共查询到19条相似文献,搜索用时 62 毫秒
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以聚硼硅氮烷(PSNB)、N-乙烯基吡咯烷酮(NVP)为原料,由过氧化二异丙苯(DCP)引发自由基共聚合反应,制备了聚硼硅氮烷(PSNB/NVP)杂化树脂。采用差示扫描量热仪、热失重仪、红外光谱仪、平板流变仪等对杂化树脂的热性能、固化过程、流变行为等进行测试。结果表明,随着PSNB与NVP的质量比的提高,杂化树脂的热稳定性升高,PSNB与NVP质量比为20/80的杂化树脂在热质量损失率达到为5%时的温度较聚N-乙烯基吡咯烷酮提高近200℃;由杂化树脂高温裂解可得到硅硼碳氮多孔陶瓷,其孔尺寸及分布极不均匀。 相似文献
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对甲基乙烯基二氯硅烷(MeViSiCl2)进行氨解形成聚甲基乙烯基硅氮烷(PMVS),进而用二甲基硫醚硼烷(BH3-SMe2)和PMVS进行硼氢化反应,合成出SiBCN陶瓷的前驱体聚硼硅氮烷(polyborosilazane,PBSZ)。Fourier红外光谱分析表明:合成的PBSZ中有C-B-C和Si-N特征吸收峰,分别对应HC-B(CH)-CH和≡Si-NH-基团;11B和29Si的核磁共振分析产物中有BC3,SiN2C2,SiN3C和SiC3N等结构单元,这些光谱结果表明合成的产物为PBSZ。对PBSZ热压成型,在1000℃氩气中热解制备出SiBCN陶瓷体。PBSZ的热重分析表明:氩气中1300℃热解的陶瓷产率为52.6%。陶瓷局部致密,表明用前驱体热解法有望获得致密的SiBCN陶瓷体。 相似文献
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以四氯化硅、三氯化硼、甲胺为原料,使用共缩聚方法制备了SiBNC陶瓷纤维前驱体聚硅硼氮烷。采用FT-IR、NMR、GC-MS和TG分析等,对聚硅硼氮烷的结构、性能和合成机理进行了表征和分析。研究表明该聚硅硼氮烷前驱体的骨架结构由Si-N-B和B-N六元环结构组成,C则主要以N-CH_3和NH-CH_3结构存在。合成得到的前驱体具有良好的溶解性、耐水解性能和可纺性,在105℃的N_2气氛下,经熔融纺丝可得直径约为25μm的前驱体原丝,在N_2气氛中1 000℃时陶瓷产率为60%。 相似文献
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Gwomei Wu Li-Hang Hsieh How-Wen Chien 《International journal of molecular sciences》2013,14(11):21319-21327
Novel birefringent liquid crystal polymer homeotropic films have been coated on semiconductor solar cells to improve the effective incident sunlight angles. The liquid crystal polymer precursor, based on reactive mesogens, is fluidic and flows like liquid. It would distribute uniformly on the solar cell sample surface by any traditional coating technique. The birefringence for light, due to the liquid crystal retardation properties, manipulated the optical length and the deflection of incident light, thus allowed an increase in the energy conversion efficiency. The expensive sunlight tracking systems could be avoided. The processing parameters can be tuned such as different mesogen concentrations and plate speeds of spin-coating. The results showed that the solar cell conversion efficiency was improved from 14.56% to 14.85% at an incident sunlight angle of 15°. It was further improved from 13.40% to 13.81% when the angle was 30°. The interesting angular dependency on solar cell efficiency enhancement has been evaluated. 相似文献
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一种侧链型液晶高分子气相色谱固定液的合成及应用 总被引:1,自引:0,他引:1
通过合成的4-(4′-辛氧基-苯甲酰氧基-4-苯甲酰氧基)-苯基丙烯酸酯与苯乙烯在一定条件下聚合得到一种聚合物。采用广角X-射线衍射仪、热重分析仪和差示扫描量热计表征了合成聚合物的结构及热性能。该液晶聚合物为固定液制成色谱柱,对几组混和物进行分离,效果良好。该液晶聚合物固定液使用温度为100~220℃。 相似文献
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Ye Gao Jean’ne M. Shreeve 《Journal of Inorganic and Organometallic Polymers and Materials》2007,17(1):19-36
This article is one of a number of reviews in a special issue to honor Prof. Dr. Ian Manners of the University of Bristol,
UK, for his outstanding contributions in the field of organometallic polymers. The focus of this review is on the syntheses,
properties, and characterization of ferrocene-containing liquid crystalline polymers in which ferrocene moieties are in or
pendent to the backbone and also dendrimers and [60]fullerene-ferrocene liquid crystalline materials. 相似文献
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采用液相法,以含氢聚硅氧烷和乙烯基环四硅氧烷为前驱体,经注模、交联和热解制备出净成型的硅氧碳陶瓷体,研究了该体系的成型、交联和热解行为,以及高温热解过程中陶瓷结构和组成的转变。研究表明:该体系有很好的成型能力,以不同材质和形状的模具均可成型,经热解可制备出各种形状和尺寸的硅氧碳陶瓷材料;交联体在整个热解过程中均保持完整,可获得不同温度(400~1 000 ℃ )的无开裂的热解体;硅氧碳陶瓷在高温热解过程中通过 Si—O 和 Si—C 键重排由无定形的 Si—O—C 网络转化为含 SiC 和 SiO2纳米晶的陶瓷结构 相似文献
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Two Canadian peats from Quebec were pyrolyzed using the Waterloo Fast Pyrolysis Process (WFPP) technology with the objective of maximizing liquid yields. A young sphagnum peat (Sogovex) gave maximum yields of organic-liquids (moisture free basis) of 45% to 47% in an optimum range of 450° to 550°C at atmospheric pressure. Char yields decreased from 35% to 26% and gas yields increased from 12% to 17% over this range. The character of the liquid product changed significantly over the optimum temperature range, with the ratio of water-soluble to water-insoluble components decreasing from 2.3 to 0.6, with an accompanying decrease in oxygen content. Pyrolysis tests using an old black peat (Premier) gave similar results, although with some what lower yields of organic liquids and higher char yields. Upgrading tests on the peat oil done under hydrodeoxygenation conditions in collaboration with Battelle PNWL resulted in a yield of about 33% of the liquid feed as a gasoline-like liquid. 相似文献
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以疏水改性碳黑颗粒为污染源,以纯棉布、纯涤布和涤棉混纺布为实验对象,建立了抗再沉积性能快速实验方法,并在标准洗衣液的基础上,研究了洗涤环境因素、聚合物类型对抗污渍再沉积效果的影响.结果表明:洗涤溶液pH、浓度对抗再沉积性基本无影响,洗涤溶液硬度、温度和电导率的升高会导致体系抗再沉积能力下降;从抗再沉积剂看,聚酯聚醚聚合... 相似文献
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生物质热化学转化制液体燃料的研究进展 总被引:4,自引:1,他引:3
生物质是唯一可转化成可替代常规液态石油燃料和其它化学品的可再生碳资源。热化学高效转化利用技术是生物质能源开发利用的最主要途径。本文综述了国内外生物质热化学转化制备液体燃料技术的主要研究途径、产业化进程的现状,论述了生物质液体燃料的产业化发展的可能性和存在的问题。对中国生物质热化学转化的发展趋势提出了研究开发利用的发展前景和建议。 相似文献