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Rheological properties of self-adhesive phenolic resin and adhesion property of prepreg co-curing with Nomex honeycomb core

- , 2016, DOI: 10.13801/j.cnki.fhclxb.20150616.001
Abstract: 采用流变仪研究了固化反应温度、时间以及增韧剂和增稠剂加入量对酚醛树脂流变特性的影响,并测试了玻璃纤维增强酚醛预浸料与Nomex蜂窝芯共固化成型后玻璃纤维/酚醛-Nomex蜂窝夹层结构复合材料的板-芯黏接性能。结果表明:改性后酚醛树脂在高温时的黏度提高较多,流动性得到了有效改善,所得预浸料与Nomex蜂窝芯的界面黏接明显增强,并且当增韧剂和增稠剂的加入量与纯酚醛树脂的质量比分别为5%和3%时,所制备出的夹层板的滚筒剥离强度达到15 N·mm/mm以上,改性后酚醛树脂及其预浸料具有了一定程度的自黏附特性。此外,在共固化工艺中采用合适的升温制度,可以进一步提高玻璃纤维/酚醛-Nomex蜂窝夹层结构复合材料的板-芯黏接强度。 The influences of curing reaction temperature and time, toughening agent and thickening agent addition amounts on rheological properties of phenolic resin were investigated using rheometer. The glass fiber reinforced phenolic prepregs were also prepared to fabricate glass fiber/phenolic-Nomex honeycomb cored sandwich composites by co-curing technology with Nomex honeycomb core, and the adhesion properties of skin-core were measured. The results show that the viscosity of the modified phenolic resin at elevated temperature increases a lot and flow behavior is also well improved, the interfacial adhesion between the as-prepared prepreg and Nomex honeycomb core enhances obviously and the climb drum peel strength of the as-prepared sandwich panel can achieve to above 15 N·mm/mm when the mass ratios of toughening agent and thickening agent addition amounts are 5% and 3% to the pure phenolic resin, indicating the self-adhesive characteristics of the modified phenolic resin and its prepreg. Additionally, it can further increase the adhesion strength of skin-core for glass fiber/phenolic-Nomex honeycomb cored sandwich composite by applying a moderate heating profile in co-curing process.
Preparation of montmorillonite modified phenolic resin for shell process  [PDF]
Xiong Jianmin,Li Yuancai,Wang Wenqing
China Foundry , 2009,
Abstract: The development of montmorillonite modified phenolic resin under microwave irradiation heating was investigated. The effect of montmorillonite content and stirring time on the structure and morphology of synthetic resin was analyzed. The optimum processing procedure was found to be 45 min stirring time with 5.4% montmorillonite addition. Further, the platelet spacing increases with stirring time till montmorillonite exfoliated to nanoscales platelet. When montmorillonite is exfoliated, layered structure at nanoscale can be uniformly distributed in the resin. The overall performance of montmorillonite modifi ed phenolic resin is improved remarkably, such as fl ow ability, tensile strength and toughness property of resin coated sand. However, the gelation speed decreased slightly by adding montmorillonite.
Hydrogen Bonding-Mediated Microphase Separation during the Formation of Mesoporous Novolac-Type Phenolic Resin Templated by the Triblock Copolymer, PEO-b-PPO-b-PEO  [PDF]
Wei-Cheng Chu,Shih-Fan Chiang,Jheng-Guang Li,Shiao-Wei Kuo
Materials , 2013, DOI: 10.3390/ma6115077
Abstract: After blending the triblock copolymer, poly(ethylene oxide- b-propylene oxide- b-ethylene oxide) (PEO- b-PPO- b-PEO) with novolac-type phenolic resin, Fourier transform infrared spectroscopy revealed that the ether groups of the PEO block were stronger hydrogen bond acceptors for the OH groups of phenolic resin than were the ether groups of the PPO block. Thermal curing with hexamethylenetetramine as the curing agent resulted in the triblock copolymer being incorporated into the phenolic resin, forming a nanostructure through a mechanism involving reaction-induced microphase separation. Mild pyrolysis conditions led to the removal of the PEO- b-PPO- b-PEO triblock copolymer and formation of mesoporous phenolic resin. This approach provided a variety of composition-dependent nanostructures, including disordered wormlike, body-centered-cubic spherical and disorder micelles. The regular mesoporous novolac-type phenolic resin was formed only at a phenolic content of 40–60 wt %, the result of an intriguing balance of hydrogen bonding interactions among the phenolic resin and the PEO and PPO segments of the triblock copolymer.
Preparation of Silica Powder in Epoxy Resin Wear-Resistant Coating  [PDF]
Dongdong Zhang, Jihu Wang, Shaoguo Wen, Pengzhu Wang, Changle Yin, Zhongyan Du
Advances in Materials Physics and Chemistry (AMPC) , 2015, DOI: 10.4236/ampc.2015.52009
Abstract: Silicon powders possess good thermal stability and rub resistance and can be used as the filler of high temperature wear-resistant coating; it can possess good wettability and dispersibility in the organic polymer by surface modification of silane coupling agent. Organic silicon has good thermal stability, which can modify the frangibility and thermal stability of epoxy resin. A certain proportion of modified silica powder, curing agent and additives were dispersed to modified epoxy resin can compound wear-resistant coating. The results show that: the modification effect can be the best if the dosage of silane coupling agent is 1.5% of silicon powder. If the methyl triethoxy silane is 50 phr and modified silica powder is 200 phr, then various performances of coating tend to be the best.
Synthesis of a boron modified phenolic resin  [PDF]
Aparecida M. Kawamoto,Luiz Cláudio Pardini*,Milton Faria Diniz,Vera Lúcia Louren?o
Journal of Aerospace Technology and Management , 2010,
Abstract: Phenolic resin has long been used as matrix for composites mainly because of its flame retardant behavior and high char yield after pyrolysis, which results in a self supporting structure. The addition of ceramic powders, such as SiC and B4C, as fillers to the phenolic resin, results in better thermo-oxidative stability, but as drawbacks, it has poor homogeneity, adhesion and processing difficulties during molding of the composites. The addition of single elements, such as boron, silicon and phosphorus in the main backbone of the thermo-set resin is a new strategy to obtain special high performance resins, which results in higher mechanical properties, avoiding the drawbacks of simply adding fillers, which results in enhanced thermo-oxidative stability compared to conventional phenol-formaldehyde resins. Therefore, the product can have several applications, including the use as ablative thermal protection for thermo-structural composites. This work describes the preparation of a boron-modified phenolic resin (BPR) using salicyl alcohol and boric acid. The reaction was performed in refluxing toluene for a period of four hours, which produced a very high viscosity amber resin in 90% yield.The final structure of the compound, the boric acid double, substituted at the hydroxyl group of the aromatic ring, was determined with the help of the Infrared Spectroscopy, 1H-NMR, TGA-DSC and boron elemental analysis. The absorption band of the group B-O at 1349 cm ˉ1 can be visualized at the FT-IR spectrum. 1H-NMR spectra showed peaks at 4.97-5.04 ppm and 3.60-3.90 ppm assigned to belong to CH2OH groups from the alcohol. The elemental analysis was also performed for boron determination.The product has also been tested in carbon and silicon fibers composite for the use in thermal structure. The results of the tests showed composites with superior mechanical properties when compared with the conventional phenolic resin.
Study of Factors Affecting the Ablation Rate of Phenolic Resin/Fiber Glass
Nattawat Winya,Adulyasak Boonpan,Komson Prapunkarn
International Journal of Chemical Engineering and Applications , 2013, DOI: 10.7763/ijcea.2013.v4.302
Abstract: In this study, design experimental by two-level Factorial design to screen the factors to those factors that affect the ablation rate significantly. The following parameters were varied: amount of phenolic curing temperature and curing time. Factors that affect the ablation rate are as follows curing time, amount of phenolic resin, interaction between curing temperature and curing time, interaction between curing time and amount of phenolic resin, interaction between curing temperature and amount of phenolic resin and 3-way interaction of amount of phenolic resin, curing temperature and curing time. As the results of main effects analysis to determine 0.75 wt.% of phenolic resin, curing temperature 160 °C and curing time 35 min to give the ablation rate was 0.121 mm/s less than 0.14 mm/s according MIL-l-24768 standard.
Journal of Engineering Science and Technology , 2008,
Abstract: In this paper the effect of hardener on mechanical properties of carbon reinforced phenolic resin composites is investigated. Carbon fibre is one of the most useful reinforcement materials in composites, its major use being the manufacture of components in the aerospace, automotive, and leisure industries. In this study, carbon fibres are hot pressed with phenolic resin with various percentages of carbon fibre and hardener contents that range from 5-15%. Composites with 15% hardener content show an increase in flexural strength, tensile strength and hardness. The ultimate tensile strength (UTS), flexural strength and hardness for 15% hardener are 411.9 MPa, 51.7 MPa and 85.4 HRR respectively.

Yu Shang-ying,Shi Mei-yuan,Wu Yao-man,Huang Zhi-tang,

高分子学报 , 1980,
Abstract: A kind of thermosetting phenolic resin was prepared by the condensation of linear phenolic resin (Novolak) with formaldehyde. It exhibts higher carbon content lower modulus and similar thermal stability as compared with ordinary thermosetting phenolic resin, and can be used for preparation of composites.
Dispersing carbon nanotubes in phenolic resin using an aqueous solution
Botelho, Edson C.;Edwards, Elilton R.;Bittmann, Birgit;Burkhart, Thomas;
Journal of the Brazilian Chemical Society , 2011, DOI: 10.1590/S0103-50532011001100004
Abstract: the ability to control the carbon nanotube (cnt) dispersion in polymers is considered the key to most applications of nanotube/polymer composites. the carbon nanotube dispersion into water with different surfactants, as well as its incorporation into phenolic resins, was investigated. ultrasonication of liquid suspensions was used to prepare stable dispersions. in order to evaluate the best surfactant to be used, light scattering and uv-visible spectroscopy were employed. the structure of cnt reinforced of phenolic resin was analyzed in function of the concentration and type of surfactant, sonication power and time. it was also evaluated the influence in the dispersion by using the glass temperature transition properties being obtained by dynamic mechanical analyses and impact energy.
Characterisation of a phenolic resin and sugar cane pulp composite
Leite, J. L.;Pires, A. T. N.;Souza, S. M. A. G. Ulson de;Souza, A. A. Ulson de;
Brazilian Journal of Chemical Engineering , 2004, DOI: 10.1590/S0104-66322004000200015
Abstract: polymeric materials are increasingly replacing metallic materials as a result of their properties. in this work a composite of phenolic resin and sugar cane pulp was developed. the sugar cane pulp has been previously alkalinised, dried, and milled and the particles had been classified in a range of grain sizes. experimental assays were performed, varying the proportion of the resin and the reinforcement and the size of the cane pulp fibre, keeping the pressure and moulding temperature constant. these composites were characterised according to physical and chemical properties, through test bodies produced in moulds according to astm standards. the experiments performed showed that the use of sugar cane pulp as reinforcement in polymeric composites represents an option for reducing costs in industrial applications, thus suggesting a significant industrial applicability of the product.
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