纳米SiO_2对酚醛环氧树脂改性研究

以双酚A及甲醛为基本原料,加入纳米SiO2制备了纳米氧化硅改性酚醛树脂预聚体,其与环氧树脂继续共聚得到纳米氧化硅改性酚醛环氧树脂。通过红外光谱、粒径分布仪、X射线衍射、扫描电镜分析及涂膜性能测试对产物进行了研究和表征。结果表明,纳米氧化硅均匀分布在共聚物中,说明纳米氧化硅中的羟基参与了酚醛的共聚;纳米SiO2的加入对酚醛环氧树脂的结构无太大影响。与未改性醛醛环氧树脂比较,纳米SiO2的加入可有效提高涂层的耐水煮、黄变、硬度、吸水率及耐盐水腐蚀性。     

Addition‐cure phenolic resins based on propargyl ether functional novolacs: synthesis,curing and properties

Thermosetting phenolic resins, bearing varying extents of propargyl ether groups (PN resins), have been synthesized by the Williamson reaction of a novolac with propargyl bromide and the products characterized. The resin precursors were cured through Claisen rearrangement of the propargyl ether groups and thermal polymerization. The activation energy for thermal cure is substantially lower than that of model bispropargyl ether compounds but is quite independent of the degree of functionalization. The isothermal cure profile, extrapolated from non‐isothermal DSC kinetics studies is consistent with the results from DMA studies. The mechanical properties of glass composites of the resins, of varying propargyl contents, reveal good consolidation of the interphases, evident from the initial gain in both interlaminar shear strength (ILSS) and flexural strength. The benefits of better resin–reinforcement interactions are not retained on crosslinking the resin further, wherein the composite fails by a combination of fibre debonding and brittle fracture of the matrix. Although the resins show better thermal stability than cured resoles, a higher extent of propargylation is detrimental for the thermal stability. Resins with moderate propargylation show good mechanical and thermal properties. © 2001 Society of Chemical Industry     

纳米粒子改性酚醛树脂的研究进展

酚醛树脂是航空航天领域中一个重要的耐烧蚀材料。但是为了获得综合性能更优良的材料,需要对其进行改性。纳米粒子已成为增强增韧酚醛树脂的一种重要方法。本文重点介绍了纳米粒子增强增韧酚醛树脂的机理,同时对纳米碳材料(碳纳米管,石墨烯和炭黑),纳米SiO,纳米Al O,纳米TiO,纳米蒙脱2 2 3 2土对复合材料的性能的影响进行了阐述。并对纳米粒子改性酚醛树脂的发展趋势做了展望。     

碳纳米管改性酚醛树脂固化动力学研究

采用非等温示差法分析了碳纳米管改性酚醛固化反应过程,运用Kissinger和Ozawa法对其进行了动力学研究,得到了反应活化能。结果表明:碳纳米管改性PF树脂的固化反应为吸热反应;相应的峰始温度(Ti)为106.4℃,峰顶温度(Tp)为118.2℃,峰终温度(Tf)为157.6℃,固化体系的表观活化能Ea为111.094 kJ/mol,频率因子为9.56×10-5/s,反应级数为0.965,并得到了固化反应动力学方程。     

Correlation between retention and adsorption of phenolic compounds in nanofiltration membranes

Equilibrium adsorption experiments of phenol, 3-chlorophenol, 4-chlorophenol, and 3-nitrophenol aqueous solutions on NF90 membrane were conducted to obtain the corresponding adsorption isotherms at 25 ºC. Single-compound solutions with concentration ranging from 0.1 to 8 mmol L^− 1 were used. Freundlich and Langmuir models were compared to the experimental isotherms and their characteristic parameters were obtained from linear fits. In addition, the adsorptive behaviour of twelve aqueous phenolic compounds on the NF90 membrane was studied in order to investigate the relationship between adsorption and retention of selected solutes. An inverse correlation between the adsorbed amount, at the same equilibrium concentration (1 mmol L^− 1), and retention was found. The influence of the molecular hydrophobicity and dipole moment of phenolic compounds on membrane adsorption, solute retention and water flux decline was also investigated.     

酚醛树脂改性氨基模塑料

用酚醛树脂对氨基模塑料进行改性,使成型性得到改善,制品韧性增强。制备了酚醛树脂改性氨基模塑料,并讨论其加工成型特性和韧性的提高。     

催化臭氧化处理酚类化合物的研究进展与机理解析

催化臭氧化技术具有操作简单、氧化效率高、二次污染小等特点,在水中酚类化合物的去除方面具有较大的技术优势。本文以酚类化合物的催化臭氧化处理为切入点,介绍了均相催化臭氧化（二价铁离子）和非均相催化臭氧化（金属型、硅基负载型、碳基负载型、铝基负载型）处理不同浓度梯度酚类化合物的研究进展。然后,基于上述研究进展,根据污染物氧化过程的探针实验结果、催化剂表征特性和有机物转化规律,阐述了苯酚等酚类化合物的催化臭氧化机理。最后,从新型催化剂的再开发、酚类化合物的广谱催化和催化氧化机理的进一步探讨方面对催化臭氧化处理酚类化合物进行了展望。     

Analysis of phenolic compounds obtained from bamboo microwave liquefaction for fast-curing phenol-formaldehyde resin preparation

Three wastes originated from outer surface, shallow surface, and inner surface of bamboo during bamboo-mat preparation were liquefied using microwave energy in a binary solvent (glycerol/methanol). The properties (yield, molecular structure, and molecular weight distribution) of the lignin fractions in the obtained phenolic compounds were contrastively analyzed with proto-lignin in the materials. Results showed that >58% of the lignin in the bamboo cell walls could be degraded and moved to the phenolic compounds via the cleavage of β-O-4′ aryl ether bonds during the microwave liquefaction process. Some polysaccharides still connected with the lignin fraction in the phenolic compounds through covalent bonds. The phenolic compounds displayed well solubility in common organic solvents (ethanol/water cosolvent, acetone, tetrahydrofuran, 1,4-dioxane, and dimethyl sulfoxide). A fast-curing phenol-formaldehyde resin was successfully synthesized with the phenolic compounds under the presence of MgO, and a 23.23% curing time reduction was achieved. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46952.     

提高酚醛树脂耐热性的研究进展

全面介绍了耐火材料用酚醛树脂的改性方法,包括无机物改性、有机物改性等,着重介绍了最有前景的钼酸、硼酸改性方法和邻苯基苯酚改性方法,说明了其反应原理、改性合成工艺、主要影响因素。对其他几种改性工艺也作了简要说明,并对耐火材料用酚醛树脂改性方法的发展前景作出了分析。     

酚醛树脂的改性研究进展

综述了近3年采酚醛树脂耐热和增韧改性的研究进展简要介绍了各种方法的改性机理及研究现状最后对酚醛树脂改性方法的发展前景作出了展望.     

蒸馏妥尔油改性酚醛树脂的合成与应用

利用造纸厂纸浆废液中分离出的蒸馏妥尔油,合成了改性酚醛树脂,并对反应机理和树脂结构进行了分析。结果表明,当苯酚与甲醛的摩尔比控制为1∶0.6~0.9,蒸馏妥尔油加入量为苯酚的40%~60%时,改性的酚醛树脂性能最佳,与聚合物和溶剂的混溶性得到提高。     

有机硅改性酚醛环氧树脂耐高温胶粘剂的研制

采用甲基苯基硅树脂对酚醛环氧树脂进行改性,硼酚醛树脂与自制固化促进剂作为固化剂,辅以纳米蒙脱土、绢云母粉作为填料,制备出一种能在300℃条件下长期使用的耐高温胶粘剂。在不同的配方及固化工艺条件下測定了有机硅改性酚醛环氧树脂体系的剪切强度,分析了甲基苯基硅树脂／酚醛环氧树脂比例关系、硼酚醛树脂与自制固化促进剂比例关系、固化剂用量、固化工艺条件、纳米蒙脱土的加入量对体系的影响。     

Nanoclay and long-fiber-reinforced composites based on epoxy and phenolic resins

In this study, high-performance thermoset polymer composites are synthesized by using both long fibers and nanoclays. Epoxy and phenolic resins, the two most important thermoset polymers, are used as the polymer matrix. The hydrophobic epoxy resin is mixed with surface modified nanoclay, while the hydrophilic phenolic resin is mixed with unmodified raw nanoclay to form nanocomposites. Long carbon fibers are also added into the nanocomposites to produce hybrid composites. Mechanical and thermal properties of synthesized composites are compared with both long-fiber-reinforced composites and polymer- layered silicate composites. The optimal conditions of sample preparation and processing are also investigated to achieve the best properties of the hybrid composites. It is found that mechanical and thermal properties of epoxy and phenolic nanocomposites can be substantially improved. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

酚醛树脂的复合改性研究进展

综述了酚醛树脂增韧和耐热复合改性的研究进展,分析了各种方法的改性机理及研究现状。包括用橡胶、CNSL、桐油、新型固化剂改性酚醛树脂的韧性,用钼、硼、无机纳米材料、聚酸亚胺改性酚醛树脂的耐热性。并对酚醛树脂复合改性方法的发展前景作出了分析。     

有机硼改性酚醛树脂的合成

以硼酸,苯酚,甲醛为原料,碳酸钠作催化剂合成具有耐高温性能的硼酚醛树脂。通过IR,对这种热固性有机硼改性酚醛树脂的结构进行了表征。树脂的热失重分析结果表明此树脂耐热性优于普通酚醛树脂,所得产物在900℃残留物为76．38％。确定了最佳反应条件为:苯酚:甲醛:硼酸=1:2:0．3(摩尔比),缩合反应温度70-75℃,硼酯化反应温度100-104℃,在控制反血时间下脱水一次。     

硼酚醛树脂的制备和研究进展

由于在酚醛树脂(PF)的分子结构中引入了无机硼元素,故硼酚醛树脂(BPF)具有优异的抗氧化性、高温稳定性、力学性能和高残炭率等特点,并且在热解时不会释放出有毒气体,因而已成为目前最成功的PF改性品种之一,在汽车、军事装备和航空航天等领域中应用广泛。总结了国内外近年来有关制备BPF的各种方法,简要介绍了BPF的性能及应用研究,并对该领域的研究方向作了展望。     

Novel phosphorus‐containing dicyclopentadiene‐modified phenolic resins for flame‐retardancy applications

2‐[4‐(2‐hydroxyphenyl)tricyclo[5.2.1.0^2,6]dec‐8‐yl]phenol (HPTCDP) were prepared from dicyclopentadiene (DCPD) and phenol via Friedel‐Crafts alkylation. DCPD‐containing phenolic resin (DPR) was also synthesized by incorporating the DCPD‐containing monomer HPTCDP with formaldehyde. DPR was further modified by grafting the phosphate group. The phosphorylation was confirmed by a Fourier transform infrared, ³¹P‐NMR spectroscopy, and an element analysis. The phosphorus content in the DPR could be successfully tailored to give values of 3.46 to 7.79 wt % by varying the feeding ratios of the phosphorus group. The thermal stabilities of the phosphorus‐containing polymers were identified by differential scanning calorimeter and thermogravimetric analysis. The glass transition temperature values were decreased as the content of phosphorus increased. High char yield 39–47 wt % in thermogravimetric analysis evaluation and limiting oxygen index values of 27 to 34 were found for all the phosphorylated phenolic resins. Such properties make these polymers highly promising for flame‐retardant applications. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 342–349, 2001     

煤焦油改性酚醛树脂的合成研究

采用正交试验法,探讨了不同物质的量比、反应时间以及催化剂用量对酚醛树脂性能的影响,并借助红外光谱(FTIR)对生成产物的结构进行分析,热重分析法(TCA)对其热稳定性进行表征.通过对改性后树脂的固含量和残炭率的测定分析,得到了合成树脂的优化条件:n甲醛:n苯酚=1.3:1,反应时间100min,NaoH用量为苯酚质量的1.1%.以煤焦油为改性剂时其改性,并对其固舍量、残炭率、水分及游离酚进行测定,结果表明,加入煤焦油后树脂的品质得到了提高.     

Preparation of magnetic biochar derived from cyclosorus interruptus for the removal of phenolic compounds: Characterization and mechanism

A novel magnetic biochar was prepared via pyrolysis method and modification. The influence factors of contact time, initial concentration, temperature, and pH on the adsorption were investigated. The experimental results exhibited that the adsorption ability of methyl salicylate onto biochar was higher than that of phenol and para-chlorophenol under the same condition, which may be owing to the effect of hydrogen bonding, hydrophobicity, and π–π interaction. The maximum adsorption capacities of phenol, para-chlorophenol and methyl salicylate were 62.6, 131.6, and 169.7 mg/g at 298 K, respectively. This magnetic biochar exhibited high reusability (retained 82.1% after five cycles) and sharply magnetic performance (21.4emu/g).