粘土/炭黑/NR纳米复合材料的性能研究

在乳液插层法制备的粘土／NR纳米复合材料中加入炭黑，制得粘土／炭黑／NR纳米复合材料，并对其微观结构和性能进行研究。结果表明，炭黑的加入并没有影响粘土在NR基体中的分散状态，粘士炭黑和在NR基体中均达到纳米级分散；炭黑的加入削弱了粘土所形成填料网络的强度，从而改善了复合材料的加工性能；与粘土／NR纳米复合材料相比，粘土／炭黑／NR纳米复合材料的综合物理性能较好。     

凝聚共沉法改性高岭土/NR复合材料的性能研究

以浓缩NR胶乳为主体材料，改性高岭土为填料，用凝聚共沉法制备改性高岭土／NR复合材料，研究影响复合材料物理性能的因素，并对材料拉伸断裂面的形貌进行扫描电镜分析。结果表明，改性高岭土／NR复合材料具有优良的物理性能，且在拉伸过程中无应力发白现象；在改性剂乳酸钾溶液质量分数为0.05、高岭土改性温度为80℃以及改性高岭土用量为40份的条件下，制得的改性高岭土／NR复合材料物理性能最佳。     

粉煤灰纤维/NR复合材料的制备与性能研究

采用铝锆偶联剂对粉煤灰纤维进行预处理,制备粉煤灰纤维/NR复合材料,并对其性能进行研究。结果表明,采用铝锆偶联剂对粉煤灰纤维预处理能够改善纤维和橡胶基体界面的结合状况;粉煤灰纤维最佳用量为40份,可明显提高粉煤灰纤维/NR复合材料的物理性能和绝缘性能,但撕裂强度有所下降。     

硅烷偶联剂对蒙脱土/NR纳米复合材料气体阻隔性能的影响

试验研究硅烷偶联剂对蒙脱土（MMT）／NR纳米复合材料性能的影响。结果表明，在MMT／NR复合材料中加入硅烷偶联剂，可提高复合材料的物理性能、耐热空气老化性能、气体阻隔性能和热稳定性。硅烷偶联剂KH-560的改性效果最好，其最佳用量为3份。     

团状模塑料增强粉煤灰／再生胶复合材料研究

以再生胶为基相,粉煤灰为填料,团状模塑料（DMC）为增强相制备了高性能的复合材料。通过测定复合材料的力学性能及热老化性能,得出DMC／粉煤灰／再生胶复合材料的最佳配方为：DMC60,粉煤灰50,再生胶100。复合材料的综合性能优于纯的DMC和再生胶的性能。     

硅烷偶联剂对原位生成二氧化硅/NR复合材料性能的影响

研究硅烷偶联剂对原位生成二氧化硅粒子特征和原位生成二氧化硅／NR复合材料性能的影响。结果表明，在溶胶-凝胶反应中加入硅烷偶联剂，原位生成的二氧化硅粒子表面积减小，表面羟基减少，分散较好；在混炼过程中添加硅烷偶联剂，原位生成二氧化硅／NR复合材料的物理性能有明显提高，其中添加硅烷偶联剂A的复合材料物理性能、耐磨性能和耐疲劳性能较好；添加偶联剂Si75的复合材料耐磨性能较好。     

NR/有机蒙脱土/GMA纳米复合材料的制备与性能研究

采用胶乳接枝插层法制备NR／有机蒙脱土／甲基丙烯酸缩水甘油酯(GMA)纳米复合材料，并对其性能进行研究。结果表明，在NR胶乳与有机蒙脱土体系中加入GMA，并使之原位聚合，同时实现对NR的接枝和对有机蒙脱土的插层并与有机蒙脱土层间的基团产生化学结合，可以制备NR／有机蒙脱土／GMA纳米复合材料；采用胶乳接枝插层法制备的NR／有机蒙脱土／GMA纳米复合材料的物理性能和耐热氧老化性能优异，动态力学性能良好，热稳定性与NR胶料相差不大。     

碱活化改性高岭土/NR复合材料的结构和性能研究

采用凝聚共沉法制备碱活化改性高岭土／NR复合材料，并对其物理性能和微观结构进行研究。结果表明，高岭土改性时间为3d、改性高岭土与天然胶乳混合温度为45℃、改性高岭土用量为40份时，碱活化改性高岭土／NR复合材料的综合物理性能较好；改性高岭土在NR基体中发生了定向排列，基本上以面-面平行状态均匀分散，大部分高岭土以厚度为25-75nm的层叠形式平行分布在NR基体中；改性高岭土与NR基体间形成过渡层。     

ZDMA/NR复合材料的性能研究

以甲基丙烯酸锌（ZDMA）为补强剂,研究硫化剂DCP用量、ZDMA用量和硫化时间对ZDMA/NR复合材料物理性能的影响.结果表明,在硫化剂DCP存在的情况下,ZDMA对NR具有明显的补强作用,ZDMA/NR复合材料的物理性能和耐热空气老化性能明显改善;当ZDMA和硫化剂DCP的用量分别为15和1.5份、硫化时间为1.5t90时,ZDMA/NR复合材料具有较好的综合物理性能.     

紫炭黑/天然橡胶复合材料的制备及性能研究

以黄原胶为辅助剂,采用湿法制备紫炭黑/天然橡胶(NR)复合颗粒胶,研究了紫炭黑用量对紫炭黑/NR复合材料硫化特性、力学性能、加工性能和动态性能的影响。结果表明,紫炭黑/NR颗粒胶粒径大小均一,紫炭黑未渗出或散开,紫炭黑和天然胶乳共凝效果较好;紫炭黑的添加可以改善复合材料的物理性能,当紫炭黑用量为20份时,复合材料综合性能较好;橡胶加工分析(RPA)表明,紫炭黑的加入使复合材料的tanδ增加,弹性模量降低,加工性能得到改善。     

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.     

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.     

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.     

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.