NR/BR/TPI并用胶性能之研究

按照NR/BR/TPI并用胶90/10/0,85/10/5,80/10/10,75/10/15,70/10/20之不同配比,研究了TPI对并用混炼胶性能、硫化胶的力学性能、老化性能及其分散状态的影响。结果表明,当TPI含量为5份时,TPI与NR和BR相容性最好,硫化胶硫化网络结构均匀,交联网络达到了极大值,tanδ值较小,动态性能优异,NR/BR/TPI并用混炼胶性能优异。     

TPI和不同硫化体系下硫黄用量对TPI/NR/BR并用胶性能的影响

研究TPI和不同硫化体系下硫黄用量对TPI/NR/BR并用胶性能的影响,结果表明,TPI/NR/BR并用比为15/42.5/42.5、选用普通硫黄硫化体系且硫黄用量为2份时,TPI/NR/BR混炼胶的加工性能良好,硫化胶可达到物理性能、动态疲劳性能和耐热空气老化性能的平衡.     

用于全钢子午线轮胎胎侧胶的反式-1,4-聚异戊二烯/天然橡胶/顺丁橡胶并用胶的性能

研究了不同反式-1,4-聚异戊二烯(TPI)用量对用于全钢子午线轮胎胎侧胶的TPI/天然橡胶(NR)/顺丁橡胶(BR)并用胶力学性能、动态力学性能和热老化性能的影响,并对并用胶进行了配方优化。结果表明,当TPI/NR/BR的并用比(质量比)为15.0/42.5/42.5时,混炼胶外表光滑,硬度适中;TPI/NR/BR并用胶的硫化特性与NR/BR并用胶相比变化不大,且在保持后者力学性能的基础上,动态力学性能明显提高;经配方优化后,并用胶耐屈挠性优异,滚动阻力、压缩生热降低,是一种较为理想的全钢子午线轮胎胎侧胶材料。     

NR/TPI并用胶性能的研究

研究了反式-1,4-聚异戊二烯（TPI）用量对天然橡胶（NR）/TPI硫化胶力学性能和动态性能的影响。结果表明,NR/TPI并用比为80/20时,硫化胶在保持常规力学性能的基础上,动态疲劳性能显著提高,生热降低。采用溶液法合成的TPI与NR并用后,并用胶动态疲劳性能进一步提高。     

TPI/NR/BR并用胶的性能与应用

研究了不同反式-1,4-聚异戊二烯(TPI)用量及补强与填充体系对TPI/天然橡胶(NR)/顺丁橡胶(BR)并用胶力学性能、动态性能和热老化性能的影响。结果表明,当TPI/NR/BR的质量比为15.0/42.5/42.5时,混炼胶外表光滑,硬度适中;硫化胶的硫化特性变化不大,在保持基本配方硫化胶力学性能的基础上,动态力学性能明显提高。当加入4~8份白炭黑时,并用胶的撕裂强度、定伸应力提高,滚动阻力、压缩生热降低,是一种较理想的全钢子午线轮胎胎侧胶配方。     

TPI/NR并用胶在全钢子午胎胎肩垫胶中的应用

研究了不同反式-1,4-聚异戊二烯(TPI)用量对TPI/NR并用胶力学性能和动态性能的影响,并对TPI/NR并用胶进行配方优化。结果表明,TPI/NR并用比为15/85时,混炼胶胶片光滑,硫化胶在保持基本配方的力学性能的基础上,压缩生热性能明显提高,伸张疲劳系数有所提高;经优化配方后,TPI/NR混炼胶的粘合强度提高,硬度适中,利于后续半成品的加工,且硫化胶具有低生热性,滚动阻力降低,是一种较为理想的全钢子午线轮胎胎肩垫胶配合。     

溶液法反式-1,4-聚异戊二烯/天然橡胶共混胶的性能

研究了用负载钛催化剂、通过溶液聚合法合成的高纯度反式-1,4-聚异戊二烯(TPI)与天然橡胶(NR)共混胶的硫化特性、力学性能、老化性能以及动态疲劳性能。结果表明,与NR相比,TPI与NR质量比为20/80共混胶的门尼黏度稍高,硫化特性基本相当,力学性能略有下降,而其动态疲劳性能则提高至NR的3~4倍。当硫黄与促进剂M的质量比为2.5/1.0时,TPI/NR共混胶的综合性能达到最佳。     

杜仲胶/天然橡胶/顺丁橡胶并用胶的工艺研究

用杜仲胶(TPI)替代部分天然橡胶(NR),并与顺丁橡胶(BR)共混生产出混炼胶,研究了TPI/NR/ BR共混硫化胶料制备过程中,硫化温度、硫化时间、硫化剂的用量、硫化促进剂的种类及用量对胶料物理机械性能的影响。研究结果表明,硫化过程中当硫化温度为150℃、硫化时间为20 min、硫化剂为硫黄(质量不超过3份)和硫化促进剂的含量为2份时,胶料的综合物理机械性能较好。     

高抗疲劳性轿车轮胎胎侧胶的配方设计与性能研究

研究反式-1,4-丁二烯-异戊二烯共聚橡胶(TBIR)的结晶性能、加工性能以及NR/BR/TBIR并用胶在轿车轮胎胎侧胶中的应用。结果表明:相比反式-1,4-聚异戊二烯(TPI),TBIR的结晶性能微弱、玻璃化温度更低;相比天然橡胶(NR)和顺丁橡胶(BR),TBIR具有优异的加工性能;相比NR,BR和TPI,TBIR的耐老化性能优异;相比NR/BR和NR/BR/TPI并用胶,NR/BR/TBIR(并用比为45/35/20)并用胶的物理性能优异,生热降低,耐裂口扩展性能显著提高。TBIR作为一种新型合成橡胶材料可应用于高耐疲劳轿车轮胎。     

新型异戊橡胶用量对并用胶性能的影响

新型异戊橡胶(TPIR)既保持了反式-1,4-聚异戊二烯(TPI)滚动阻力小、压缩生热低、耐疲劳性能优异的特点,又大大改善了它的耐屈挠龟裂产生性能和耐裂口增长性能,预计是发展高性能轮胎的理想胶料。本文初步研究了TPIR用量对TPIR/NR/BR并用胶在硫化特性、物理机械性能、动态性能、老化性能的影响,以及TPIR并用胶与TPI并用胶性能对比。     

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.