Synthesis and characterization of epoxy–silicone–polythiophene interpenetrating polymer network for corrosion protection of steel

Polymer alloys, particularly interpenetrating polymer networks (IPNs) exhibit excellent coating properties. Often combination of polymers result in IPNs with controlled morphologies and synergistic behavior. In this study, corrosion-resistant IPNs were prepared from immiscible resins (epoxy, silicone and thiophene) using a cross-linking agent and a catalyst. GPC, FTIR, NMR, TG, DTA and SEM studies used to fix the best performing IPN. Surface morphology studies using SEM confirm the incorporation of silicone and polythiophene in to the epoxy polymer to form homogeneously micro structured IPN. The heat-resistance of the IPN was determined as per ASTM 2485. The improved corrosion resistance of the IPN was evaluated by AC impedance measurements.     

热处理温度对ZrO2纤维复合ZrO2-C材料性能的影响

浸入式水口是钢铁连铸工序中关键的功能耐火材料,其中以渣线部位的工作环境最为恶劣。目前,最适合的渣线材料是ZrO₂-C材料。为了提高浸入式水口的性能,本文以氧化锆与鳞片石墨为主要原料,添加增强材料氧化锆纤维及金属硅粉等,以酚醛树脂为结合剂制备ZrO₂-C复合材料。比较了1 000 ℃、1 200 ℃和1 500 ℃三种热处理温度对ZrO₂-C材料的性能及显微结构的影响,结果表明,在热处理温度高于1 200 ℃时,ZrO₂-C材料中的硅粉与石墨发生反应生成碳化硅,大量晶须状碳化硅与ZrO₂纤维交错在一起形成网络结构,提高了材料的力学性能和抗热震性。     

添加剂对炭/石墨复合材料性能的影响

以酚醛树脂为黏结剂,石油焦、石墨为原料,分别添加磷酸氢二钠、硼酸、碳化硅,在1 100℃下热处理,制备出炭/石墨复合材料,并考察了其机械性能、微观结构和热性能。研究表明:经过焙烧后,炭/石墨复合材料中的添加剂起到增强颗粒间键合能力,提高炭/石墨复合材料机械强度的作用。同时,硼酸、碳化硅可以在炭/石墨复合材料表面形成抗氧化物质,使其具有更好的抗氧化能力,起始氧化温度提高180℃,终了氧化温度提高了200℃。     

碳化硅用量对轮胎胎面胶性能的影响

研究碳化硅部分替代补强炭黑在轮胎胎面胶中的应用.结果表明,轿车和载重轮胎胎面胶主要性能变化趋势一致,即随着碳化硅用量增大,胎面胶的物理性能有所降低,压缩疲劳温升和滚动阻力明显降低,抗湿滑性能提高,耐磨性能变差.碳化硅用量小于16份可以获得综合性能较好的胎面胶.     

Preparation and characterization of heat-resistant interpenetrating polymer network (IPN)

Interpenetrating polymer network (IPN) is a novel type of polymer hybrids, which possess physicochemical properties suitable for high performance coatings. Heat-resistant IPN have been prepared from immiscible resins, epoxy and silicones using a cross-linking agent and a catalyst. The products were analyzed by GPC, FT-IR, TG, DTA and SEM studies. The heat resistance property and corrosion behaviour of the IPNs were also determined. It was different from those of the individual resins. Silicone microdomains could be seen uniformly distributed in epoxy regions. Corrosion resistance property of the IPNs was evaluated by salt spray and impedance measurements. The IPNs withstood longer durations in the salt spray chamber.     

环氧树脂/碳化硅复合材料的热性能及韧性

采用碳化硅作为增强剂制备了环氧树脂/碳化硅复合材料,考察了复合材料的热学及力学性能。实验结果表明,碳化硅的添加使环氧树脂的玻璃化温度提高。当碳化硅添加质量分数为3%时,复合材料的韧性与纯环氧树脂相比提高了35%。     

环氧树脂耐热绝缘材料的研究

本文对用互穿网络方法制备环氧树脂绝缘材料进行了探讨，分别考察了环氧树脂、固化剂、添加剂及原料配比等对材料性能的影响。制备了具有较好工艺性、较高耐热性（F级）和机械性能的绝缘材料。     

Porous silicon carbide structures with anisotropic open porosity for high- temperature cycling applications

We have prepared porous silicon carbide by a novel two-step template method. Graphite/SiC composites of required size and shape are first fabricated by hot pressing at 2125 °C, followed by the removal of the graphite template by controlled heat treatment. The anisotropy in the composite structure is restored after the removal of the template and porous SiC with anisotropic properties is obtained. The composite can be easily machined by electrical discharge machining because of the presence of graphite, and porous SiC can be obtained by heat treatment, solving the inherent difficulty in the machining of SiC. The mechanical properties, thermal conductivity, and thermal shock resistance of porous SiC have been studied in both directions. The material shows good thermal shock resistance in the perpendicular to pressing direction even at 1400 °C. Hence porous SiC suitably machined preserving the proper direction can be a potential candidate for thermal cycling applications.     

Effect of Carbon Containing Materials on Pure Carbon Reaction-bonded SiC

Petroleum coke, graphite, gas carbon and lower sulfur carbon black were used to prepare reaction-bonded silicon carbide. The influences of different carbon containing materials on properties of carbonaceous precursors, sintering process, and microstructure of the prepared SiC were researched. The results show that ： （ 1 ） With the density of carbon containing materials increasing, the porosity of carbonaceous precursors decreases and the infiltrating process of liquid silicon is more difficult. （2） The reaction between carbon containing materials and liquid silicon, the volume effect is more obvious with the density of carbon containing materials increasing. （3） As the carbon containing materials density decreasing, residual carbon in reaction bonded SiC also decreases.     

Nanostructural Characterization of Silicon Oxycarbide Glasses and Glass-Ceramics

Silicon oxycarbide glasses were synthesized by the sol-gel process using precursors such as methyl-, propyl-, and phenyltrimethoxysilanes. The final products contained 14–38 wt% carbon. A TEM study on the nanometer scale revealed that all of the materials were amorphous and monophasic, and that it was not possible to detect any crystalline or otherwise distinct carbon phases. Hot-pressing the glasses led to the crystallization of graphite and silicon carbide within the amorphous matrix. X-ray and electron diffraction showed increasing crystallinity at the higher hot-pressing temperatures. Hot pressing at 1400°C resulted in the appearance of fine-grained silicon carbide, whereas at the highest temperature (1650°C), graphite and both hexagonal and cubic silicon carbide were produced. Subsequent heat treatment of the hot-pressed glasses under an argon atmosphere at 1400°C resulted in the formation of cristobalite. The glass-ceramics produced at the highest hot-pressing temperatures were more resistant to the crystallization of cristobalite during subsequent heat treatments.     

碳化硅/天然橡胶的制备与表征

为了提高橡胶的耐磨性,通过天然橡胶、SiC、炭黑的共混,在硫化时间一定的前提下,对其力学及磨耗性能测试。实验结果表明:混炼天然橡胶的拉伸性能随着碳化硅加入量的增加而提高,当碳化硅加入量达到12 g时(达到饱和)出现拉伸性能的最大值,之后虽碳化硅加入量的增加而下降。在相同条件下,不同加入量的磨耗比不同,与碳化硅在橡胶中的分布方式有极大影响。当碳化硅加入量在15 g时,其磨耗比达到最低值。热重分析数据结果表明:随碳化硅加入量的增加,橡胶的分解温度有所降低,但降低不是很明显,都是在350℃附近发生。碳化硅表面活化处理后再与天然橡胶共混,能够明显改善其力学性能及其它性能。     

Development of Low Density,Heat Resistant and Broadband Microwave Absorbing Materials (MAMs) for Stealth Applications

The development of low density and broadband microwave absorbers are the need of the hour to cater for the needs of all military platforms for stealth technology. The low density and broadband properties can be inculcated in microwave absorbers using dielectric lossy materials (e.g. carbon fibres, carbon nanotubes, carbon black, fullerene, graphite, graphene and silicon carbide fibre). Therefore, we designed low density and heat resistant microwave absorbing materials (MAMs) using a novel approach of ceramic fibre board manufacturing technology. The microwave absorbing composites were prepared with varying percentage of milled carbon fibres, discontinuous aluminosilicate fibres and silicone resin as the matrix. The physico-mechanical properties of microwave absorbing composites were determined. Reflection loss of microwave absorbing composites was measured in the frequency range 2–18 GHz by unique single horn interferometry technique. The electromagnetic properties were measured in X-band using free space measurement system. Based on these properties the effect of thickness on the microwave absorbing properties in X-band was simulated The effect of weight % variation of milled carbon fibres on the microwave absorbing properties of composites have been studied in the frequency range 2–18 GHz.     

熔融渗硅对石墨材料微观结构及性能的影响

选用四种不同孔隙结构的石墨进行熔融渗硅(简称熔渗)反应,采用扫描电镜、X-射线衍射、压汞、CT等方法表征了熔渗前后材料的微观形貌、物相及孔隙结构。结果表明,熔渗后的材料由石墨、硅及碳化硅三种物相组成,且硅及碳化硅的分布与石墨孔隙结构相关。熔渗后样品孔隙率均<1%,体积密度提高21.08%~35.94%。熔渗后材料强度及模量均有明显提高,强度是原石墨样品的1.7~6.2倍,模量是原石墨样品的2.4~7倍,提高幅度与石墨孔隙结构及晶粒尺寸相关。理论计算结果表明,石墨样品熔渗过程主要受扩散-反应控制。     

提高氮化硅结合碳化硅窑具使用性能的研究

氮化硅结合碳化硅窑具的抗热震性能被破坏、不合理的支撑方式、承重变形因素导致其使用性能降低,影响了氮化硅结合碳化硅窑具的使用寿命。本研究制备了氮化硅结合碳化硅窑具,并结合生产实际主要研究了如何提高材料的抗氧化性、抗热震性以及其他高温理化性能,使氮化硅结合碳化硅窑具使用寿命延长。     

Oxidation resistance before and after heat treatment for compacted Al<Subscript>2</Subscript>O<Subscript>3</Subscript>–SiC–C mixtures with aluminum-chromium-phosphate binder

Oxidation resistance has been examined for compacted Al₂O₃–SiC–C mixtures, which contain an aluminum-chromium-phosphate binder without firing (DTA method) and ones that have been previously fired and given isothermal heat treatment at 800°C (as indicated by the mass loss). To obtain oxidation-resistant materials, the content of silicon carbide should not exceed 10 wt.% and the recommended graphite content is not more than 20 wt.%. Translated from Novye Ogneupory, No. 2, pp. 38 – 43, February, 2009.     

Synergistic effects of carbon fillers on tensile and flexural properties in liquid‐crystal polymer based resins

One emerging market for thermally and electrically conductive resins is bipolar plates for use in fuel cells. Adding carbon fillers to thermoplastic resins increases the composite thermal and electrical conductivity. These fillers have an effect on the composite tensile and flexural properties, which are also important for bipolar plates. In this study, various amounts of three different types of carbon (carbon black, synthetic graphite particles, and carbon fibers) were added to Vectra A950RX liquid‐crystal polymer. In addition, composites containing combinations of fillers were also investigated via a factorial design. The tensile and flexural properties of the resulting composites were then measured. The objective of this study was to determine the effects and interactions of each filler with respect to the tensile and flexural properties. The addition of carbon black caused the tensile and flexural properties to decrease. Adding synthetic graphite particles caused the tensile and flexural modulus to increase. The addition of carbon fiber caused the tensile and flexural modulus and ultimate flexural strength to increase. In many cases, combining two different fillers caused a statistically significant effect on composite tensile and flexural properties at the 95% confidence level. For example, when 40 wt % synthetic graphite particles and 4 wt % carbon black were combined, the composite ultimate tensile and flexural strength increased more than what would be expected from the individual additive effect of each single filler. It is possible that linkages were formed between the carbon black and synthetic graphite particles that resulted in improved ultimate tensile and flexural strength. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of high temperature resistance interpenetrating polymer network

Interpenetrating polymer network (IPN) polymer has been prepared by blending silicone resin polymer with the organic polymers such as polypyrrole [PPy] and polythiophene [PTh]. The IPNs were characterized by FTIR, NMR, and TGA/DSC analysis. The heat resistance performance of these IPNs were evaluated as per ASTM D2485. The result indicates that the IPN based on silicone‐PTh has got superior heat resistant property than silicone‐PPy. The electrochemical impedance measurements showed that the corrosion resistances of both the IPNs was similar. AFM morphological study confirms the influence of PPy/PTh on silicone polymer in forming smooth heterogeneous micro‐structured IPNs. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

黑色耐磨防腐导电涂料的研制

利用有机硅树脂对环氧树脂进行改性,添加了一定量的纳米二硫化钼、纳米铝粉、导电碳黑和石墨,制作了一种黑色耐磨防腐导电涂料。实验表明,当有机硅树脂用量为12%,填料为8%,混合溶剂组成为m(丙酮):m(醋酸乙酯):m(醋酸丁酯):m(二甲苯)=2:1:1:1、用量为48%时,所得涂料耐磨性和防腐性能良好,涂层表面电阻达到了2.2×104?/cm2,具有较好的导电和防电磁性能。该涂料可以应用于陆军武器装备表面的电磁防护。     

Properties and behavior of CTBN‐modified epoxy with IPN structure

CTBN‐modified epoxy resins (CMEs) with an interpenetrating‐network (IPN) structure and a nanometer‐sized morphology were prepared. Two systems of CMEs, called CNE/DDS/I‐CTBN‐B and CNE/DDS/I‐CTBN‐D, with IPN structures, were synthesized by heat‐curing a homogeneous resin, CNE/DDS/CTBN/2‐MI, obtained by mixing a carboxyl‐terminated butadiene–acrylonitrile liquid rubber (CTBN) with a solution of polyglycidyl ether of o‐cresol‐formaldehyde novolac (CNE), 4,4′‐diamino diphenyl sulfone (DDS), and 2‐methyl imidazole (2‐MI), in the presence of benzoyl peroxide and dicumyl peroxide, respectively. The IPN morphologies of the two systems of CMEs were identified by small‐angle X‐ray scattering by measuring the value of the specific interfacial surface area S_sp between the cured CNE/DDS matrix and the vulcanized CTBN. Properties such as fracture toughness, internal stress, and thermal and dynamic mechanical properties of these IPN‐structured CMEs were studied in detail, and were compared with those of a conventional CME, CNE/DDS/CTBN, obtained by dispersing CTBN particles in a crosslinked CNE/DDS matrix. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Zn2+掺加的包覆型Fe2O3/SiO2颜料的制备及其呈色性能

包覆型Fe2 O3/SiO2颜料由于包覆完整性并不理想,该颜料高于800℃时呈色会产生变黑、变暗的问题.采用溶胶-凝胶法制备包覆型Fe2 O3/SiO2颜料,研究催化剂浓度、反应温度、硅/铁质量比等因素对包覆型Fe2 O3/SiO2颜料呈色性能的影响.在此基础上,通过掺加Zn2+,进行了Zn2+掺加的包覆型Fe2 O3...