固化和炭化条件对酚醛树脂基球形活性炭机械强度与吸附性能的影响

讨论了不同固化温度、固化时间以及炭化升温速率对酚醛树脂基球形活性炭机械强度与吸附性能的影响。结果表明,随着固化温度的升高,酚醛树脂基球形活性炭的机械强度先升后降,吸附能力先降后升。随着固化时间的延长,其机械强度增大,吸附能力下降。随着炭化升温速率的上升,机械强度下降,吸附能力增强     

固化和炭化条件对酚醛树脂基球形活性炭机械哟度与吸附性能的影响

讨论了在不同固化温度、固化时间以及炭化升温速率对酚醛树脂基球形活性机械强度与吸附性能的影响，结果表明：随着固化的同，酚醛树脂基球形活性炭的机械强度先升后降，吸附能力先降后升。随着固化时间的延长，其机械强度增大，吸附能力下降。随着炭化升温速度的上升，机械强度下降。吸附能力增强。     

孔结构对热解酚醛树脂制备碳纳米管的影响EI北大核心CSCD

以不同的酚醛树脂为原料经催化热解法制备碳纳米管时结果差异较大,为阐明存在的问题及原因,以酚醛树脂为碳源、硝酸铁为催化剂前驱体,通过催化酚醛树脂裂解的方法制备碳纳米管,研究了酚醛树脂中孔结构对合成碳纳米管的影响。采用X射线衍射、扫描电子显微镜和透射电子显微镜对酚醛树脂热解产物的物相组成及显微结构进行了分析。结果表明:1)碳纳米管仅生长在固化后酚醛树脂的大气孔(50~1 000μm)中,其直径约为40~100纳米,长度可达几百微米,其它位置基本无碳纳米管的生成;2)较大的气孔(50~1 000μm)可为碳纳米管的生长提供相对充足的碳源和生长空间,继而有利于碳纳米管的生成;3)较小的气孔(30μm以下)由于难以满足该条件而基本无碳纳米管的生成。碳纳米管的产率与酚醛树脂固化后形成气孔的大小有关,采用固化后能形成较大孔径的酚醛树脂为碳源可以提高碳纳米管的产率。     

孔结构对热解酚醛树脂制备碳纳米管的影响

以不同的酚醛树脂为原料经催化热解法制备碳纳米管时结果差异较大,为阐明存在的问题及原因,以酚醛树脂为碳源、硝酸铁为催化剂前驱体,通过催化酚醛树脂裂解的方法制备碳纳米管,研究了酚醛树脂中孔结构对合成碳纳米管的影响。采用X射线衍射、扫描电子显微镜和透射电子显微镜对酚醛树脂热解产物的物相组成及显微结构进行了分析。结果表明:1)碳纳米管仅生长在固化后酚醛树脂的大气孔(50~1 000μm)中,其直径约为40~100纳米,长度可达几百微米,其它位置基本无碳纳米管的生成;2)较大的气孔(50~1 000μm)可为碳纳米管的生长提供相对充足的碳源和生长空间,继而有利于碳纳米管的生成;3)较小的气孔(30μm以下)由于难以满足该条件而基本无碳纳米管的生成。碳纳米管的产率与酚醛树脂固化后形成气孔的大小有关,采用固化后能形成较大孔径的酚醛树脂为碳源可以提高碳纳米管的产率。     

高碳酚醛树脂及其复合材料的炭化性能演变

碳纤维增强酚醛树脂基复合材料是制备C/C复合材料的前驱体,但是目前所应用的酚醛树脂残炭率较低,浸渍炭化周期过长,工艺成本过高,限制了C/C复合材料在民用领域的大规模应用。因此,研究新型的高碳酚醛树脂及其作为基体的复合材料在炭化过程中的性能演变情况,可以有效促进酚醛树脂在C/C复合材料生产中的应用。本文探究了高碳酚醛树脂及其复合材料的炭化性能,研究了高碳酚醛树脂的结构、固化、耐热性,对高碳酚醛树脂及其碳纤维增强复合材料的炭化后性能进行了研究。研究结果表明:高碳酚醛树脂具有较普通酚醛树脂更高的残炭率;当炭化温度过高时,会出现无规则的非晶态的碳颗粒,影响材料的有序性、显气孔率等。在1000℃下炭化,会得到较为优异的孔隙率,利于后续制备工艺的进行。     

改性碳纳米管对三元乙丙橡胶导热性能和物理性能的影响

将未改性及酚醛树脂包覆改性碳纳米管填充到三元乙丙橡胶(EPDM)中,观察改性前后碳纳米管在橡胶基体中的分散情况,并研究碳纳米管/EPDM复合材料的热导率和物理性能。结果表明:经酚醛树脂包覆改性后,碳纳米管在橡胶基体中分散良好,复合材料的热导率和物理性能均有一定程度的提高;当碳纳米管与酚醛树脂用量比为1∶1时,改性碳纳米管/EPDM复合材料的热导率较高,物理性能较好。     

碳纳米管改性酚醛树脂的研究

研究了碳纳米管改性酚醛树脂的制备方法，以及碳纳米管预处理方法和碳纳米管用量对酚醛树脂性能的影响，并用透射电子显微镜（TEM）和热分析仪（TG）测得其微观结构和热性能。结果表明，碳纳米管能显著提高酚醛树脂耐热性。     

高能电子束辐射对硼酚醛树脂的影响

对硼酚醛树脂进行了高能电子束辐射,并进行了差热分析、热失重分析、残炭率和炭化后的粉末电阻率测试.结果表明硼酚醛树脂辐射前在100～200 ℃之间有一个明显的吸热反应峰,固化温度范围较大;而经过辐射后,100～300 ℃反应峰较少,硼酚醛树脂的固化温度范围明显减小,且固化温度降低.炭化后粉末电阻率由辐射前的3899.6 μΩ·m显著提高为辐射后的4951.6 μΩ·m;残炭率由60.6%降低为58.1%.     

使用碱式溴甲酚绿功能化多壁碳纳米管

使用碱式溴甲酚绿对多壁碳纳米管进行非共价键功能化处理,使其分散在水溶液中。染料分子的化学结构通过1H核磁共振谱,二维1H-1H相关谱以及质谱分析得以确定。原子力显微镜照片说明染料分子被吸附在碳纳米管上;拉曼光谱分析表明碳纳米管被分散在水溶液中。     

竹炭改性泡沫炭材料制备及铜离子吸附性能研究

以酚醛树脂为基体前躯体,竹炭为添加剂,通过发泡、固化及炭化工艺制备出竹炭改性酚醛树脂基泡沫炭材料,研究了其对Cu2+的吸附性能,探究了竹炭含量、吸附时间和溶液pH值对泡沫炭材料吸附Cu2+效果的影响。结果表明:在竹炭含量为7%~10%、吸附时间45 min、溶液pH值为9的条件下,Cu2+的吸附效果最好,并且从微观结构上解释了其对Cu2+吸附能力曲线的变化趋势,解决了泡沫炭因孔径大而难以吸附重金属离子的问题,降低了制备成本,扩大了泡沫炭材料的应用范围。     

锆改性酚醛树脂的合成与表征

以甲醛、苯酚、氧氯化锆为原料合成了高残碳锆酚醛树脂。研究了甲醛与苯酚物质的量比以及氧氯化锆的用量对树脂残碳率的影响,确定了合成工艺条件。用IR和TGA对产品的化学结构与热性能进行了分析,结果表明：锆元素以Zr-O-C键和Zr-O-Zr键的形式存在于锆酚醛树脂分子链中,与普通酚醛树脂相比锆酚醛树脂分子链中醚键含量降低、热稳定性提高,最大热分解温度和残碳率分别为560℃和62．5％,可作为优良耐高温和耐烧蚀的树脂基体材料.     

酚醛树脂热降解过程中的结构变化

采用综合热分析对比研究了自制酚醛树脂和商业酚醛树脂的热降解过程,利用固体核磁共振和红外光谱技术研究了热降解过程中树脂结构的变化规律以期指导成炭率高、热稳定性高的新型酚醛树脂的合成。结果表明:酚醛树脂的热降解过程可分为3个阶段:首先是醚键以及未反应的羟甲基等端基的热降解;其次是亚甲基热解断裂为甲基;然后是酚羟基发生脱水环化成炭。其中亚甲基的热解对酚醛树脂的热稳定性及高温下的成炭性能有着至关重要的作用。固体核磁共振比红外光谱更直接,更清晰地反应出酚醛树脂在热降解过程中的结构变化。     

Multi-walled carbon nanotubes (MWNTs) as an efficient catalyst for catalytic wet air oxidation of phenol

Multi-walled carbon nanotubes (MWNTs) were used as a catalyst for catalytic wet air oxidation (CWAO) of phenol in a batch reactor. SEM, TEM and FT-IR technique were applied to investigate the microstructure and the surface functional group of the MWNTs. When the carboxylic groups (–COOH) are grafted onto the surface of the MWNTs, the functionalized MWNTs exhibit a good catalytic activity in CWAO of phenol. At a reaction temperature of 160 °C, oxygen pressure of 2.0 MPa and a phenol concentration of 1000 mg/L, 100% phenol and 76% TOC are removed after 120 min reaction.     

Thermal degradation behavior of epoxy resin blended with propyl ester phosphazene

The study was focused on the thermal degradation behavior of epoxy resins (EP) blended with propyl ester phosphazene (FR). The analysis studied the evolved gas and the residual char yield using different techniques. The results showed that pure epoxy resin and their blends were all a one‐stage thermal degradation reaction. The major degradation temperature of blends was lower than the temperature of pure epoxy resin, but the residual char yield of epoxy blends at 550°C was higher than that of pure epoxy resin. FR could accelerate the production of small molecules such as acetone, phenol, and isopropyl phenol during thermal degradation process. Honeycomb structure compounds were also formed in the residual char of epoxy and its blends. Additionally, elemental analysis of the residual char yield showed that phosphorus was a residual element, and other elements mostly diffused to the evolved gas. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1161–1174, 2001     

高物质的量比低游离酚热塑性酚醛树脂的合成工艺

为降低耐火材料用酚醛树脂中游离酚的含量,选择苯酚与甲醛物质的量比1∶1.5,分步加入甲醛,醋酸锌为催化剂,添加质量分数2%,糠醇为溶剂,在60～85℃下制备了液态热塑性酚醛树脂,对产品的物化性能进行了测试并以红外光谱对其结构作了表征。结果表明,该工艺合成的酚醛树脂存在高邻位取代结构,残炭量达到45.66%,游离酚质量分数为1.87%。以原料中苯酚的量计算,产率可达到148.8%。     

Preparation and Properties of Nanocomposites Based on Hyperbranched Aliphatic Polyamide Functionalized Multiwalled Carbon Nanotubes and Bismaleimide Resin

Multiwalled carbon nanotubes (MWNTs) functionalized with hyperbranched aliphatic polyamide (HAP) were prepared by polycondensation using 3-(2-aminoethylamino)propanoic acid methyl ester as monomer. The effects of HAP functionalized MWNTs (MWNT-HAP) on the properties of bismaleimide (BMI) resin were investigated. Nanocomposites based on BMI resin and different content of MWNTs were prepared. The properties of nanocomposites were characterized by TGA, DMA, flexural and impact tests. Because of the magnification of functional groups and the higher interfacial interaction between MWNT-HAP and BMI resin, the improvement of the mechanical and thermal properties of MWNT-HAP/BMI nanocomposites was more remarkable than nanocomposites containing pristine MWNTs.     

High thermal conductive m‐xylylenediamine functionalized multiwall carbon nanotubes/epoxy resin composites

In this study, multiwall carbon nanotubes (MWNTs) functionalized by m‐xylylenediamine is used as thermal conductive fillers to improve their dispersibility in epoxy resin and the thermal conductivity of the MWNTs/bisphenol‐A glycidol ether epoxy resin composites. Functionalization with amine groups of MWNTs is achieved after such steps as carboxylation, acylation and amidation. The thermal conductivity, impact strength, flexural strength, and fracture surfaces of MWNTs/epoxy composites are investigated with different MWNTs. The results show that m‐xylylenediamine is successfully grafted onto the surface of the MWNTs and the mass fraction of the organic molecules grafted onto MWNTs is about 20 wt %. The thermal conductivity of MWNTs/epoxy composites is further enhanced to 1.236 W/mK with 2 wt % m‐MWNTs. When the content of m‐MWNTs is 1.5 wt %, the impact strength and flexural strength of the composites are 25.85 KJ/m², 128.1 MPa, respectively. Scanning electron microscope (SEM) results show that the fracture pattern of composites is changed from brittle fracture to ductile fracture. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41255.     

红外光谱法对苯基苯酚改性酚醛树脂的研究

本文利用红外光谱对苯基苯酚改性酚醛树脂进行了结构鉴定，并通过分析谱图中羟甲基、醚键含量的变化，研究了缩聚温度、聚合度对树脂结构的影响，结果表明苯基苯酚改性酚醛树脂从结构上就有利于获得较高的残碳率，而选择适当的反应条件可进一步提高树脂残碳率。     

Phenolic resins with phenyl maleimide functions: Thermal characteristics and laminate composite properties

Phenolic resins bearing varying concentrations of phenyl maleimide functions were synthesized by copolymerizing phenol with N‐(4‐hydroxyphenyl)maleimide (HPM) and formaldehyde in the presence of an acid catalyst. The resins underwent a two‐stage curing, through condensation of methylol groups and addition polymerization of maleimide groups. The cure characterization of the resin by dynamic mechanical analysis confirmed the two‐stage cure and the dominance of maleimide polymerization over methylol condensation in the network buildup process. The kinetics of both cure reactions, studied by the Rogers method, substantiated the earlier proposed cure mechanism for each stage. Although the initial decomposition temperature of the cured resin was not significantly improved, enhancing the crosslink density through HPM improved thermal stability of the material in a higher temperature regime. The anaerobic char yield also increased proportional to the maleimide content. Isothermal pyrolysis and analysis of the char confirmed that pyrolysis occurs by loss of hydrocarbon and nitrogenous products. The resins serve as effective matrices in silica‐ and glass fabric–reinforced composites whose mechanical properties are optimum for moderately crosslinked resins, in which failure occurs through a combination of fiber debonding and resin fracture. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1664–1674, 2001     

Thermal degradation of polymers. VIII. Ablation studies on a series of fiber-reinforced phenolic resin composites

The use of a laboratory ablation test rig for the assessment of tubular fiber-reinforced composites is described. Ablation resistance, char depth, smoke, and flash measurements have been made on a series of composites based on a standard phenol–formaldehyde resin incorporating various fibrous reinforcing agents. The results have been compared with those obtained from a standard asbestos-reinforced composite prepared from the same resin. Results are discussed in terms of the properties of the composite and of the fibrous reinforcing agent.