Tracks of Charged Particles in High Polymers

Heavily ionizing particles create trails of damage as they move through materials. In both addition and condensation polymers these trails can be selectively dissolved so that the sites and the directions taken by the moving particles are revealed. These materials thus serve as simple detectors of heavily charged particles.     

高聚物在农业非点源污染控制中的应用

农业非点源污染作为我国地表水的主要污染来源已经成为环境科技领域关注与研究的热点问题。目前,解决非点源污染的主要途径包括多水塘系统、缓冲带、湿地处理以及降水促渗等技术。其中以施用高聚物为促渗手段,强化降水向土壤中渗透的技术,是从源头上控制非点源污染的有效措施。为此综述了高聚物改良土壤,增加土壤对降水的渗透性,延缓并削减降水地表径流,降低非点源污染负荷的效用,以期拓宽我国非点源污染控制的技术途径。     

3种剂型保水剂的特性比较

通过对保水剂3种不同剂型(大颗粒、小颗粒、粉末)的吸水性能、保水性、溶胀度和吸水次数等保水特性的研究，结果证明3种不同剂型的保水剂均具有较强的吸水性和保水性，吸水倍数能达到自身质量的几百倍，开始吸水时快，以后较慢，饱和后不再吸水，且在室内均能保持水分达4d之久，3种剂型保水剂均能反复利用多次。可为保水剂使用者了解保水剂的特性和正确使用保水剂提供理论依据。     

Microstructure of Polymers by Tritium Autoradiography

Polystyrene, polypropylene, and polyethylene, containing tritiumlabeled additives and crystallized in thin films, were examined with autoradiographic stripping film. In the structures formed by isotactic polystyrene, tritiated atactic polymer concentrated in specific patterns in the outer regions. Polypropylene spherulites showed marked differences in the distribution of the tritiated additive, dilauryl thiodipropionate, whenever their optical properties also differed. Autoradiographs of polyethylene spherulites containing low molecular weight tritiated polyethylene exhibited concentric ring patterns similar to those observed on viewing the polymer film in a polarizing microscope.     

熔融共混对聚合物性能的影响

在设定的工艺条件下,调整聚合物之间的比例,并加入偶联剂和热塑性弹性体,采用单、双螺杆挤出机组对聚丙烯(PP)、聚苯乙烯(PS)、高密度聚乙烯(HDPE)进行挤出共混,利用扫描电子显微镜和动态热机械分析仪对混合材料的界面结合状况和弹性模量变化进行分析。研究结果表明:加入偶联剂,当PP∶HDPE为8∶2时,抗弯强度提高了49.5%;PS∶PP为8∶2时,抗拉强度提高近50%。聚合物的熔融共混可以改善物理力学性能和界面相容性,并且为废旧热塑性聚合物的回收利用提供了新的有效途径。     

Polymers, fractals, and ceramic materials

Concepts borrowed from polymer science have been applied to tailor the properties of inorganic materials, especially those derived from amorphous precursors. Fractal geometry can be used to characterize macromolecular precursors and to relate their structures to kinetic growth processes. Within the silica system, for example, it is possible to manipulate the conditions of solution polymerization to yield a variety of macromolecules from branched chains to smooth colloidal particles.     

高吸水树脂耐盐性的改进方法

从高吸水性树脂的结构和吸水机理出发,结合Flory公式,探讨了影响高吸水树脂吸水性能的各种因素,尤其是外部盐溶液的影响,对改进高吸水树脂耐盐性的几种方法:如亲水基团多样化、引入长链疏水单体、选择合适的交联剂、制备互穿网络高吸水树脂、与其他成分复合等进行了重点阐述。     

几种矿物复合保水剂的盆栽试验研究

水资源不仅是农业的重要资源,同时也是影响农业环境的重要因素[1-3],节水技术对高效利用资源和防止面源污染均有重要影响。保水剂节水效果明显,从20世纪60年代开始,美国、日本等发达国家开始研究[4],但因价格高而限制了推广应用。加入矿物制成复合保水剂是降低成本的重要技术途径[5]。磷矿粉复合保水剂需加入浓硫酸进行预处理,工序较烦且耗酸[6]。菱镁     

功能高分子材料在山西省土地荒漠化防治中的应用

山西省地处沙漠化扩展的边沿,土地荒漠化治理任务艰巨。功能高分子材料具有突出的保水性能,国际上已广泛应用于荒漠化治理中。针对山西省土地荒漠化的现状,综述了功能高分子材料在改善山西省土地荒漠化中的应用前景和应用技术。     

Materials science. Polymers go with the flow

The flow of polymer melts and solutions differs substantially from that of other liquids, because the long polymer chains can become entangled and cannot cross each other freely in their motion. In his Perspective, Marrucci provides an overview of theoretical attempts to explain polymer flow. He highlights the report by Bent et al., who have performed sophisticated experiments on linear polymers that prove key elements of the latest theory. Furthermore, the approach used by the authors will become an important experimental tool for investigating more complex polymer systems.     

分子印迹聚合物制备新进展

分子印迹技术是当今科学研究的热点之一。介绍了分子印迹技术的原理以及沉淀聚合法、种子溶胀悬浮聚合法、表面模板聚合法等几种制备分子技术聚合物方法的最新研究进展。     

基态非简并的共聚物的掺杂机制

根据共聚物掺后电导及光学性质的改变，提出了基态非简并的共聚物的掺杂机制。沿链是极化子和双极化子态，而链间是由于双极化子的跳跃；较好地解释了有关实验事实。     

L-苯丙氨酸分子印迹聚合物的制备及其性能研究

以L-苯丙氨酸为模板分子，口一甲基丙烯酸和4-乙烯基吡啶为功能单体，二甲基丙烯酸乙二醇酯和1，4-二乙烯基苯为交联剂，二甲亚砜为溶剂，分别采用本体聚合、乳液聚合和牺牲硅胶法制备分子印迹聚合物．利用氮气吸附实验测定聚合物颗粒的比表面积和孔容。激光粒度分布仪测定颗粒尺寸分布范围和分布曲线．实验表明：牺牲硅胶法制备的分子印迹聚合物具有最大比表面积As=279m^2／g，颗粒分布与薄层层析硅胶-H相近，对L-苯丙氨酸最大饱和吸附量为33．89mg／g，静态分离因子口：1．68，动态分离因子a''=1．227．