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增韧聚丙烯三元共混体阻燃性能的研究 总被引:3,自引:0,他引:3
研究了多种阻燃剂,包括Sb2O3、Al(OH)3、CPC、DBDPO对聚丙烯/高密度聚乙烯/乙丙橡胶(PP/HDPE/EPR)三元共混体—增韧聚丙烯—阻燃性能的影响;阻燃剂间的协同作用;并探讨了阻燃机理。结果表明:1、AL(OH)3的重量含量超过40%时,阻燃效果显著;2、三种阻燃剂(Sb2O3、DBDPO、CPE)并用,阻燃效果明显提高,含卤化合物(DBDPO与CPE)是Sb2O3重量的四倍时,阻燃性能最佳;3、Sb2O3与DBDPO并用时,当Br/Sb的摩尔比为3∶1时阻燃效果最好 相似文献
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A comparison of fatigue crack growth performance of two aerospace grade aluminium alloys reinforced with bonded crack retarders
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A.K. Syed X. Zhang M.E. Fitzpatrick 《Fatigue & Fracture of Engineering Materials & Structures》2018,41(5):1237-1242
To improve the fail‐safety performance of integral metallic structures, the bonded crack retarder concept has been developed in recent years. This paper presents an experimental investigation on the effectiveness of bonded crack retarder on fatigue crack growth life in two aerospace aluminium alloys: 2624‐T351 and 7085‐T7651. M(T) specimens bonded with a pair of straps made of GLARE fibre‐metal laminate were tested under the constant amplitude load. Although the bonded crack retarders increased the crack growth life in both alloys, the magnitude of life improvement is very different between them. Compared to unreinforced specimens, application of crack retarders has resulted in 90% increase in fatigue life in AA7085, but only 27% increase in AA2624. The significant difference in fatigue life improvement is owing to the material's intrinsic fatigue crack growth rate property, ie, the Paris law constants C and n. Value of n for AA7085 is 1.8 times higher than that for AA2624. Therefore, AA7085 is much more sensitive to reductions in the effective stress intensity factor brought by the crack retarders, hence better life improvement. 相似文献
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Kunal Kupwade-Patil Peter J. Boul Diana K. Rasner Saul H. Lapidus Juscelino B. Leao Kenneth D. Johnson Carl J. Thaemlitz Oral Büyüköztürk 《Journal of the American Ceramic Society》2020,103(11):6400-6413
The effect of a high-performance retarding additive in oil well cements was investigated under elevated temperature (165°C) and pressure (1000 psi) conditions via in situ synchrotron-based X-ray diffraction (XRD) and quasielastic neutron scattering (QENS) techniques. Under these temperature and pressure conditions, crystalline calcium silicate hydrates (C–S–H) are formed through the cement hydration process. From in situ XRD experiments, the retardation effect was observed by a change in the rate of the appearance of 11 Å tobermorites as well as a change in the rate of the α-C2SH generation and depletion. QENS analysis revealed that the retardation effect was related to the non-conversion of free water to chemical and constrained water components. A high presence of free water components was attributed to a decrease in 11 Å tobermorites along with slower consumption of the quartz and portlandite phases. Furthermore, QENS results infer that the water molecules experienced confinement in the restricted pore spaces. The retarder inhibited this initial water confinement by slowing the bulk diffusion of free water in the confined region. 相似文献
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缓凝剂与高效减水剂对水泥水化性能的影响 总被引:1,自引:0,他引:1
系统地研究了葡萄糖酸钠与三种高效减水剂复合对水泥水化性能的影响,结果表明:与空白水泥相比,缓凝剂与高效减水剂无论是单掺还是复合使用,对水泥的水化及其水化产物均有不同程度的影响;缓凝剂与高效减水剂复合后的协同效应与单掺缓凝剂、单掺高效减水剂时温峰出现时间有关. 相似文献
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Fail-safe design of integral metallic aircraft structures reinforced by bonded crack retarders 总被引:1,自引:0,他引:1
This paper presents an investigation on the effectiveness of crack growth retarders bonded to integral metallic structures. The study was performed by both numerical modelling and experimental tests. It focuses on aluminium alloy panels reinforced by bonded straps made of carbon-epoxy, glass-epoxy composite materials or a titanium alloy. The goal was to develop a fail-safe design for integrally stiffened skin-stringer panels applicable to aircraft wing structures. The modelling strategy and finite element models are presented and discussed. The requirements that the models should meet are also discussed. The study has focused on establishing the extent of crack retarder benefits, in terms of fatigue crack growth life improvement, by numerical simulation and experimental tests of various crack retarders. The results of predicted fatigue crack growth retardation have been validated by tests of laboratory samples. This study concludes that by bonding discrete straps to an integral structure, the fatigue crack growth life can be significantly improved. 相似文献
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Hubert Seiberle Carsten Benecke Thomas Bachels 《Journal of the Society for Information Display》2004,12(1):87-92
Abstract— Photo‐alignment of anisotropic optical thin films enables realization of novel optical elements, which were not feasible up until now. Photo‐aligned anisotropic thin films can be applied to rigid or flexible substrates, which may be flat or curved. The optical performance of such films can be tailored to application‐specific requirements by introducing tilt profiles of the optical axis and/or generate patterned retarders with continuous or periodical in‐plane variation of the optical axis. 相似文献