橡胶操作油用量对溶聚丁苯橡胶性能的影响

研究在溶聚丁苯橡胶（SSBR）和白炭黑配方体系中,橡胶操作油（简称操作油）用量对胶料性能的影响。结果表明：随着操作油用量的增大,胶料的门尼粘度、F_L和F_max减小,t₅和t₉₀延长;硫化胶的邵尔A型硬度、定伸应力和拉伸强度减小,拉断伸长率、撕裂强度和回弹值增大,耐磨性能和抗切割性能下降,弹性模量和粘性模量减小,0和70 ℃时的损耗因子变化不大,玻璃化温度（T_g）降低。SSBR胶料的门尼粘度、焦烧时间和转矩以及硫化胶的邵尔A型硬度、定伸应力、拉断伸长率、回弹值和T_g均与操作油用量之间具有高度线性相关性。     

不溶性硫黄对轮胎带束层胶料与镀铜钢丝帘线动态粘合性能的影响

研究不溶性硫黄对轮胎带束层胶料与镀铜钢丝帘线（简称镀铜钢丝）动态粘合性能的影响。结果表明：随着不溶性硫黄用量的增大，胶料的门尼焦烧时间t₅逐渐缩短，t₉₀－t₁₀逐渐延长、门尼粘度、 F_L.和F_max逐渐增大；硫化胶的邵尔A型硬度增大，定伸应力增大，拉伸强度和拉断伸长率逐渐减小；静态和动态疲劳后胶料与镀铜钢丝的粘合抽出力均呈先增大后减小的趋势，抽出界面镀铜钢丝的裸露面积先减小后增大，覆胶体积先增大后减小。     

杜仲橡胶在全钢载重子午线轮胎胎面胶中的应用

在全钢载重子午线轮胎胎面胶中直接添加5～15份杜仲橡胶或用杜仲橡胶等量替代天然橡胶（NR）,研究其对胎面胶性能的影响。结果表明：在胎面胶中直接添加杜仲橡胶,胶料的门尼粘度增大,门尼焦烧时间略有延长;且随着杜仲橡胶用量的增大,t₉₀略有延长,Fmax－FL呈减小趋势,硫化胶的邵尔A型硬度、100%定伸应力和300%定伸应力呈减小趋势,抗切割指数先减小后增大,拉伸强度和回弹值变化不大,拉断伸长率呈增大趋势,胶料0和25 ℃时的损耗因子（tanδ）先增大后减小,但均大于未添加杜仲橡胶的胶料,60 ℃时的tanδ变化不大;将杜仲橡胶等量替代NR,随着杜仲橡胶用量的增大,胶料的门尼粘度呈增大趋势,t₉₀基本呈延长趋势,F_max－F_L先增大后减小,硫化胶的硬度、100%定伸应力、300%定伸应力呈减小趋势,拉断伸长率、回弹值、DIN磨耗指数和抗切割指数呈增大趋势,拉伸强度变化较小,胶料0 ℃时的tanδ增大,60 ℃时的tanδ减小,表明胶料的抗湿滑性能提高,滚动阻力下降。     

液体1，4-聚丁二烯在丁苯橡胶胶料中的应用

研究液体1,4-聚丁二烯（LPB）在丁苯橡胶胶料中的应用。结果表明：LPB的微观结构主要为顺式-1,4-结构和反式-1,4-结构;采用LPB作为增塑剂替代环保芳烃油（TDAE）,胶料的 t₁₀和t₉₀延长,硫化胶的耐磨性能提高,滚动阻力降低,但同时抗湿滑性能下降;以LPB等量替代TDAE,硫化胶的拉伸性能下降,以LPB部分替代TDAE,硫化胶的拉伸性能提高。     

氧化石墨烯/炭黑/乳聚丁苯橡胶纳米复合材料的性能研究

利用乳液插层复合法制备氧化石墨烯/乳聚丁苯橡胶（ESBR）复合胶,研究其在工程机械轮胎胎面胶中的应用。结果表明：在胎面胶中加入氧化石墨烯,氧化石墨烯/炭黑/ESBR纳米复合材料的t₉₀延长;剪切储能模量和储能模量增大,玻璃化温度变化不大,损耗因子峰值减小;主要物理性能和耐磨性能提高。     

反式聚辛烯橡胶在轮胎内衬层胶中的应用

研究反式聚辛烯橡胶（TOR）在轮胎内衬层胶中的应用。结果表明：随着TOR用量的增大,胶料的t_s1和 t₁₀先延长后缩短,但均长于未添加TOR的胶料, t₉₀呈逐渐延长趋势;添加4份TOR后,胶料的包辊性明显改善;添加TOR后,硫化胶的邵尔A型硬度变化不大,拉伸强度有所降低,拉断伸长率和撕裂强度明显提高,气密性变化不大,耐屈挠性能提高;添加5份TOR的内衬层的挺性和抗塌性提高,保证了半成品的尺寸稳定性,有利于加工。     

氧化锌减量对内燃机车用二系橡胶堆性能的影响

研究氧化锌减量对内燃机车用二系橡胶堆胶料性能和成品耐疲劳性能的影响。结果表明：氧化锌用量从5份减到3份,胶料的t₁₀和t₉₀缩短,硬度、定伸应力、拉伸强度及压缩永久变形基本不变,撕裂强度增大,压缩疲劳温升降低,屈挠龟裂性能改善;成品橡胶堆的垂向刚度及剪切刚度略微减小,疲劳试验后的垂向变形、垂向刚度变化率、剪切刚度变化率减小,温升降低,耐疲劳性能提高。     

反式聚辛烯橡胶/丁腈橡胶并用胶的性能研究

研究反式聚辛烯橡胶（TOR）/丁腈橡胶（NBR）并用比对并用胶性能的影响。结果表明：随着TOR用量的增大,胶料的加工性能提高,焦烧时间变化不大,t₉₀延长,硫化胶的邵尔A型硬度和100%定伸应力增大,拉伸强度、拉断伸长率和回弹值总体减小,耐磨性能、耐3^#标准油性能和耐低温性能下降;TOR/NBR硫化胶的玻璃化温度升高,低温下的储能模量、损耗模量和损耗因子减小。     

液体聚异戊二烯橡胶对天然橡胶/反式聚异戊二烯橡胶并用胶性能的影响

研究液体聚异戊二烯橡胶（LIR-50）用量对未填充和填充填料的天然橡胶（NR）/反式聚异戊二烯橡胶（TPI）（并用比85/15）并用胶硫化特性、结晶性、物理性能和动态力学性能的影响。结果表明：NR/TPI并用胶的t₁₀和t₉₀随着LIR-50用量的增大而延长,且加工流动性变好;在NR/TPI并用胶中TPI的结晶受到抑制,LIR-50用量对NR/TPI并用胶的结晶性影响不大;随着LIR-50用量的增大,NR/TPI并用胶的邵尔A型硬度、300%定伸应力、拉伸强度及储能模量减小;加入3份LIR-50的并用胶的撕裂强度最大、综合物理性能较好;LIR-50加入对NR/TPI并用胶的耐磨性能、抗湿滑性能以及滚动阻力基本无影响。     

耐低温超低压缩永久变形三元乙丙橡胶的配方设计

研究由乙烯、丁烯和亚乙基降冰片烯为单体,茂金属催化合成的新型三元乙丙橡胶（EBT EPDM）和通用三元乙丙橡胶（EPDM）的耐低温性能以及炭黑种类对EBT EPDM胶料耐低温性能的影响。结果表明：与EPDM胶料相比,EBT EPDM胶料的t₁₀和t₉₀均缩短,F_max－F_L增大;EBT EPDM硫化胶在低温条件（－40 ℃×72 h）下的压缩永久变形减小了71.5%,脆性温度降低了37.7%,低温回缩温度TR10最低,低温弯曲后表面未出现裂纹,耐低温性能优异;随着炭黑粒径的增大,EBT EPDM硫化胶的低温压缩永久变形减小,脆性温度降低;在相同低温条件下,EBT EPDM硫化胶的压缩永久变形与硅橡胶硫化胶相近,但EBT EPDM价格远低于硅橡胶,可拓宽其在低温密封领域的应用。     

Polymorphism of LiGa5O8 and of LiGa5O8-MgGa2O4Solid Solutions

High-temperature X-ray diffraction and differential thermal analyses showed that LiGa₅O₈ exists in two polymorphs related by the first-order transition at 1138°±3°C of the low-temperature simple-cubic form, space group (probably) O⁷, to the high-temperature spinel (fcc) form, space group O _h ⁷. The transition is rapid, and the high-temperature form in pure LiGa₅O₈ could not be quenched to room temperature under the conditions used. However, the high-temperature polymorph can be quenched under equilibrium conditions when 40 mol% or more MgGa₂O₄ is present. The subsolidus equilibrium relations in the system MgGa₂O₄-LiGa₅O₈ are discussed.     

Magnetoresistance of CuxCo1-xFe2O4 Ferrites

Magnetoresistance measurements (Δ/R) were carried out on Cu _x Co_{1- x} Fe₂O₄ samples with x =1, 0.75, 0.50, 0.25 and cobalt ferrite in the range of magnetic intensity (H) from 1.0 to 4.5 kG. Linear plots were obtained between log (Δ/R) and log H for all compositions except that of cobalt ferrite. The values of n at x =0.5 do not agree with the results of some authors. The discrepancy may be attributed to the value of magnetic field intensity at which such measurements were carried out. The similarity of features of n and μ_D with composition leads us to believe that the magnetoresistance may arise from the scattering of conduction electrons by localized electrons involving the s-d exchange interaction.     

Sintering of Si3N4-Y2O3-Al2O3

Sintering kinetics of the system Si₃N4-Y2O₃-Al₂O3 were determined from measurements of the linear shrinkage of pressed disks sintered isothermally at 1500° to 1700°C. Amorphous and crystalline Si₃N₄ were studied with additions of 4 to 17 wt% Y₂O₃ and 4 wt% A1₂O₃. Sintering occurs by a liquid-phase mechanism in which the kinetics exhibit the three stages predicted by Kingery's model. However, the rates during the second stage of the process are higher for all compositions than predicted by the model. X-ray data show the presence of several transient phases which, with sufficient heating, disappear leaving mixtures of β ' -Si₃N₄ and glass or β '-Si₃N₄, α '-Si₃N₄, and glass. The compositions and amounts of the residual glassy phases are estimated.     

Expansive properties of the mixture C4ASH12 − 2CS III. Effects of temperature and restraint

The effects of temperature and restraint upon the hydration and the expansion of $\text{C}{}_4\text{A}\text{S}\text{H}{}_{12}\text{? 2}\text{C}\text{S}$ mixture compacts in different contact solutions have been investigated. Temperatures above 20°C do apparently hinder the formation of an impervious felt-like layer of ettringite around the $\text{C}{}_4\text{A}\text{S}\text{H}{}_{12}$ particles, thus greatly reducing the retarding effect of the lime. An uniaxial restraint of 1 Kg/cm² is enough to reduce sensibly the expansions which remain however high (about 100%). The results can be satisfactorily interpreted by the reaction and expansion mechanism hypothesized in our previous papers.     

Raman Study of Glasses of Ba2TiSi2O8 and Ba2TiGe2O8

Raman spectra are reported for fresnoite (Ba₂Ti(Si,Ge)₂O₈ glasses, and comparison is made between the Raman spectra of the corresponding crystalline powders and glasses of Ba₂TiSi₂O₈ and Ba₂TiGe₂O₈. The Ba₂TiGe₂O₈ glass spectra show correspondence with the Ba₂TiGe₂O₈ crystalline Raman spectra; the v _s(Ge–O–Ge) mode occurs at 518 cm⁻¹ in the glass and at 521 cm⁻¹ in the crystalline material. Five-fold coordinated titanium is the majority species present in the Ba₂TiGe₂O₈ glass as revealed by a strong band at 824 cm⁻¹ in the I glass spectrum. The Ba₂TiSi₂O₈ glass spectra are similar to the Ba₂TiSi₂O₈ crystalline spectrum; the strongest band is found at 836 cm⁻¹ in the I glass spectrum. Through comparison with the previous Raman data of other titania silicate glasses, we conclude that the Ba₂TiSi₂O₈ glass has a structure similar to the crystalline phase.     

Preparation and properties of poly(Nε,Nε-dicarboxymethyl-l-lysine)

A new ampholytic homopolypeptide, $\text{poly}\text{(N}{}^{\mathrm{\epsilon }}\text{,N}{}^{\mathrm{\epsilon }}\text{-}\text{dicarboxy-methyl-}\text{l}\text{-lysine}\text{)}$, which has one tertiary amino and two carboxyl groups in the side chain has been derived from a hydrochloride salt of poly(L-lysine). The polymer in aqueous solution seems to be in the coil form with locally extended structure (LES) at neutral pH. In both the acidic and alkaline regions, the molar ellipticity of the polymer changes as a result of change in net charge on the side chain. The conformational changes may be from the coil with LES to other coiled forms. 5–7 M NaClO₄ and 80% aqueous methanol induce the α-helix in the polymer at neutral pH. Divalent cations, Cu²⁺ and Ca²⁺, do not induce any remarkably ordered structures such as α-helix or β-structure in the polymer in aqueous solution at any pH. Ultraviolet absorption studies show an absorption peak of the polymer-Cu²⁺ complex near 240 nm. Dependence of the peak intensity on pH at various q values ($\text{q =}\text{[}\text{Cu}{}^{\mathrm{2+}}\text{]}\text{[}\text{residue}\text{]}$) indicates the two steps of the complex formation. At q less than 0.64, the formation is described only with the first step. An average coordination number for Cu²⁺ at the first step was calculated to be about 2 by the method of Mandel and Leyte. The association constant of Cu²⁺ with the residue at the step was determined from the absorption data to be far smaller than that for the Cu²⁺-EDTA complex. The second step of the formation occurs in the case of large q but the absorption data for the second step cannot be obtained exactly due to precipitation.     

Effects of metal-support interactions on the hydrogenation of CO over PdSiO2 and PdLa2O3

A study of CO hydrogenation over $\text{Pd}\text{SiO}{}_2$ and $\text{Pd}\text{La}{}_2\text{O}{}_3$ has been carried out for the purpose of identifying the effects of Pd dispersion, Pd morphology, and support composition on the catalytic activity of supported Pd. The specific activity of each catalyst for methanol and methane synthesis was determined from microreactor studies carried out at a fixed set of reaction conditions. Palladium dispersion was measured by H₂O₂ titration, and the morphology of the Pd crystallites, as expressed by the distribution of Pd(100) and Pd(111) planes, was determined from in situ infrared spectra of adsorbed CO. The crystallite morphology of the $\text{Pd}\text{SiO}{}_2$ catalysts is the same, independent of Pd weight loading: 90% of the surface is comprised of Pd(100) planes and 10% of the surface is comprised of Pd(111) planes. By contrast, the crystallite morphology of the $\text{Pd}\text{La}{}_2\text{O}{}_3$ catalysts changes with Pd loading. Primarily Pd(100) planes are exposed at low-weight loadings while Pd(111) planes are exposed at high-weight loadings. The Pd dispersion has little effect on the methanol turnover frequency over both $\text{Pd}\text{SiO}{}_2$ and $\text{Pd}\text{La}{}_2\text{O}{}_3$, for dispersions between 10 and 20%. On the other hand, the methane turnover frequency is independent of Pd dispersion over $\text{Pd}\text{SiO}{}_2$, but increases with decreasing dispersion over $\text{Pd}\text{La}{}_2\text{O}{}_3$. It is further observed that the Pd morphology influences the specific activity of $\text{Pd}\text{La}{}_2\text{O}{}_3$ for methanol synthesis: Pd(100) is nearly threefold more active than Pd(111). For a fixed morphology, the specific methanol synthesis activity of $\text{Pd}\text{La}{}_2\text{O}{}_3$ is a factor of 7.5 greater than that of $\text{Pd}\text{SiO}{}_2$.     

In situ laser raman spectroscopy of the sulfiding of Moγ-Al2O3 catalysts

Raman spectra of sulfided $\text{Mo}\text{γ-}\text{Al}{}_2\text{O}{}_3$ catalysts were obtained using in situ techniques for two sulfiding methods. For samples sulfided by 10% $\text{H}{}_2\text{S}\text{H}{}_2$ at 400 °C, MoS₂ structures were observed. A stepwise sulfiding using 10% $\text{H}{}_2\text{S}\text{H}{}_2$, with spectra recorded at 150, 250, and 350 °C, resulted in observation of molybdenum oxysulfide, reduced molybdate, and surface “MoS₂” phases. Reexposure of these samples to air led to radical modification of the oxysulfide structures as well as transformation of some sulfide phases. A model incorporating terminal and bridging MoS bonding and anion vacancies is proposed. This model is based on the conversion of isolated and aggregated molybdate and MoO₃ species to oxysulfide and reduced molybdenum phases. Conversion of reduced molybdenum phases to sulfides is observed to be slow.     

Wet Milling of Fe/Al/Al2O3 and Fe2O3/Al/Al2O3 Powder Mixtures

Wet milling of Al₂O₃-aluminide alloy (3A) precursor powders in acetone has been investigated by milling Fe/Al/Al₂O₃ and Fe₂O₃/Al/Al₂O₃ powder mixtures. The influence of the milling process on the physical and chemical properties of the milled powders has been studied. Particle refinement and homogenization were found not to play a dominant role, whereas plastic deformation of the metal particles leads to the formation of dislocations and a highly disarranged polycrystalline structure. Although no chemical reactions among the powder components in Fe₂O₃/Al/Al₂O₃ powder mixtures were observed, the formation of a nanocrystalline, ordered intermetallic FeAl phase in Fe/Al/Al₂O₃ powder mixtures caused by mechanical alloying was detected. Chemical reactions of Fe and Al particle surfaces with the atmosphere and the milling media lead to the formation of highly porous hydroxides on the particle surfaces. Hence the specific surface area of the powders increases, while the powder density decreases during milling. The fraction of Fe oxidized during milling was determined to be 0.13. The fraction of Al oxidized during milling strongly depends on the metal content of the powder mixture. It ranges between 0.4 and 0.8.