超支化分散剂对聚丙烯/玻璃纤维/硅灰石复合材料性能的影响

通过改变超支化分散剂DZHA-17在聚丙烯/玻璃纤维/硅灰石复合材料中的用量,考察了分散剂对复合材料加工性能、力学性能、表观性能以及分散性的影响。结果表明:随着分散剂用量的增加,复合材料的加工性能、力学性能、表观性能和分散性明显提高。当分散剂用量为1份时,复合材料的熔体流动速率提高了3.5倍,挤出机扭矩和电流分别降低到6.5 N·m和36 A,断裂伸长率、缺口冲击强度和60°光泽度也明显提高。聚丙烯/玻璃纤维/硅灰石复合材料的力学性能、表观性能与其微观结构息息相关。     

聚硫橡胶/环氧树脂/棕刚玉弹性砂轮的研制

研究聚硫橡胶/环氧树脂／棕刚玉三元共混体系对金属的高精度磨蚀机理。研制的聚硫橡胶／环氧树脂／棕刚玉弹性砂轮对金属的磨光粗糙度可达Ra=0．8μm。采用0．5～0．6份分散剂研制的弹性砂轮,能够达到Ra=1．0μm以下的高精度磨光要求。对异型精密仪器的磨光工效是手工磨光的8～10倍。     

环氧树脂/蛭石纳米复合材料的制备与表征

以环氧树脂为基体,二甲基苄胺为固化剂,经酸浸、加热和钠离子交换的结构修饰和有机改性的蛭石为增强剂,制备了环氧树脂/蛭石纳米复合材料.测试了环氧树脂/蛭石纳米复合材料的结构、形貌、力学和电学性能.结果表明:环氧树脂、二甲基苄胺和蛭石的混合顺序,二甲基苄胺和蛭石的用量影响蛭石的剥离,进而影响环氧树脂/蛭石纳米复合材料的性能.在蛭石加入量为环氧树脂质量的1%～5%范围内,3%时环氧树脂/蛭石纳米复合材料的抗拉强度、弹性模量和弯曲强度最大,表面电阻最低,体电阻最高.     

分散剂B-52对白炭黑/天然橡胶复合材料性能的影响

通过机械共混法制备白炭黑/天然橡胶(NR)复合材料,研究分散剂B-52用量对白炭黑/NR复合材料性能的影响。结果表明:随着分散剂B-52用量的增大,复合材料的t_(10)和t_(90)呈现出先延长后缩短的趋势,结合胶含量和表观交联密度提高,综合物理性能先提高后有所降低;当分散剂B-52用量为2份时,复合材料的综合物理性能最佳。     

不同粒径氮化硼填充环氧树脂/玻璃纤维

以聚砜改性环氧树脂为基体,通过高温模压制备了环氧树脂/玻璃纤维/氮化硼复合材料,研究了不同粒径及不同氮化硼导热粒子用量对复合材料导热性能、力学性能和电性能的影响。结果表明,大粒径粒子有利于复合材料力学性能的提高,小粒径有利于导热性能的提高;随着氮化硼用量的增加,复合材料的导热性能升高,力学性能呈现先增后降趋势,当氮化硼用量为10 %（质量分数,下同）时,复合材料的冲击强度和弯曲强度均达到最佳,当氮化硼用量为20 %时,复合材料仍保持较好的电性能。     

RA-g-PHS超分散剂对PP/MCF木塑复合材料性能的影响

采用自制松香海松酸接枝聚十二羟基硬脂酸(RA-g-PHS)超分散剂改性聚丙烯(PP)/剑麻纤维素微晶(MCF)木塑复合材料,研究了RA-g-PHS超分散剂用量对PP/MCF木塑复合材料力学性能、熔体流动速率和热性能的影响,并用扫描电子显微镜（SEM）对PP/MCF木塑复合材料冲击断面形貌的微观结构进行分析。结果表明,当RA-g-PHS超分散剂用量为2 %时,PP/MCF木塑复合材料的冲击强度为13.68 kJ/m2,熔体流动速率为2.06 g/10 min,相比未添加RA-g-PHS超分散剂的PP/MCF木塑复合材料分别提升了100 %和34.6 %,且热稳定性最好。     

环氧树脂改性MC尼龙/碳纤维/二硫化钼复合材料的研制

利用E-51环氧树脂(EP)改性MC尼龙,并以碳纤维(CF)粉为增强剂、二硫化钼(MoS2)为润滑剂、炭黑为增容剂,制备了MC尼龙复合材料.分别研究了EP,CF粉及MoS2的用量对MC尼龙复合材料性能的影响,并测试了MC尼龙复合材料与钢及铝合金摩擦时的耐磨损性能.结果表明,当MC尼龙用量为100份、EP为1.5份、CF粉为13份、MoS2为6.5份、炭黑为3.5份时,MC尼龙复合材料具有较好的力学性能和摩擦性能.相对于钢,该MC尼龙复合材料与铝合金摩擦时的耐磨损性能较好.     

粘土/天然橡胶复合材料的制备与性能研究

采用分散剂多聚脂肪酸盐水杨酰亚胺制备粘土/天然橡胶(NR)复合材料,并对其性能进行研究。结果表明:当水杨酰亚胺用量为0.015份、粘土用量为50份、不添加偶联剂或环氧化天然橡胶时,所制得的粘土/NR复合材料具有优异的拉伸性能、抗撕裂性能、耐磨性能以及较低的压缩生热;粘土在NR基体中均匀分散。     

偶联剂对凹凸棒土/三元乙丙橡胶复合材料性能的影响

研究偶联剂品种和用量对凹凸棒土（AT）/三元乙丙橡胶（EPDM）复合材料性能的影响。结果表明：与未用偶联剂改性的AT/EPDM复合材料相比,偶联剂改性的AT/EPDM复合材料物理性能明显提高;采用偶联剂Si69改性的AT/EPDM复合材料物理性能最好;偶联剂Si69用量为1份时,AT用量为50份的AT/EPDM复合材料物理性能较好。     

隔声阻尼丁腈橡胶/氯丁橡胶复合材料的 制备及性能研究

以丁腈橡胶（NBR）和氯丁橡胶（CR）为主体材料,通过添加云母粉、中空玻璃微珠（HGB）、蒙脱土（MMT）制备隔声阻尼NBR/CR复合材料,并利用正交试验研究NBR/CR并用比、云母粉用量、HGB用量、MMT用量对NBR/CR复合材料阻尼性能和隔声性能的影响,确定NBR/CR复合材料的优化配方组合。结果表明：对于NBR/CR复合材料的最大损耗因子（tanδ_max）,其影响因素的主次顺序为NBR/CR并用比、HGB用量、云母粉用量、MMT用量;对于NBR/CR复合材料的有效阻尼温域宽度,其影响因素的主次顺序为NBR/CR并用比、云母粉用量、MMT用量、HGB用量;对于NBR/CR复合材料的平均隔声量,其影响因素的主次顺序为HGB用量、云母粉用量、MMT用量、NBR/CR并用比;NBR/CR复合材料的优化配方组合为：NBR/CR并用比　70/30,云母粉用量　10份,HGB用量　12份,MMT用量　10份。     

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.