陶瓷前驱体聚硅氮烷的制备研究进展

综述了合成Si-C-N陶瓷前体聚硅氮烷的一些方法,着重介绍了含金属聚硅氮烷的制备方法,如:含钛聚硅氮烷、铝基聚硅氮烷、铁基聚硅氮烷、锆基聚硅氮烷、硼基聚硅氮烷、钇基聚硅氮烷、铜基聚硅氮烷的制备方法;其次介绍了使用共聚法、超支化法、倍半硅氮烷水解法制备聚硅氮烷的方法。     

Si-C-N陶瓷前驱体聚硅氮烷合成的研究进展

综述了合成Si—C—N陶瓷前驱体聚硅氮烷的主要方法，即氨／Q解氯硅烷法、硅氮烷低聚物交联法、硅氮烷低聚物与氯硅烷反应法及氯硅氯烷和氯硅烷脱氯编聚法，并介绍了用铝、硼、钛、钇等元素对聚硅氮烷进行改性，以提高Si—C—N陶瓷性能的方法。     

含锆、硅有机陶瓷前驱体的制备及其陶瓷化研究

以正丙醇锆、乙酰丙酮,1,2-丙二醇为原料,制备主链为-Zr-O-CH2-CH-,侧链含有不饱和基团的含锆聚合物(ZMP)并作为锆源。将主链为-Si H、-C≡C-的硅炔树脂(PTSA)作为硅源。将二者以质量比2∶5进行复配,制得陶瓷前驱体(PMS)。采用FT-IR和NMR对ZMP结构进行表征,EDS分析了ZMP的元素组成;利用原位红外分别探讨了PMS的固化行为,运用TGA研究了PMS的耐热性能; TGA测试表明,陶瓷前驱体具有良好的耐热及热稳定性能,在氮气和空气气氛下1000℃时的质量保留率分别为90. 24%和88. 53%。通过XRD、SEM、TEM和Raman研究了PMS的陶瓷化演变。陶瓷化演变结果表明,PMS在1600℃下的陶瓷转化率高达57. 4%,且陶瓷产物中含高结晶度的Zr C、Si C晶体。     

陶瓷前驱体聚硅氮烷的应用研究进展(一)

综述了陶瓷前驱体聚硅氮烷在制备陶瓷涂层、陶瓷纤维、纳米材料、磁性陶瓷上的应用研究进展,指出了应用研究前景。     

陶瓷前驱体聚硅氮烷的应用研究进展（二）

综述了陶瓷前驱体聚硅氮烷在制备陶瓷基复合材料、超高温材料、催化剂、多孔材料、粘接陶瓷、3D打印材料、三维陶瓷微结构材料,电脑芯片的多层连接技术、锂电池阳极上的应用研究进展。     

液态聚硼硅氮烷的陶瓷化过程

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。     

SiBNC陶瓷纤维前驱体-聚硅硼氮烷的合成与表征

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%。     

聚硼硅氮烷固化氰酸酯基耐高温胶粘剂的制备与性能研究

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T_5%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。     

巯基/乙烯基硅氮烷紫外光固化的研究

利用原位红外跟踪技术和光-示差扫描量热技术研究了不同类型多官能巯基化合物与乙烯基硅氮烷的紫外光聚合动力学过程.结果表明,巯基化合物官能度越高,聚合反应速率越高,但最终转化率越低.巯基丙酸酯类化合物比烷基硫醇类化合物更易与乙烯基硅氮烷反应.在较低温度下,反应温度对聚合反应的影响较弱,反应活化能约为2.3kJ/mol,而较高反应温度下反应速率偏离Arrhenius方程.     

聚硅氮烷/环氧树脂固化体系的研究

研究了聚硅氮烷(PSN-1)/双酚A型环氧树脂固化体系的固化温度、PSN-1用量对固化速度的影响;并利用热重分析(TGA)研究了PSN-1用量对固化树脂高温残余质量分数的影响,对固化机理进行了初步探讨.结果表明,PSN-1可作为双酚A型环氧树脂的高温固化剂,在170～180℃范围内、PSN-1用量为20～50份时,均可有效固化双酚A型环氧树脂;采用PSN-1固化的环氧树脂的初始失重温度略低于采用三乙烯四胺(TETA)固化的环氧树脂,但在800℃时的残余质量分数均远远高于采用TETA固化的环氧树脂;且随着PSN-1用量的增加,环氧树脂的高温残余质量分数也增加.     

超支化聚酯改性酚醛树脂的制备与固化性能研究

以三羟基丙烷和二羟甲基丙酸为原料,缩聚反应制备了超支化聚酯（HBPE）,并制备了酚醛树脂/HBPE（PF/HBPE）共混体系。采用红外光谱、差示扫描量热分析等方法表征了HBPE的分子结构和PF/HBPE共混体系的性能,并用非模型等转化率法Flynn Wall Ozawa (FWO)描述了PF/HBPE共混体系的活化能与转化率之间的关系。结果表明,由于PF的酚羟基和HBPE的羟基产生了氢键作用,PF/HBPE共混体系显示出单一的玻璃化转变温度,HBPE的加入,提高了PF固化物的冲击强度和弯曲强度,当HBPE的含量为15 %时,冲击强度和弯曲强度分别为4.5 kJ/m2 和77.84 MPa。     

Preparation,Acid Curing,and Thermal Stability of Various Formulated Phenolic Resole Resins: Unfilled and Nanocomposites

Several phenol-formaldehyde resole resins were prepared with variety in monomers ratio, catalyst type, and content, having different nanoclay levels; then they were cured using various acids in the wide range of concentration. The acid-curing process was studied, considering gel time (t_G) and cure time (t_C). In addition, the thermal stability was investigated before and after cure for all samples. With increasing F/P ratio, t_G, t_C and t_G-t_C decreased and also C_C (critical concentration). By using more catalyst in the synthesizing step, the curing was done more rapidly in the order of NaOH, Ba(OH)₂ and NH₃. Stronger acids having smaller pK_a made a more realizable cure. However, the weak boric acid had no curing effect. Nanocomposites had shorter t_G and t_C, mainly at lower acid concentration. The structure peak of nanoclay shifted to the lower angles in nanocomposites, especially in the cured state. Crosslinked samples had higher degradation temperature (T_D) and lower weight decrease (Δ_w) related to the primary resoles. For uncured resins, thermal stability increased with decreasing of F/P ratio, and the inverse effect was found for the cured resins. Resins cured with HCL had higher T_D and lower Δ_w. However, at 30% concentration the sample cured by H₂SO₄ was more stable. With increasing catalyst amount and reactivity, T_D increased and Δ_w decreased. In all acid concentrations, at the presence of nanoclay the better thermal resistance was observed. T_D increased and Δ_w decreased as the nanoclay level increased.     

液压系统的泄漏与防治

本文主要讨论了液压系统的泄漏与防治方法,希望大家在设计及使用液压装置时不要忽视这个问题。     

低聚物型溴／氮阻燃剂在环氧树脂中的应用

以α，α’，2，3，5，6-六溴对二甲苯与乙二胺的线形低聚物（BNFR）为阻燃剂，采用热分析、红外光谱、有限氧指数和UL94V燃烧实验分析了BNFR对环氧树脂热性能和阻燃性能的影响。结果表明：BNFR能够参与树脂的固化反应，通过化学键成为树脂立体固化网络的组成部分。加入BNFR后，体系热降解5％和10％时的热降解温度均升高了15℃。在常规环氧树脂中添加6％BNFR（间苯二胺为固化剂）或者11％BNFR（邻苯二甲酸酐或JAq改性胺为固化剂）即能赋予基材UL94V-0的阻燃级别，有限氧指数大于26。使阻燃体系交联密度增加的固化剂及固化条件能进一步提升该体系的阻燃性能和热性能。阻燃体系中，n（Br）：n（Sb）最佳配比为3：1。     

The Preparation and Cure Kinetics Researches of Thermal Conductivity Epoxy/AlN Composites

The aluminum nitride (AlN) was employed to prepare epoxy/AlN composites by blending-casting moulding method, two different coupling agents were used to functionalize the surface of AlN. The thermal conductivity and mechanical properties of the composites were investigated. And the cure kinetics of the EP/AlN composites was studied by means of isothermal DSC. Results revealed that the thermal conductivity of EP improved remarkably with the addition of AlN, a higher thermal conductivity of 1.05 W/mK can be achieved with 42 vol% AlN, about 5 times higher than that of native epoxy resin. And the flexural and impact strength of the EP/AlN composites were optimal with 3.3 vol% AlN. The curing process of the EP/AlN composites contained autocatalytic mechanism, the whole process was according with the Kamal model. The presence of AlN did not change the cure reaction mechanism, and had little effecting on the activation energy, but decreased the rate constants k_l and k₂.     

UV-Curable Coating of Unsaturated Polyester/Epoxy Resins Containing Polyhedral Oligomeric Silsesquioxanes

UV-curable coating of unsaturated polyester/epoxy resin (UP-ER) modified with methylacryloylpropyl polyhedral oligomeric silsesquioxanes (MAP-POSS) was prepared. The UV-cured process, kinetics, and some properties of coating were investigated. The results show that this coating has a better UV-curing property. The curing reaction can be described by a two-parameter autocatalytic ?esták-Berggren (S-B) model. The mechanical loss peak temperature T _p of curing coating nanocomposites increased with increasing MAP-POSS content and has a highest value when MAP-POSS content is 12%, which is 121.8°C, and higher, about 18.3°C, than a pure UP-ER system. The coating film has lower volume shrinkage than pure UP-ER.     

ACS树脂的结构与热性能

通过相差显微图片和红外光谱分析ACS树脂[丙烯腈(AH)-氯化聚乙烯(CPE)-苯乙烯(S_t)]的结构,利用差热分析(DTA)和热失重(TG)曲线剖析ACS树脂的热性能。结果表明,ACS树脂系CPE、CPE-g-AS和AS以分散的橡胶相(CPE相)与连续的塑料相(AS相)共存的多相抗冲体系。CPE和ACS的热解聚机理均为脱氯化氢,氧化降解。ACS热稳定性明显优于CPE。     

笼型倍半硅氧烷基聚合物的制备和结构性能以及应用

笼型倍半硅氧烷基聚合物是一种典型的多面体有机／无机分子复合物材料,因其具有优异的光、电、热、磁、声、力学和化学相容性等性能,所以近年来被引入较为尖端的技术领域进行研究和应用。本文归纳总结了笼型倍半硅氧烷基聚合物的现行制备方法,讨论了笼型倍半硅氧烷结构对材料性能的影响。最后,对笼型倍半硅氧烷基聚合物材料的应用领域和发展趋势进行了说明。     

On the Cure Acceleration of Oil-Phenol-Formaldehyde Resins with Different Catalysts

Oil-phenol-formaldehyde (Oil-PF) resins containing 50 wt% replacement of petroleum phenol with bio-oil were prepared and different catalysts [sodium carbonate (Na₂CO₃), urea, and magnesium oxide (MgO)] were added in the synthesis process of resins to accelerate the cure. The cure-acceleration effects of catalysts on cure characteristics of oil-PF resins were investigated by using differential scanning calorimetry (DSC), gel time, and a plywood panels test. The results indicated that catalysts presented different accelerating effects on the cure of the oil-PF resin. Both Na₂CO₃ and MgO can accelerate the oil-PF resin cure at a low temperature; however, urea seemed to have no significant effect on the cure of the resin. The application of Na₂CO₃- and MgO-accelerated oil-PF resins reduced hot pressing time for the manufacture of three-layer plywood panels. Compared with MgO, Na₂CO₃ had more significant accelerating effect on the cure of the oil-PF resin.