of polymerization for the PE and PEO blocks were 29 and 20, respectively. The molecular weight distribution was 1.04 as determined by size-exclusion chromatography. The PE-b-PEO sample exhibited two melting points at 28.7 and 97.4 °C for the PEO and the PE crystals, respectively. The crystallization of the PE blocks was unconfined, while the crystallization of the PEO blocks was confined between pre-existing PE crystalline lamellae, as demonstrated by simultaneous small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) studies. In the fully crystalline state, both PE and PEO blocks formed extended-chain crystals with PE chains tilted ∼22° from the lamellar normal and PEO chains parallel to the lamellar normal, as evidenced by two-dimensional WAXD study of shear-oriented samples. Regardless of hydrogen bonding among hydroxyl chain ends in the PEO blocks, interdigitated, single-crystalline layer morphology was observed for both PE and PEO crystals. The partial crystalline morphology, where the PE crystallizes and the PEO is amorphous, had the same overall d-spacing as the fully crystalline morphology. A double-amorphous PEO layer sandwiched between neighboring PE crystalline layers was deduced based on a chain conformation study using Fourier transform infrared. The confined crystallization kinetics for PEO blocks was investigated by differential scanning calorimetry, which could be explained by a heterogeneous nucleation mechanism. The slower crystallization rate in the PEO-block than the same molecular weight homopolymer was attributed to the effects of nanoconfinement and PEO chains tethered to the PE crystals.     

水解酸化-好氧生物法处理工业废水

水解酸化—好氧生物处理法是近年提出的一种新型处理工业废水的方法。列举了水解酸化工序在生物处理工业废水中的优点，并就其在啤酒废水、屠宰废水、乳品废水、制浆废水以及制药废水中的应用作了介绍。     

闪蒸法聚乙烯无纺布的研究进展

介绍了无纺布的发展历程以及我国无纺布的现状，着重讨论了开展闪蒸法聚乙烯纺粘型无纺布研究的意义、方法、生产工艺。