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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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氮化硼纤维先驱体聚合物的合成及其表征 总被引:3,自引:0,他引:3
以三氯化硼与氯化铵为基础原料合成了三氯环硼氮烷(TCB),然后将TCB和三氯化硼分别与甲胺反应制得TCB的衍生物(CH3NH)3N3B3H3和B(NHCH3)3单体,将这些衍生物混合后在一定条件下进行缩合反应得到氮化硼先驱体。从合成方法、反应机理及其产物的结构性能表征等方面研究了氮化硼陶瓷纤维的先驱体,并且用IR、NMR、EA.XRD及DSC等表征方法对先驱体的结构、成分及性能进行了分析。结果表明:先驱体中含有B、C、N、H元素,存在CH3、B-N、N—H、G—H、BN六元环等结构单元。最后,对此先驱体进行了试纺丝,并用扫描电镜观察了所得纤维的形态。 相似文献
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《合成纤维工业》2017,(2)
以三氯化硼、六甲基二硅氮烷、三氯硅烷和甲胺为原料,采用多步法合成、聚合得到可纺性良好的聚硼氮硅烷(PBSZ)前驱体,通过熔融纺丝得到前驱体纤维,再经热化学交联得到不熔化纤维;在氨气/氮气(NH_3/N_2)气氛下进行热解脱碳(C)处理制备了硅硼氮(SiBN)陶瓷纤维;研究了NH_3/N_2体积比、气体流量、升温速率、保温时间以及热解温度等对SiBN纤维中C含量的影响,分析了PBSZ的脱C机理。结果表明:较优的热解工艺是NH_3/N_2体积比为3∶1,升温速率为0.5℃/min,600℃和1 000℃分别保温3 h,气体流量为100 m L/min,可制备C质量分数小于0.1%的Si BN陶瓷纤维;NH3对脱C具有积极作用,在热交联反应、自由基反应和脱氢偶合反应的综合作用下,C主要以甲胺和甲烷的形式脱除。 相似文献
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以氰酸酯为基胶,聚硼硅氮烷前驱体为固化剂,复配相应的填料,制备了氰酸酯基耐高温胶粘剂。研究了聚硼硅氮烷用量对氰酸酯固化特性、固化产物的结构变化及固化物热稳定性的影响。研究结果表明:与传统的氰酸酯胶粘剂相比,聚硼硅氮烷催化氰酸酯的固化温度降低了50~100℃;聚硼硅氮烷可以催化氰酸酯在150℃低温固化,20份聚硼硅氮烷催化氰酸酯固化物T5%最高达到476.3℃。以此为基础制备的耐高温胶粘剂的室温粘接强度最高为16 MPa,400℃老化3 h后粘接强度仍达到12 MPa,表明该胶粘剂具有较好的粘接性能和耐老化性能。本研究制备的胶粘剂凭借较低的固化温度、良好的粘接性能和耐温性,有望用于航空、航天和电子等行业。 相似文献
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介绍了含硅西佛碱的合成,制备了8种含硅西佛碱。用^1H—NMR、^13C—NMR对合成的化合物进行表征。目标分子为Ph—CH=NCH2CH2CH2Si(OCH2CH3)3;Ph—CH=NCH2CH2NHCH2CH2CH2Si(OCH2CH3)3;o-HO-Ph—CH—NCH2CH2CH2Si(OCH2CH3)3;o-HO-Ph—CH=NCH2CH2NHCH2CH2CH2Si(OCH2CH3)3;2,4-Cl-Ph—CH=NCH2CH2CH2Si(OCH2CH3)3;2,4-Cl-Ph-CH=NCH2CH2NHCH2CH2CH2Si(OCH2CH3)3;p-NO2-Ph-CH=NCH2CH2CH2Si(OCH2CH3)3;P-NO2-Ph-CH=NCH2CH2NHCH2CH2CH2Si(OCH2CH3)3。 相似文献
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A preceramic polymer for Si? B? N? C fiber, polyborosilazane, has been synthesized by one‐step condensation reaction of dichloromethylsilane, BCl3, and hexamethyldisilazane with high yield. The reaction mainly involves the condensation of Si? Cl and B? Cl with N? SiMe3 followed by SiMe3Cl evaporation and dehydrogenation between N? H and Si? H. The resulted polymer is a soluble colorless transparent solid with melting point of 70°C and molecular weight of 10,800. The backbone of the polymer is mainly composed of ? Si? N? B‐bridge with some borazine rings. The polymer exhibits good processability and flexible polymer fibers with diameter of 15–20 μm were obtained by melt spinning. Pyrolysis of the as‐synthesized polymer to 1000°C under nitrogen atmosphere results in a ceramic yield of 63 wt %, and the obtained Si? B? N? C ceramic remains fully amorphous up to 1700°C, and only small amount of poorly crystallized BN, Si3N4, and SiC phases were observed upon heating at 1850°C. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
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Scarlett Widgeon Gabriela Mera Yan Gao Sabyasachi Sen Alexandra Navrotsky Ralf Riedel 《Journal of the American Ceramic Society》2013,96(5):1651-1659
A comparative structural study of silicon borocarbonitride polymer‐derived ceramics synthesized using polyborosilylcarbodiimide and polyborosilazane precursors is carried out using high‐resolution, multinuclear, one‐ and two‐ dimensional NMR spectroscopy. The polyborosilylcarbodiimide‐derived ceramics contain relatively pure Si3N4 and C nanodomains with the BN domains being present predominantly at the interface such that the bonding at the interface consists of Si–N–B, Si–N–C, and B–N–C linkages. In contrast, the structure of the polyborosilazane‐derived ceramics consists of significant amount of mixed bonding in the nearest‐neighbor coordination environments of Si and B atoms leading to the formation of SiCxN4?x (0 ≤ x ≤ 4) tetrahedral units and BCN2 triangular units. The interfacial region between the SiCN and C nanodomains is occupied by the BCN phase. These results demonstrate that the chemistry of the polymeric precursors exerts major influence on the microstructure and bonding in their derived ceramics even when the final chemical compositions of the latter are similar. 相似文献
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《合成纤维》2015,(12):5-9
以实验室自制的三醋酸纤维素(CTA)为原料,研究其最佳水解条件及水解产物二醋酸纤维素(CDA)的可纺性能。结果表明:60℃下水解时间为4 h,H_2O与CTA的质量比为5∶1,催化剂H_2SO_4的质量分数为CTA的12%,可得到取代度为2.60的CDA。水解产物CDA经湿法纺丝后得到的纤维的干态断裂强度为1.45 c N/dtex,优于目前国内市售的CDA纤维。用FTIR、XRD、TG、SEM对CDA及其纤维进行分析表征,结果显示:CDA经水解和纺丝后结晶度会下降,CDA热分解温度低于CTA和纤维素;SEM照片显示CDA纤维表面有少许沟槽,断面呈圆形结构。 相似文献
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Hideto Tsuji Yoshito Ikada Suong-Hyu Hyon Yoshiharu Kimura Toshio Kitao 《应用聚合物科学杂志》1994,51(2):337-344
To obtain poly(lactic acid) (PLA) complex fibers, spinning was performed by wet and dry methods from 5–10 g/dL chloroform solutions of poly(D-lactic acid) (PDLA) and poly(L-lactic), both with a viscosity-average molecular weight of 3 × 105. The dope was extruded from a monohole nozzle into coagulation baths from ethanol and chloroform for wet spinning and into a drying column kept at 60°C for dry spinning. Scanning electron microscopic observation of the as-spun fibers showed that the surface of the wet-spun fiber had large basins with diameters of 50–100 μm and many pores with diameters from sub μm to 10 μm, whereas the surface of dry-spun fiber had a microporous structure with the pore diameter of 1–3 μm. The tensile strength of the wet-spun complex fiber was very low and could not be drawn at high temperatures, in contrast to the dry-spun fiber. The tensile strength of dry-spun complex fiber increased upon hot drawing and showed the tensile strength of 94 kg/mm2 by drawing at 160°C to the draw ratio of 13. Differential scanning calorimetry revealed that the complex fibers contained both the stereocomplex crystallites (racemic crystallites) and the crystallites of the single polymers, PDLA and PLLA, regardless of the spinning methods. The ratio of the racemic crystallites to the single-polymer crystallites increased with the draw ratio of the complex fiber. © 1994 John Wiley & Sons, Inc. 相似文献
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液态聚硼硅氮烷的陶瓷化过程 总被引:1,自引:0,他引:1
采用Fourier红外光谱、热重–差热以及X射线衍射分析对新型液态SiBNC先驱体进行了结构表征,重点研究了先驱体的陶瓷化过程。结果表明:先驱体以—CH3和—CH=CH2为侧链基团,含有C—H、C=C、Si—H、B—N、N—H、Si—N等化学键;N2气氛保护下的陶瓷产率约为85%,质量损失主要发生在300~800℃;随着温度的升高,聚合物中有机基团逐渐减少,900℃完成无机化转变,得到含有自由碳的非晶态SiBNC陶瓷,1200℃以上非晶态SiBNC陶瓷开始晶化,1500℃得到由C、SiC、Si3N4和BN组成的复相陶瓷。 相似文献
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《Ceramics International》2019,45(16):20172-20177
A novel polymeric precursor polyborosilazane (PBSZ) for SiBN ternary ceramic fibers was successfully synthesized from trichlorosilane (HSiCl3), boron trichloride (BCl3) and hexamethyldisilazane (HDMZ) by a simple one step reaction process. The chemical structures and ceramic yield of the PBSZ precursors were investigated by NMR spectroscopy, FT-IR and TGA. The preparation of PBSZ fibers was conducted in a lab-scale melt-spinning equipment at a spinning speed of 130 m/min. SiBN ternary ceramic fibers were obtained after the non-fusible treatment and pyrolysis of PBSZ fibers in an NH3 atmosphere. The pyrolysis mechanism, high-temperature behavior and morphologies of the SiBN ternary ceramic fibers were investigated by NMR, XRD, TEM and SEM. The obtained SiBN ternary ceramic fibers had good flexibility, and possessed a tensile strength of 0.84 GPa with a diameter of ∼18 μm. Furthermore, these SiBN ceramic fibers exhibited excellent thermal stability, and maintained the amorphous state up to 1600 °C. 相似文献
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提高1.33dtex缝纫线型涤纶短纤维强、伸度探讨 总被引:1,自引:0,他引:1
通过正交实验分析了纺速、拉伸倍率、DF3出口处丝束温度对1.33dtex×38mm缝纫型短纤维强、伸度的影响,结果证明:对成品纤维强度的影响依次为拉伸倍率、纺速、DF3出口温度;对断裂伸长率的影响依次为拉伸倍率、纺速、DF3出口温度。在实际生产中,选用纺速1300m/min、拉伸倍率3.7、DF3出口温度190℃左右的生产工艺,可生产出断裂强度为6.20cN/dtex、断裂伸长率为23%±4%的合格产品。 相似文献
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