共查询到19条相似文献,搜索用时 140 毫秒
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中央空调通风系统用铝箔/MPF泡沫复合板的研制 总被引:1,自引:0,他引:1
用三聚氰胺改性酚醛发泡树脂,研制成功中央空调通风系统用铝箔/改性酚醛(MPF)泡沫复合板。铝箔/MPF泡沫复合板较铝箔/酚醛(PF)泡沫复合板各项性能都有提高,采用的连续湿法生产工艺可同步完成发泡、固化、覆铝箔过程。该复合板绝热耐用、质轻节能、美观清洁、气密隔音、耐火防水,具有广阔的市场前景。 相似文献
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《工程塑料应用》2020,(5)
利用生物质单宁取代部分苯酚,定量尿素作为甲醛捕捉剂,制备了单宁改性可发泡酚醛树脂,然后以硫酸与对甲苯磺酸混合酸作为固化剂,正戊烷为发泡剂,制备了单宁改性酚醛泡沫。利用傅里叶变换红外光谱和核磁共振氢谱对树脂结构进行了表征,依据GB/T 30694–2014检测了不同单宁用量对酚醛泡沫甲醛释放量的影响,使用电子万能试验机和极限氧指数(LOI)仪检测了不同单宁用量对酚醛泡沫力学性能和阻燃性能的影响。结果表明,改性酚醛泡沫pH为6;当加入的单宁用量为苯酚质量的3%时,改性酚醛泡沫甲醛释放量最低为1.1875 mg/L,达到了人造板E1标准,泡沫压缩强度为0.2166 MPa,冲击强度为2.81 kJ/m~2,粉化率低至2.01%,LOI达到37%,其综合性能最好。相对于纯酚醛泡沫,单宁改性酚醛泡沫的力学性能有所提升,脆性明显改善,阻燃性能显著提高。 相似文献
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《工程塑料应用》2014,(12):131-132
<正>一种纳米改性酚醛泡沫保温板及其制备方法公开号:CN104072941A公开日:2014-10-01申请人:锦州市好为尔保温材料有限公司摘要:本发明涉及一种纳米改性酚醛泡沫保温板及其制备方法,纳米改性酚醛泡沫保温板包括下述质量份的原料:酚醛树脂50~65份;反应性聚酰胺树脂20~25份;气相二氧化硅2~8份;液体丁腈橡胶5~15份;改性表面活性剂4~8.5份;韧性改性剂9~18份;发泡剂4~10份;固化剂6~8份;催化促进剂1~5.5份。制备时先进行原料混合;在均匀搅拌上述原料同时填加固化剂和催化促进剂,使其充分均匀混合;将发泡混合料放置于板材连续生产线上,使温度保持在 相似文献
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《Journal of the European Ceramic Society》2022,42(5):2408-2419
The in-situ mullite (3Al2O3·2SiO2) foams are fabricated by 3D printing (direct ink writing (DIW)) technique and utilize waste rice husk ash (RHA). The Al2O3-SiO2 inks are prepared using an aqueous binder with α-alumina and two different silica sources, i.e., RHA extracted biogenic nano-silica (NS) and commercial silica (CS). The ink rheological features are first designed in terms of solid-to-liquid ratio and dispersant, and found that a higher amount of dispersant is needed for functionalization of NS-containing ink than CS (micro-sized) consisting of ink. Secondly, the DIW log-pile structures are fired at different temperatures (1200?1500 °C), and NS containing samples exhibited remarkable enhanced properties at a lower firing temperature than CS. At 1400 °C, alumina and RHA nano-silica entirely transformed into mullite and retained ~75 % porosity, ~8 MPa cold compressive strength, and thermal conductivity ~0.173 W/m·k that designate a simple and effective way to fabricate of mullite foamy structure. 相似文献
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Xuanyu Meng Jie Xu Jiatong Zhu Zhuolun Li Jia Zhao Michael J. Reece Feng Gao 《Journal of the American Ceramic Society》2020,103(11):6088-6095
Lanthanum zirconate (LZO) ceramic foams with hierarchical pore structure were fabricated by particle-stabilized foaming method for the first time, and the as-prepared ceramics have high porosity of 90.7%-94.9%, low thermal conductivity, and relatively high compressive strength. The LZO powder was synthesized by solid-state method. The porosity of the ceramic foams was tailored by suspensions with different solid loadings (20-40 wt%). The sample with porosity of 94.9% has thermal conductivity of 0.073 W/(m·K) and compressive strength of 1.19 MPa, which exhibits outstanding property of thermal insulation and mechanical performance, indicating that LZO ceramic foam is a promising thermal insulation material in high temperature applications. 相似文献
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Xiaoxiao Li Shujing Li Yuanbing Li Shiqi Li Pan Chen Tenglong Guo 《International Journal of Applied Ceramic Technology》2023,20(6):3565-3575
In this study, ammonium phosphate monobasic and boric acid were used as the primary starting materials to produce BPO4 powder by solid-state reaction. Using BPO4 powders as the main raw material, BPO4 ceramic foams were prepared for the first time using the direct foaming method and freeze-drying techniques. The effects of the additive content and solid loading on the slurry's rheological behavior were investigated, and the microstructures and properties of the as-prepared BPO4 ceramic foams were examined. The results reveal that the porosity of the BPO4 ceramic foams synthesized at 1223 K ranged from 84.2% to 90.4%, the compressive strength ranged from .12 MPa to .72 MPa, and the thermal conductivity ranged from .32 W/(m·K) to .74 W/(m·K) (298 K). The findings of this study have great significance for the development of new thermal insulation ceramic materials. 相似文献
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Xuanyu Meng Jie Xu Jiatong Zhu Jia Zhao Mingyue Wei Runwu Yang Feng Gao 《Journal of the European Ceramic Society》2021,41(12):6010-6017
The potentially useful role of lanthanum zirconate (La2Zr2O7, LZO) porous bulk ceramics has been rarely explored thus far, much less the optimisation of its pore structure. In this study, LZO porous ceramics were successfully fabricated using a tert-butyl alcohol (TBA)-based gelcasting method, and the pore structures were tailored by varying the initial solid loading of the slurry. The as-prepared ceramics exhibited an interconnected pore structure with high porosity (67.9 %–84.2 %), low thermal conductivity (0.083–0.207 W/(m·K)), and relatively high compressive strength (1.56–7.89 MPa). The LZO porous ceramics with porosity of 84.2 % showed thermal conductivity as low as 0.083 W/(m·K) at room temperature and 0.141 W/(m·K) at 1200 °C, which is much lower than the counterparts fabricated from particle-stabilized foams owing to its unique pore structure with a smaller size, exhibiting better thermal insulating performance. 相似文献
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本文以环戊烷发泡硬质聚氨酯泡沫为研究对象,采用薄片室温老化原理连续测量两种密度样品165天长期导热系数,发现导热系数的升高呈现2个阶段。通过对所得曲线进行函数拟合发现导热系数变化符合对数关系,对数方程求解初步得到25年后50mm制品的导热系数。考虑到制样过程中无法避免样品表面发生开孔,最后对函数计算得到的数据进行修正,修正结果显示两种密度样品的长期导热系数均不超过0.029 W(m•K)-1。 相似文献
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The aim of this study was to investigate polyurethane foams (PUF) properties obtained from crude glycerol (CG) and polyethylene glycol (PEG) based liquefaction of sawdust. The four types of foam were prepared by producing polyols from different weight loadings of PEG to CG as the liquefaction solvent. The produced polyurethane foams showed densities from 0.042 to 0.08 g/cm3 and compressive strengths from 200 to 311 kPa. The foams obtained from CG/PEG based liquefaction, had more uniform and regular cell structure than foams derived from liquefaction by CG. Also with the increasing percentage of PEG to CG in liquefaction, closed cell content of the synthesized foams increased and the size of cells decreased. The thermal conductivity of the produced foams was between 0.031 and 0.040 W/m K. Foams produced from liquefaction by binary solvent had lower thermal conductivity. However all foams showed approximately similar thermal degradation curves; maximum thermal decomposition temperature was seen for the foam produced from higher weight ratio of PEG to CG in liquefaction. PU foams produced from PEG/CG based liquefaction process had improved properties over from foams derived from sawdust liquefaction by CG. 相似文献
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In the present work, poly(vinyl formal) (PVF) foams were prepared using water as the pore-forming agent and formaldehyde as the crosslinking agent. The acetalization process of poly(vinyl alcohol) was exploited in depth in order to obtain a precise guidance on the preparation of PVF foams with adjustable properties. With the increasing of formaldehyde, the crosslinking degree was gradually increased and the prepared PVF foams changed to be amorphous. Morphology observation showed that the porous structure of PVF foams was successfully created using water as the blowing agent and it was strongly affected by the crosslinking agent and polymer concentration, leading to an easily tuned pore size from hundreds of microns to few microns. The prepared foams were proved to have small apparent density below 0.27 g/cm−3 and excellent mechanical strength, with the largest specific compressive strength of 11.54 MPa·cm3·g−1. Based on the results, it is believed that this study can provide a scientific basis for the design and optimization of PVF foams with controllable structure and properties. 相似文献
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《Journal of the European Ceramic Society》2022,42(2):420-431
In this study, silicon carbide (SiC) composites reinforced with pitch-based carbon fibers and composed of heat transfer channels were fabricated by combining chemical vapor infiltration and reactive melting infiltration method. It was observed that the internal heat conduction skeleton of pitch-based carbon fibers was sequentially formed. The thermal conductivities from room temperature to 500 °C along through-thickness direction and in-plane direction were investigated. The results showed that Cpf/SiC composites with heat transfer channels possessed excellent thermal conductvity in two directions, and the thermal conductivity increased with increasing volume content of heat transfer channels. The thermal conductivity in through-thickness direction reached 38.89 W/(m·K), and that for in-plane direction reached 112.42 W/(m·K). Theoretical calculations were empolyed to study the temperature dependence of the Cpf/SiC composites. The variations in slope A′ and intercept B′ values of fitted curves were in good agreement with the experimental results. To verify the reliablilty of the theoretical model, the Cpf/SiC composites were heated at 1650 °C for 2 h and the thermal conductivity exhibited further improvement due to the formation of more perfect crystalline structure. Thermal conductivity through thickness direction improved to 43.49 W/(m·K), and that in in-plane direction improved to 142.49 W/(m·K), which could be identified by the theoretical model. Finally, the leading edge model was established by using ABAQUS finite element analysis software to evaluate the potential application of the composites. Owing to the outstanding thermal conductivity, the leading edge obtained by using Cpf/SiC composites in this study exhibited lower temperature gradient and a more uniform temperature distribution. Moreover, less thermal stress and displacement were generated during heating process. 相似文献
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《Ceramics International》2022,48(15):21561-21570
In this study, municipal solid waste incineration fly ash (MSWI FA) was used as a new raw material for the ceramics industry and a novel ultra-low thermal conductivity calcium silicate-based foams (CSFs) was prepared by the direct foaming method. The effects of the addition of foam and borax on the sintering behavior and microstructural evolution of the CSFs were investigated. With the optimal amount of foam, the CSFs had an apparent porosity of 63.43%–67.49%, bulk density of 0.75–0.84 g/cm3, compressive strength of 1.83–3.21 MPa, and room-temperature thermal conductivity of 0.213–0.235 W/(m·K). Notably, the whisker morphology, pore structure, and sintering behavior of the samples can be controlled by changing the amount of borax. The prepared ceramic foams can be applied in the fields of thermal insulation, filtration, and catalyst carriers. 相似文献