白炭黑/炭黑复合填料对天然橡胶补强性能的研究

炭黑和白炭黑是橡胶主要的补强填料,可以显著提升橡胶的性能。虽然炭黑和白炭黑有各自的优势,但白炭黑/炭黑共用可以更好地提高天然橡胶(NR)的物理性能和动态性能。本工作用不同用量比的白炭黑/炭黑复合填料(用量50份)补强NR,考察胶料的拉伸强度、撕裂强度、耐磨性能、抗裂口增长性能、生热性能和滚动阻力等。结果表明,复合填料的白炭黑用量为20份和30份时NR胶料综合性能较好。     

炭黑/稻壳源白炭黑并用对天然橡胶增强作用的粒径效应

考察了不同粒径炭黑与稻壳源白炭黑并用对天然橡胶(NR)性能的影响。结果表明,随着炭黑粒径的增大,炭黑/稻壳源白炭黑增强NR混炼胶的门尼黏度、最低转矩及最高转矩均变小,加工性能变好。随着炭黑粒径的增大,炭黑/稻壳源白炭黑增强NR硫化胶的拉伸强度降低,邵尔A硬度减小,耐磨性能及耐老化性能变差。N 330与稻壳源白炭黑并用增强NR具有较好的耐寒性能和抗湿滑性能,较低的滚动阻力。     

星型嵌段结构集成橡胶在高性能轮胎胎面胶中的应用及性能研究

研究了炭黑和炭黑/白炭黑两种补强填充体系对集成橡胶(SIBR)/天然橡胶(NR)、SIBR/顺丁橡胶(BR)及SIBR/NR/BR胶料性能的影响。结果表明,共混比为70/30的SIBR/NR体系的综合性能最好,具有较好的拉伸性能和抗湿滑性能;炭黑/白炭黑补强体系的性能优于全炭黑补强体系,具有较高的物理机械性能,较好的耐屈挠、耐刺扎和低生热性能,其低滚动阻力性能与高抗湿滑性能之间具有良好的平衡。     

NR/BR/OMMT纳米复合材料的结构与性能研究及其在轮胎胎面胶中的应用

采用机械混炼法制备了天然橡胶/顺丁橡胶/有机蒙脱土(NR/BR/OMMT)纳米复合材料,并对复合材料的结构与性能进行了表征。OMMT可明显提高橡胶基体的耐油性能和物理机械性能,降低混炼胶的焦烧时间(Ts)和正硫化时间(T90),起到了促进硫化作用。轮胎胎面胶配合显示,OMMT与炭黑并用补强NR/BR共混胶,明显改善其力学性能与耐磨耗性能。     

顺丁橡胶和白炭黑对炭黑/天然橡胶复合材料性能的影响

试验研究顺丁橡胶(BR)和白炭黑对炭黑/天然橡胶(NR)复合材料性能的影响。结果表明:与炭黑/NR复合材料相比,炭黑/NR/BR胶料的焦烧时间略有缩短,交联程度增大,硫化胶的300%定伸应力增大,压缩生热降低,抗切割性能下降,耐磨性能提高,滚动阻力减小;炭黑/白炭黑/NR胶料的交联程度减小,硫化胶的拉断伸长率和撕裂强度明显增大,压缩生热略有升高,抗切割性能和耐磨性能提高,滚动阻力增大(须通过加入偶联剂予以改善)。     

炭黑、白炭黑加入顺序对NR/SSBR胶料性能的影响

通过改变炭黑、白炭黑的加料顺序,探讨了炭黑/白炭黑在不同并用比下（75/25,50/50）在天然橡胶（NR）与溶聚丁苯橡胶（SSBR）共混体系中的最佳加入顺序。结果表明,炭黑、白炭黑的加入顺序并不是绝对的,炭黑/白炭黑并用比为75/25时（填料总量为45份）,先加白炭黑有利于白炭黑的分散,硫化胶物理机械性能较好,压缩生热较低,动态力学性能较好;当炭黑/白炭黑并用比为50/50时,炭黑/白炭黑一起加入得到的硫化橡胶性能较好。     

白炭黑/炭黑复合填充对NR性能的影响

在白炭黑和炭黑填料总量一定的情况下,研究了不同白炭黑/炭黑配比对NR性能的影响。结果表明,白炭黑用量增加,NR硫化速率下降,体系中炭黑填料网络被破坏且白炭黑-橡胶间较弱的相互作用也会对NR硫化胶力学性能产生一系列影响。DMA结果表明,加入20~25份白炭黑对提高硫化胶的抗湿滑性和降低滚动阻力最为有效。     

白炭黑/炭黑/SBR复合材料的结构和抗静电性研究

采用高温共混技术制备白炭黑/炭黑/溶聚丁苯橡胶(SSBR)和白炭黑/炭黑/乳聚丁苯橡胶(ESBR)复合材料,并分别对其结构和性能进行研究.结果表明,在填充剂总量不变的前提下,随着白炭黑用量的增大,白炭黑/炭黑/SSBR和白炭黑/炭黑/ESBR复合材料物理性能呈现加和效应的特点,动态性能提高,表面电阻和体积电阻率增大;白炭黑/炭黑/SSBR复合材料物理性能与白炭黑/炭黑/ESBR复合材料差别较小,但前者动态性能较好;添加导电炭黑使复合材料抗静电性提高、物理性能下降;当白炭黑/炭黑并用比为35/35、导电炭黑用量不大于5份时,白炭黑/炭黑/SSBR复合材料的综合性能较好.     

用热胀离解探讨炭黑/白炭黑与天然橡胶的作用力

将炭黑DZ 13、N 330和N 660及改性的白炭黑TB2和通用白炭黑填充的天然橡胶(NR)在二甲苯中于不同温度下进行离解,外推其离解温度,并通过傅里叶变换红外光谱和热重分析等手段判断填料与橡胶分子链之间的界面结合强度。结果发现,利用溶剂溶胀法外推出的炭黑DZ 13/NR、炭黑N 330/NR和炭黑N 660/NR的结合胶完全离解温度分别为360,334,220℃,表明炭黑DZ 13与NR的化学结合力较强。虽然白炭黑/NR结合胶的离解曲线与炭黑结合胶有所不同,但其外推的完全离解温度均比炭黑低,说明改性白炭黑随着温度的升高,其表面的改性剂在溶剂中被逐渐溶解,从而造成了橡胶分子链的脱离。     

OMMT/NR纳米复合材料的性能研究

采用两种有机蒙脱土(OMMT)通过机械混炼法制备OMMT/NR纳米复合材科,并对复合材料的各项性能进行研究.结果表明,与NR相比,OMMT/NR纳米复合材料的加工性能、物理性能、热稳定性能和动态力学性能均有明显改善;以N,N'-二甲基-烷烃铵盐作为蒙脱土改性剂制备的OMMT/NR纳米复合材料的加工性能和物理性能较好.     

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.     

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.     

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.     

Participation of lewis base on vinyl chloride polymerization with Al(C2H5)3CCl4 catalyst system

The polymerization of vinyl chloride has been investigated using an $\text{Al}\text{(}\text{C}{}_2\text{H}{}_5\text{)}{}_3\text{CCl}{}_4$ catalyst system in the presence of various Lewis bases. Effective Lewis bases are γ-butyrolactone, diglyme and diethylenetriamine which are multidentate. The rate of polymerization is dependent not only on the basicity of the Lewis base used but also on a coordination number of one. The latter is the predominant factor. For the effect of polymeric amines, a tentative hypothesis is discussed.     

Synthesis and Characterization of Ti0.33Ta0.33Nb0.33C and Ti0.33Ta0.33Nb0.33CxN1-x Whiskers

Ta_0.33Ti_0.33Nb_0.33C and Ta_0.33Ti_0.33Nb_0.33C _x N_{1− x} whiskers were synthesized via a carbothermal vapor-liquid-solid growth mechanism in the temperature range 900°-1450°C in Ar or N₂. The optimum temperature was 1250°C. Whiskers were obtained in a yield of 70-90 vol%. The whiskers were 0.5–1 µm in diameter and 10–30 µm in length. The starting materials that produced the highest whisker yield were: TiO₂, Ta₂O₅, Nb₂O₅, C, Ni, and NaCl. C was added to reduce the oxides, and Ni to catalyze whisker growth. NaCl was used as a source of Cl for vapor-phase transportation of Ta and Nb oxochlorides and Ti chlorides to the catalyst. The catalyst metal was recycled several times during the synthesis and was transported as NiCl₂( g ) according to thermodynamic calculations. The rate of formation and the chemical composition of the whiskers depended on the synthesis temperature, the choice of catalyst, and the atmosphere. At low temperatures, the whiskers were enriched in Nb and Ta, whereas the Ti content increased with increased synthesis temperature.