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三元乙丙橡胶/乙烯-辛烯共聚物/甲基乙烯基硅橡胶共混物的制备与性能 总被引:2,自引:0,他引:2
用动态硫化法制备了乙烯-辛烯共聚物(POE)/甲基乙烯基硅橡胶(MVQ)热塑性弹性体(PMTPV),进而将其与三元乙丙橡胶(EPDM)共混制备EPDM/POE/MVQ三元共混物(EPDM/PMTPV)。对高温开炼机、转矩流变仪、双螺杆挤出机3种工艺制备的PMTPV进行了性能对比,研究了EPDM/PMTPV的共混比对胶料性能的影响。结果表明,双螺杆挤出机制备PMTPV的综合性能最好;随着PMTPV用量的增加,EPDM/PMTPV共混胶的力学性能、绝缘性、耐寒性、耐热性及耐油性得以改善。扫描电镜分析结果也说明在EPDM/PMTPV体系中,EPDM与MVQ的相容性比在EPDM/MVQ直接共混体系中有了较大程度的提高。 相似文献
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采用Haake转矩流变仪制备了乙烯-辛烯共聚物(POE)/硅橡胶(MVQ)动态硫化热塑性弹性体(TPV),考察了共混温度、转速、动态硫化时间对POE/MVQ共混物硫化特性、TPV物理机械性能及加工特性的影响,观察了硫化剂不同投料方式下TPV的外观形貌。结果表明,在共混温度为130℃、转速为50~60 r/min、动态硫化时间约为8 min的条件下,采用POE与MVQ混匀后分3批加入硫化剂的方式,所得POE/MVQ TPV的综合性能较好,表面光滑且有韧性。 相似文献
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低硬度POE/PP动态硫化胶的制备与性能研究 总被引:2,自引:0,他引:2
采用动态硫化法制备了POE/PP热塑性弹性体,运用正交设计方法系统研究了POE/PP树脂类型及用量比、交联剂类型及用量、助交联剂类型及用量、加工工艺条件等对POE/PP动态硫化胶性能的影响规律。结果表明,POE/PP用量比、加工工艺和捏合温度是影响材料性能的关键因素;当POE/PP用量比为70/30、捏合温度为240℃时,所得低硬度POE/PP共混型热塑性弹性体的性能最佳,其拉伸强度为4.54MPa,断裂伸长率可迭1023%,且加工流动性远优于EPDM/PP型动态硫化胶。 相似文献
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以纯度为40%的双叔丁基过氧化二异丙基苯为交联剂、异氰尿酸三烯丙酯为助交联剂,研究了动态硫化的温度和转速对于聚烯烃弹性体/聚丙烯(POE/PP)共混物的性能以及异氰尿酸三烯丙酯的用量对于POE/PP共混物的性能和转矩的影响。结果表明,POE/PP共混物的拉伸强度、扯断伸长率和300%定伸应力都随动态硫化温度的升高而先增大后减小,撕裂强度随动态硫化温度的升高而减小,动态硫化温度为180℃时的总体力学性能较好;随着动态硫化转速的提高,POE/PP共混物的拉伸强度和300%定伸应力都先增大后减小,扯断伸长率减小,撕裂强度则增大,动态硫化的转速为50 r/min时共混物的总体力学性能较好。助交联剂异氰尿酸三烯丙酯的加入明显提高了POE/PP共混物动态硫化时的转矩,其用量以1份(质量)为宜。 相似文献
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采用一步法挤出工艺制备了硅烷交联聚丙烯/聚烯烃弹性体(PP/POE)共混材料。研究了乙烯基三甲氧基硅烷(VTMS)含量对硅烷交联PP/POE共混材料凝胶含量、热稳定性、结晶行为和力学性能的影响。结果表明:硅烷交联结构能够有效提升PP和POE相之间的相容性。随着VTMS含量的增加,硅烷交联PP/POE共混材料的凝胶含量和热稳定性呈上升趋势,而共混材料中PP相的结晶度却逐渐减小。力学测试表明,过氧化二异丙苯(DCP)在引发硅烷接枝反应的同时也会使PP发生降解。随着VTMS含量的增加,硅烷交联PP/POE共混材料的拉伸强度逐渐增大,断裂伸长率及缺口冲击强度则均呈先升后降趋势。 相似文献
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A new ampholytic homopolypeptide, , 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 () 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. 相似文献
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Silvia Schicker Daniel E. García Igor Gorlov Rolf Janssen Nils Claussen 《Journal of the American Ceramic Society》1999,82(10):2607-2612
Wet milling of Al2 O3 -aluminide alloy (3A) precursor powders in acetone has been investigated by milling Fe/Al/Al2 O3 and Fe2 O3 /Al/Al2 O3 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 Fe2 O3 /Al/Al2 O3 powder mixtures were observed, the formation of a nanocrystalline, ordered intermetallic FeAl phase in Fe/Al/Al2 O3 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. 相似文献
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Sintering kinetics of the system Si3 N4-Y2O3 -Al2 O3 were determined from measurements of the linear shrinkage of pressed disks sintered isothermally at 1500° to 1700°C. Amorphous and crystalline Si3 N4 were studied with additions of 4 to 17 wt% Y2 O3 and 4 wt% A12 O3 . 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 ' -Si3 N4 and glass or β '-Si3 N4 , α '-Si3 N4 , and glass. The compositions and amounts of the residual glassy phases are estimated. 相似文献
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Akira Akimoto 《Polymer》1974,15(4):216-218
The polymerization of vinyl chloride has been investigated using an 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. 相似文献
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Mats Carlsson Mats Johnsson Mats Nygren 《Journal of the American Ceramic Society》1999,82(8):1969-1976
Ta0.33 Ti0.33 Nb0.33 C and Ta0.33 Ti0.33 Nb0.33 C x N1− 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 , Ta2 O5 , Nb2 O5 , 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. 相似文献