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991.
992.
贮存稳定的EVA/SBS复合改性沥青的性能研究 总被引:1,自引:0,他引:1
利用乙烯-醋酸乙烯酯无规共聚物(EVA)与苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)对沥青进行复合改性并对其进行动态硫化处理,测试了动态硫化前后试样的针入度、软化点、5℃延度、贮存稳定性等常规性能.并利用应变控制流变仪与光学显微镜对试样做了动态力学性能分析和相形态观察。通过对动态硫化前后试样性能变化的分析比较,结果表明:动态硫化后,试样的低温性能良好,而且由于试样内部弹性交联网络的形成,使试样的高温物理机械性能及高温贮存稳定性均获得了提高,降低了试样的温度敏感性。 相似文献
993.
报道[Ni(H2O)6](ClO4)2·2H2O的合成、晶体结构,单核镍(Ⅱ)配合物[Ni(IDB)2][C6H4(OH)COO]·ClO4·CH3CH2OH·H2O[配体IDB为N,N 二(2 苯并咪唑亚甲基)胺]的电化学性质,探讨标题配合物催化尿素水解的机理。X射线单晶衍射表明,[Ni(H2O)6](ClO4)2·2H2O晶体属单斜晶系,P2(1)/C空间群,化学式:Cl2H16O16Ni,Mr=401.74,晶胞参数:a=0.62383(12)nm,b=1.2464(3)nm,c=0.91845(18)nm,α=90°,β=106.93(3)°,γ=90°,V=0.6832(2)nm3,Z=2,F(000)=412,S=1.079,DC=1.953g/cm3,μ=1.890mm-1。最终因子R[I>2σ(I)]:R1=0.0423,wR2=0.1155;R(全部数据)∶R1=0.0506,wR2=0.1180。结构分析表明,[Ni(H2O)6](ClO4)2·2H2O的镍(Ⅱ)分别与6个H2O配位形成对称的正八面体构型。循环伏安实验说明,标题配合物在DMF溶液中在E1/2=0.884V处经历了一个准可逆的一电子氧化还原过程。 相似文献
994.
Blends of uncrosslinked styrene-butadiene rubber (SBR) with a terpene tackifier resin or a naphthenic oil have been characterized, and their autohesion and cohesion determined using a T-peel geometry. SBR/oil blends are homogeneous at all proportions, while SBR/resin blends, based on DSC and DMA analysis, undergo bulk phase separation at about 50% resin. However, migration of tackifier to the surface region is proposed at much lower resin contents. Compositions diluted with oil have autohesion similar to the neat SBR. This is attributed to compensating effects; although oil hastens self-bond formation by increasing chain mobility, this is nearly equally balanced by more facile chain separation during bond rupture. In short, oil-diluted compositions are soft and weak. On the other hand, SBR compositions containing small amounts of resin have high autohesion. Resin-diluted specimens deform easily at low strain, just as those containing oil, but intertwined chains of the former have greater resistance to separation, due at least in part to higher glass transition temperatures. It is proposed that autohesion is further enhanced by migration of tackifier to the surface. This causes SBR/resin compositions to be both soft and strong-a necessary condition for high autohesion. 相似文献
995.
996.
A novel aromatic amine organo‐modifier synthesized in our previous work was used to treat montmorillonite (MMT) and the organo‐modified MMT was used to prepare poly(etherimide) (PEI)/MMT nanocomposites by a melt intercalation method. MMT treated by this amine exhibited large layer‐to‐layer spacing and a high ion‐exchange ratio (>95%). The nanocomposites were characterized with X‐ray diffraction (XRD), transmission electron microscopy (TEM), dynamic mechanical analysis, a universal tester, thermogravimetric analysis, and by differential scanning calorimetry. The results of XRD and TEM showed that the nanocomposites formed exfoliated structures even when the MMT content was 10 wt %. When the MMT content was below 3 wt %, the PEI/MMT nanocomposites were strengthened and toughened at the same time. The nanocomposites also showed marked decreases in coefficient of thermal expansion and solvent uptake. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1857–1863, 2003 相似文献
997.
以植物还原剂——金银花提取物和化学还原剂——丙三醇,分别还原硝酸银,制备了两种纳米银溶液。采用浸渍法将上述制备的纳米银溶液分别对棉织物进行功能整理。利用SEM、EDS、XRD、FTIR分析整理前后棉织物的外观形貌及结构,并探讨了整理后的棉织物的抗紫外性能、不同洗涤次数后其含银量、色差和抗菌性能的变化。结果表明,纳米银粒子主要通过范德华力吸附在棉织物纤维素的无定形区;与化学还原法相比,植物还原法制备的纳米银粒径减小了约15nm,植物还原法制备的纳米银溶液整理后的棉织物经过50次洗涤后,棉织物表面的纳米银吸附量及色差变化不大,且对大肠杆菌和金黄色葡萄球菌的抑菌率仍旧达到99%以上,具有优异的抗菌性及良好的耐洗涤性能。另外,植物还原法制备的纳米银溶液整理后的棉织物紫外线防护系数(UPF)值达到了36.82,具有较好的抗紫外性能。 相似文献
998.
999.
Zhanwu Zhang Kai Way Li Wei Zhang Liang Ma Zhenguo Chen 《International Journal of Industrial Ergonomics》2014
A single arm pushing experiment was conducted in an electronic factory in Yantai, China to assess muscular fatigue using the theoretical models of muscular strength and maximum endurance time (MET) developed by Ma et al. (2009). Seventy seven workers, including 38 males and 39 females, participated in the study. The muscular strength of pushing was measured after the subject pushed a stick, with a force of 2.5 kgf, for 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 min. Fatigue rate was determined based on a regression approach. In addition to the theoretical model, the MET for such a pushing task was also determined using four empirical models in the literature. The results indicated that females were more resistant to muscular fatigue than males in the pushing task. The results of the muscular strength prediction show that the predictability of the muscular strength model is acceptable. The prediction errors for muscular strength for female subjects were significantly lower than those of the male subjects. The predicted MET using the theoretical model, with a group constant k, was highly correlated with those using the empirical models compared in the current study. 相似文献
1000.