共查询到19条相似文献,搜索用时 265 毫秒
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杜仲胶改性高聚物的研究进展 总被引:1,自引:0,他引:1
《高分子通报》2015,(8)
介绍了杜仲胶结构、性能特点、来源以及弹性体的应用研究现状。杜仲胶的结构主要是反式1,4聚异戊二烯,为具有结晶性的有序柔性链;具有耐老化性能好、生热低、耐磨及耐疲劳性能好,结晶状态下具有形状记忆功能等性能特点。其来源主要包括天然提取和人工合成。论文综述了杜仲胶改性塑料及杜仲胶改性沥青、极性与非极性橡胶以及制备记忆材料的性能的研究进展,重点阐述了杜仲胶与极性橡胶与非极性橡胶共混研究。同时,展望了杜仲胶在工业领域的应用。 相似文献
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一种古老而又年轻的天然高分子—杜仲胶 总被引:12,自引:0,他引:12
本文简述了杜仲胶的开发史及资源情况。指出,杜仲胶高弹性体的出现,是其研究开发进入新阶段的标志。指出临界交联度是杜仲胶获得高弹性的关键概念。这种由有序柔性链组成的大分子网络,其高弹性不宜用分子链无规线团的贡献来解释,而是由于大分子网络的整体无序性。 相似文献
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聚氨酯/环氧树脂IPN复合抛光材料的制备及性能研究 总被引:1,自引:0,他引:1
本研究采用聚氨酯与环氧树脂(PU/EP)作为胶黏剂形成互穿网络(IPN),以无机磨料和稀土抛光剂为分散相,通过一定的成型工艺制备成复合抛光材料。通过固化前后的红外光谱,分析了PU、EP两者之间的反应;热重分析表明PU/EP IPN复合抛光材料的耐热性能比纯的PU和EP有显著提高;体视显微镜照片显示该复合抛光材料具有微孔结构;力学及应用性能研究显示当胶黏剂含量为25%时性能最佳;且在PU/EP=2时,抛光后的玻璃透光率保持原有的97%,且耐磨性得到大幅度提高。 相似文献
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聚合物孔材料的合成与应用 总被引:7,自引:0,他引:7
近年来,有关聚合物孔材料的合成及应用研究日趋活跃,已成为现代材料学研究领域的一大热点。本文分别对微孔、介孔和大孔聚合物孔材料的主要合成方法,如胶态晶体模板法、Track-eteh膜模板法、悬浮聚合法和超临界快速降压法等方法,以及聚合物孔材料在传感器材料的合成、化学分离等领域的应用进展情况进行了综述。 相似文献
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López-Franco YL Valdez MA Hernández J Calderón de la Barca AM Rinaudo M Goycoolea FM 《Macromolecular bioscience》2004,4(9):865-874
Mesquite gum sourced from Prosopis velutina trees and gum arabic (Acacia spp.) were characterized using light scattering and Langmuir isotherms. Both gum materials were fractionated by hydrophobic interaction chromatography, yielding four fractions for both gums: FI, FIIa, FIIb and FIII in mesquite gum and FI, FII, FIIIa and FIIIb in gum arabic. In mesquite gum, the obtained fractions had different protein content (7.18-38.60 wt.-%) and macromolecular dimensions (M approximately 3.89 x 10(5)-8.06 x 10(5) g.mol(-1), RG approximately 48.83-71.11 nm, RH approximately 9.61-24.06 nm) and architecture given by the structure factor (RG/RH ratio approximately 2.96-5.27). The mechanical properties of Langmuir monolayers at the air-water interface were very different on each gum and their fractions. For mesquite gum, the most active species at the interface were those comprised in Fractions IIa and IIb and III, while Fraction I the pi/A isotherm lied below that of the whole gum. In gum arabic only Fraction III developed greater surface pressure at the same surface per milligram of material than whole gum. This is rationalized in terms of structural differences in both materials. Mesquite gum tertiary structure seems to fit best with an elongated polydisperse macrocoil in agreement with the "twisted hairy rope" proposal for arabinogalactan proteoglycans. 相似文献
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M W Pfaffl L A van Ginkel J D McEvoy G Maghuin-Rogister H H Meyer 《Fresenius' Journal of Analytical Chemistry》2001,371(8):1092-1097
The certification by inter-laboratory testing of two candidate reference materials (RMs) for the mass concentration of the anabolic agent clenbuterol in bovine eye material is described: RM 674 with ca 10 microg clenbuterol per kg of eye matrix and RM 673 clenbuterol-free eye matrix as the negative control (<0.50 microg kg(-1)). Both candidate RMs were certified by eleven EU laboratories, and sixty-six accepted replicate measurements were included in the "Certification Study". The precision of the measurement process was assessed by calculation of the standard variation determined within each laboratory during the certification step. The study was performed according to the "Guidelines for the production and certification of BCR reference materials" and to "ISO guide 31, 33, and 35". The certified clenbuterol mass concentration for clenbuterol-free eye material CRM 673 (calculated on the basis of clenbuterol as the free base) was <0.50 microg kg(-1). The corresponding concentration for clenbuterol-containing eye material CRM 674 was 9.42 +/- 0.88 microg kg(-1). These certified values are very close to the desired target concentration of <0.5 microg kg(-1) and ca 10 microg kg(-1). This study has demonstrated that successful certification of clenbuterol-containing and clenbuterol-free bovine eye materials is possible. 相似文献
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《中国科学:化学(英文版)》2015,(6)
Organic light-emitting diodes(OLEDs) have been extensively studied since the first efficient device based on small molecular luminescent materials was reported by Tang. Organic electroluminescent material, one of the centerpieces of OLEDs, has been the focus of studies by many material scientists. To obtain high luminosity and to keep material costs low, a few remarkable design concepts have been developed. Aggregation-induced emission(AIE) materials were invented to overcome the common fluorescence-quenching problem, and cross-dipole stacking of fluorescent molecules was shown to be an effective method to get high solid-state luminescence. To exceed the limit of internal quantum efficiency of conventional fluorescent materials, phosphorescent materials were successfully applied in highly efficient electroluminescent devices. Most recently, delayed fluorescent materials via reverse-intersystem crossing(RISC) from triplet to singlet and the "hot exciton" materials based on hybridized local and charge-transfer(HLCT) states were developed to be a new generation of low-cost luminescent materials as efficient as phosphorescent materials. In terms of the device-fabrication process, solution-processible small molecular luminescent materials possess the advantages of high purity(vs. polymers) and low procession cost(vs. vacuum deposition), which are garnering them increasing attention. Herein, we review the progress of the development of small-molecule luminescent materials with different design concepts and features, and also briefly examine future development tendencies of luminescent materials. 相似文献
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浅谈聚氨酯产业现状与发展趋势 总被引:1,自引:0,他引:1
聚氨酯材料是一类广泛应用的高分子材料,本文针对目前我国聚氨酯制品的广泛应用及其产业的迅猛发展,预测了国内聚氨酯三大基础原料甲苯异氰酸酯(TDI)、二苯基甲烷二异氰酸酯(MDI)和聚醚多元醇(PPG)的未来产能,同时从我国人口总量的优势、交通运输业的增长、建筑节能的新需求、休闲市场的新发展及医用材料的应用等几个方面分析了未来拉动聚氨酯产业发展的几大因素,指出国内聚氨酯产业的发展趋势。 相似文献
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Peter S. Given 《Current Opinion in Colloid & Interface Science》2009,14(1):43-47
Though stable in dilute form for very long periods of time, simple mono-emulsifier flavor emulsions based on gum acacia or modified starch are fairly limited in their ability to provide functionality beyond simple dispersion. This review highlights many of the enhancements on traditional emulsions, ranging from new materials to novel combinations of materials and processes. The development of more sophisticated dispersion technologies employing complex mixtures of biopolymers as well as low molecular weight surfactants, and novel multilayered interfacial structures, is on an intersecting course with a growing need for enhanced emulsion functionality in beverages, such as controlled release, protection, taste masking, and targeted delivery. Novel raw materials, molecular assemblies, processes and applications are discussed in this review. 相似文献
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Weng Mouyi Wang Zhi Qian Guoyu Ye Yaokun Chen Zhefeng Chen Xin Zheng Shisheng Pan Feng 《中国科学:化学(英文版)》2019,62(8):982-986
Material identification technique is crucial to the development of structure chemistry and materials genome project. Current methods are promising candidates to identify structures effectively, but have limited ability to deal with all structures accurately and automatically in the big materials database because different material resources and various measurement errors lead to variation of bond length and bond angle. To address this issue, we propose a new paradigm based on graph theory(GTscheme) to improve the efficiency and accuracy of material identification, which focuses on processing the "topological relationship" rather than the value of bond length and bond angle among different structures. By using this method, automatic deduplication for big materials database is achieved for the first time, which identifies 626,772 unique structures from 865,458 original structures.Moreover, the graph theory scheme has been modified to solve some advanced problems such as identifying highly distorted structures, distinguishing structures with strong similarity and classifying complex crystal structures in materials big data. 相似文献
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Damping performance of Eucommia ulmoides gum 总被引:1,自引:0,他引:1
Eucommia ulmoides gum(EU gum),known as gutta percha in Southeast Asia,is a natural polymer with double characteristics of rubber and plastic.In present paper,tanδ-T curve and hysteresis loss(HL) were chosen to characterize its damping property.The results indicated that its tanδvalue would increase with rising of temperature when T>0℃and form another damping peak at 40-80℃besides T_g peak.This phenomenon resulted from meltage of crystals of EU gum could increase its damping property at ambient-high temperature.Its tanδvalue even exceeded those of conventional damping rubbers,such as nitrile-butadiene rubber(NBR) and chlorinated isobutene-isoprene rubber(CIIR). 相似文献
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