甲壳素、壳聚糖的化学改性及其衍生物应用研究进展

简要评述了甲壳素和壳聚糖化学改性的研究进展，讨论了酰化，醚化，酯化，接枝和交联等化学改性方法，简要介绍甲壳素衍生物在化妆品，医学和环保方面的应用，并提出了其发展过程中存在的一些问题，对发其发展趋势作了预测。     

微量元素既可载舟又可覆舟

“先天不足”和“后天失调”的全球性“元素病”，引起了各国政府的关注。中国政府出台了一系列法律文件，成立了国家级的相应机构进行调研和治理。与此同时，加大了元素科学和生命科学的教育和宣传力度，取得可喜的成绩，控制了“碘缺乏病”和“硒缺乏病”，儿童锌缺乏率和儿童铅超标率下降。为了减少各种慢性病的发病率，     

有机分子的拓扑结构及其应用

通过研究新教材课后习题，借助拓扑学基本原理，建立了有机分子拓扑结构，分析了有机分子不饱和度的内涵，阐明了计算各类有机分子不饱和度的原理，介绍了书写有机分子结构和有机反应方程式的技巧，为学习和理解有机化学提供了新的思路和视角。     

时间分辨激光光散射测量系统

自选设计，装配了一套时间分辨的激光光散射测量系统，该系统摄像机，录像机，计算机和自编的软件实现了一体化的数据采集，显示和分析过程，本文给出了该系统的应用实例，球晶的光散射和环氧树脂的固化反应诱导的相分离过程。     

高中生对化学误解的成因分析及纠错建议

通过日常观察和问卷调查，发现浙江省高中生普遍存在对化学的误解，从高中化学课程及考纲的内容探讨了其成因，同时列举了若干与教学相关的事实，并给出了对考纲的建议；列举了多个有机试题命题不严谨和一线教师课堂讲述不严谨的案例，反思了其原因和后果，随后给出了相关建议。     

VOCs污染控制技术与吸附催化材料

简述了VOCs对环境和对人类健康的主要危害，介绍了常见的VOCs污染控制技术，包括回收技术和销毁技术，其中较详细地介绍了吸附法和催化燃烧法的特点及其进展，指出在吸附技术和催化技术里，吸附剂和催化剂扮演着重要角色，本文对这两类环境净化材料的进展和存在问题也作了相应的介绍。     

La2O3掺杂对SrTiO3压敏电容双功能陶瓷显微结构及电性能的影响

用CALPHAD技术优化计算了稀土卤化物熔盐TbCl3-ACl(A=Li，Na，K，Rb，Cs)五个二元系相图以及其热力学性质。优化采用了短程有序-扩展似化学模型，得到了热力学性质和相图自洽一致的结果，并与相应的实验相图进行了比较，对其中差异的部分进行了分析和修正。讨论了热力学优化结果，并探讨了过剩热力学性质变化的规律和特征。     

温度对含硅聚酰亚胺膜气体分离性能的影响

合成了次联苯基型合硅聚酰亚胺（ＳＩＤＡ－ＢＤＡ），研究了其均质膜对Ｈ２，Ｏ２和Ｎ２的透过分离性能与温度的关系，随着温度的升高，气体的透过系数和扩散系数增大，而溶解系数和选择系数则降低，此外，我们还讨论了气体在膜中的透过活化能，扩散活化能和吸着热。     

毛细管气相色谱直接柱内进样技术的研究

发展了一种新型进样技术，使样品直接进入位于炉箱内的色谱柱内，样品的汽化，溶质聚焦和分离过程都在炉箱里一次控制完成，不再需要对进样器的温度和其它流量进行控制，极大地简化了进样器的设计和制作 ，改善了定量重复精度，减少了沸点歧视效应在炉箱里一次汽化     

涂钼石墨管石墨炉原子吸收法测定镓,铟和铊热蒸发行为的探讨

本文从热力学和化学动力学的角度对消除干扰及提高吸收灵敏度的机理进行了探讨，认为在涂钼石墨管中，镓，铟和铊主要以Ｇａ２Ｏ，Ｔｌ２Ｏ和ＩｎＯｘ形式与ＭｏＯ３形成稳定的烧结物，使初始挥发温度大大提高，减少了干燥，灰化前处理过程被测物的分子挥发逸失，由于钼元素参与镓，铟和铊的原子化反应，从而改变了原子化，提高了原子化效率。     

短链支化对低分子量聚乙烯结晶及熔融行为的影响

研究了金属茂催化的低分子量支化聚乙烯和线性聚乙烯的结晶及熔融行为 ,发现支化聚乙烯的结构与线性聚乙烯相同为正交结构 ,但晶格略有膨胀 .支链的存在对熔融行为影响不大 ,两种聚乙烯的熔点均随结晶温度的升高而非线性增加 ,表现出低分子量样品的共同特征 .但支链的存在对结晶行为却有很大的影响 ,主要是由于支链的存在降低了晶体的结晶速率从而影响结晶过程 ,使得低分子量的支化聚乙烯的结晶行为与高分子量线性聚乙烯的结晶行为相似而与低分子量的线性聚乙烯不同 .动力学分析表明 ,低分子量的支化聚乙烯的结晶生长方式的转变温度比同等分子量的线性聚乙烯降低了约 2 0℃     

Gel permeation chromatography of branched polyethylene

The effect of long-chain branching must be considered in gel permeation chromatography to evaluate the molecular weight polydispersity of branched polyethylenes. Osmotic molecular weights of fractions of branched polyethylene were correlated with elution volumes; weight-average and number-average molecular weights of a branched polyethylene were determined. Molecular weight changes on crosslinking polyethylene by ionizing radiation are accompanied by branching and cannot be simply interpreted by gel permeation chromatography.     

不对称茂金属[Me~2C(Cp)(Ind)]ZrCl~2催化剂制备支化聚乙烯的 研究

本文报道以[Me~2C(Cp)(Ind)]ZrCl~2为主催化剂,MAO为助催化剂,仅以乙烯为单体制备支化聚乙烯的结果。     

Pyrolysis and gas chromatography of plasma-polymerized ethylene

Plasma-polymerized polyethylene (PPE) obtained on a radio-frequency glow discharge has been analyzed by flash pyrolysis combined with in-line hydrogenation and gas chromatography. The pyrogram of a bulk powder PPE, which had been characterized by both infrared spectroscopy and density measurements, was compared with a 400 Å thick PPE film deposited directly on the pyrolysis probe. Although the two pyrograms have a qualitative resemblance, they are substantially different from that of conventional branched polyethylene (PE). Some of the fragments exhibited by the deposited PPE are also present in pyrograms of 1,4-polybutadiene. It is evident that the deposited film is a highly branched and unsaturated network polymer with a random arrangement of these structural features.     

Dual functional catalysis for ethylene polymerization to branched polyethylene. I. Evaluation of catalytic systems

Synthesis of low-density polyethylene, that is, a density of less than 0.925 g/cm³, has traditionally been accomplished by the use of free-radical initiators at high ethylene pressures or of an alpha olefin comonomer such as 1-butene at lower pressures. We investigated an alternative route to branched, low-density polyethylene with a single monomer, ethylene, as the feed in conjunction with multicomponent catalyst systems capable of in situ dimerization of ethylene and subsequent copolymerization to produce low-density polyethylene. This article discusses the details of the evaluation of a number of dual-functional systems based on Ziegler-Natta catalysts. Specific, well defined, dual-functional catalyst systems which could easily produce branched, low-density polyethylene with levels of 20–30 branches per 1000 carbon atoms were developed. Variations in the relative number of component catalysts resulted in systematic, predictable changes in the properties of the polyethylene produced, which demonstrated the utility of the dual-functional catalyst concept.     

Dilute solution properties and phase separation of branched low-density polyethylene

Viscosity, light scattering, and precipitation temperature measurements on dilute solutions of high-density and low-density polyethylene fractions have been carried out and a theory by Flory for phase equilibrium of linear polymers has been extended to branched polymer. From the results, it is shown that the entropy parameter ψ, depends on branching; a method for the determination of long-chain branching in polymer fractions is proposed combining precipitation temperature and molecular weight measurements. The method has been applied to the evaluation of long-chain branching in low-density polyethylene.     

Cleavage of branched polyethylene by chemical filling

Branched polyethylene, melt-crystallized in commercial fabrication processes, cleaves into two layers when exposed to a prolonged “chemical filling” treatment (i.e., formation of filler in situ by interdiffusion of two reactive permeants). Cleavage has been observed in film and blown bottles. With film, progressive changes in experimental conditions from one sample to another, shifted the cleavage plane from near the surface to deeper lying planes. Separation of a thin surface layer requires more filler deposit than does separation into layers of more equal thickness. These observations suggest that a well defined layer structure may exist in branched polyethylene and that cohesive bonding is stronger between layers near the surface of the film than it is between deeper lying layers. Linear polyethylene showed slight layer separation after prolonged chemical filling, but clean cut separation of large areas was not achieved. This behavior may indicate that the cohesive bonding between layers is much stronger in linear polyethylene than in branched polyethylene.     

PVT properties of polyethylene copolymer melts

PVT properties of four polyethylene random copolymers (ethylene-propylene, ethylene-1-butene, ethylene-1-hexene, and ethylene-1-octene) and linear polyethylene were measured at temperatures from 313 to 493 K and pressures up to 200 MPa. Dependence of properties such as specific volume, thermal expansion coefficient, isothermal compressibility, and characteristic parameter of equations of state on the length of the polymer branched chains were examined. It was found that the length of the branched chain did not affect the thermal expansion coefficient and isothermal compressibility. The specific volume of copolymers having longer branched chains were slightly larger than those copolymers with short branched chains.     

SOLUTION CRYSTALLIZATION OF METALLOCENE SHORT CHAIN BRANCHED POLYETHYLENE:MORPHOLOGY AND MECHANISM*

Solution crystallization of metallocene short chain branched polyethylene (SCBPE) was carried out and very nicesingle crystals were obtained. Compared with single crystals grown from linear polyethylene, SCBPE single crystals are dirtydue to intermolecular heterogeneity The crystal morphology changes with crystallization temperatures. Lozenge, truncatedlozenge, hexagonal, rounded and elongated crystal morphologies have been found at much lower crystallization temperaturethan in linear polyethylene. The electron diffraction shows there is a possibility that the single crystals may have hexagonalpacking in a crystallization temperature range. The lateral habits of single crystal are discussed based on roughening theories.     

合成分枝型聚乙二醇的简便新方法

以赖氨酸和mPEG5000为起始物,利用多肽合成中常用的保护、缩合和脱保护等方法合成了在生物医学领域中具有重要应用价值的分枝型聚乙二醇.用该方法形成的分枝型PEG在有机相中以缩合反应的方式一步完成,反应条件温和,且有较高的产率(61%).各步产物的表征都与其结构一致.最终产物分枝型PEG的¹HNMR的表征结果与其结构吻合.