腰果壳油改性摩擦材料用酚醛树脂的研究进展

腰果壳油是天然有机酚化合物,利用其改性摩擦材料用酚醛树脂具有改善材料力学性能和降低成本等优点,本文介绍了腰果壳油的组成及特性,简述了腰果壳油酚醛树脂的制备方法、改性途径及改性树脂用于摩擦材料方面的研究进展,进而展望了该树脂研究的前景。     

腰果树脂漆的制备

采用工业腰果壳液(CNSL)和甲醛缩聚反应合成具有良好性价比的腰果酚甲醛树脂，并以此配制了腰果树脂漆。着重讨论CNSL和甲醛的摩尔比及反应保温时间对树脂性能的影响，同时提供了各种腰果漆的配方及其性能指标。     

Hybrid Polymer Networks of Epoxy Resin and Substituted Phenolic Novolacs

Hybrid polymer networks of diglycidyl ether of bisphenol (DGEBA) resin and phenolic novolac resins were prepared and tested for mechanical properties, hardness, and water absorption. The novolacs employed were based on each of phenol and substituted phenols such as p-cresol, t-butyl phenol, and cardanol. Cardanol is the main constituent of cashew nut shell liquid (CNSL), a renewable resource. Blends containing 10–15 wt% of novolac resin show substantial improvement in properties. These properties show a declining trend with higher novolac loading. The stoichiometric ratio between phenol and formaldehyde in the novolacs was optimized (1:0.8) for maximum property enhancement. The property profiles of the epoxy/novolac networks show that novolacs are effective modifiers for commercial epoxy resin. Incorporation of novolacs of substituted phenols results in relatively greater improvement in energy absorption during failure.     

Jute felt composite from lignin modified phenolic resin

Raw and dewaxed jute felt composites were prepared with resol and lignin modified phenol formaldehyde resin. Four different types of lignin modified resins were used by replacing phenol with lignin. The lignin modified resins were prepared from purified lignin obtained from paper industry waste black liquor. To investigate bonding between jute and resin, IR spectroscopy of jute felts and composites was carried out. The thermal stability of the composites was assessed by DSC and TGA. It was found that the lignin resin jute composite is thermally more stable than resol composite. XRD of jute felt and composite shows that the crystallinity of the jute fiber increases after composite preparation. The lignin resin composites were tested for water absorption and thickness swelling, and it was found that the results are comparable with those of resol jute composite. Composites prepared from lignin phenol formaldehyde resin with 50% phenol replacement has shown 75% tensile strength retention to that of pure resol jute composite.     

Coconut-fiber-reinforced thermosetting plastics

Thermosetting plastic composites have been prepared with phenol–formaldehyde resins as well as unsaturated polyesters as binders and coconut hair as fibrous reinforcement. Using resole-type phenol–formaldehyde resins, the effect of coconut fiber pretreatment by NaOH, the precondensation time of the impregnated fibrous press material, the resin–fiber ratio, and pressing parameters have been studied. Especially advantageous press-material has been obtained using 60–65 wt % linear novolac type phenol-formaldehyde resin as binder and 35–40 wt % of coconut hair. Applying unsaturated polyester (UP) as binder, BMC (bulk molding compound)-type press material can be prepared using coconut fiber reinforcement instead of glass fibers. To achieve better coupling between coconut fiber and UP matrix, coconut fiber was pretreated by NaOH and/or gamma-preirradiation. It has been found that in glass-fiber-reinforced UP press materials a significant part of glass fiber could be changed for short-cut coconut fiber.     

Characterization of substituted phenol–formaldehyde resins using solid-state carbon-13 NMR

Crosslinked substituted phenol–formaldehyde resins were synthesized from cashew nut shell liquid, 3-n-pentadecylphenol and phenol with formaldehyde. The resulting resins were crosslinked and investigated using carbon-13 NMR in the solid state using cross-polarization, magic angle spinning, and dipolar decoupling. Comparisons were made between the spectra of pure phenol–formaldehyde resins and it was shown possible to distinguish between the resins. It was also shown that the proton-dephased spectrum gave better spectral resolution for the substituted compounds. In addition, the solids carbon-13 technique verified that the degradation of the substituted phenolic resins occurs first with the degradation of the side chain in agreement with suggestions from earlier work.     

Cardanol biocomposites reinforced with jute fiber: Microstructure,biodegradability, and mechanical properties

This work aims at studying the preparation and characterization of composites of phenolic resin (matrix) based on cashew nut shell liquid, reinforced by natural jute fibers. The fibers were chemically modified using alkaline treatment with solutions of NaOH (5 and 10%) and bleached with sodium hypochlorite NaClO/H₂0 (1:1) at 60–75°C. The microstructure was investigated by Scanning Electron Microscopy to observe the fiber surface after the treatment. As a result, there was an improvement in the thermal stability of the fiber, which was verified by Thermogravimetric Analysis. The jute fiber composites showed an improvement in their mechanical properties due to chemical treatment with 5% NaOH. Their biodegradability level depended on the employed alkali solution concentration. This study is important to evaluate the application of the fibers as renewable materials. POLYM. COMPOS., 31:1928–1937, 2010. © 2010 Society of Plastics Engineers.     

Jute fabric reinforced engineering thermoplastic sandwich composites. I. The effect of molding time

Jute fabric‐reinforced sandwich composites were fabricated using engineering thermoplastics. The jute fabrics were precoated with thermosetting resin to improve their thermal resistance before molding of the composites. Thermal gravimetric analysis (TGA) studies revealed that the resin coated fabrics decomposed at higher temperature than the uncoated jute. The onset of degradation of the coated fibers also falls between that of jute fibers and the thermoset resins. This indicates the presence of good interfacial bonding between jute fibers and both resins. Isothermal TGA studies revealed that jute could withstand brief exposure to higher temperature at 270 and 290°C. The sandwich composites were fabricated at 270°C by compression molding for 1.5 and 3 min in each case, and then characterized by flexural, tensile and morphological studies, i.e., SEM and optical microscopy. The uncoated jute fabric yielded composites of superior mechanical properties even with 3 mins molding at 270°C which is close to the degradation temperature of uncoated jute fibers. This is an indication that it is feasible to prepare jute fiber filled engineering polymer composites provided the exposure time at high temperature during processing does not exceed 3 mins as determined by TGA isothermal studies. SEM studies revealed strong fiber/matrix interfacial bonding between jute and the thermoset resins while the inferior mechanical properties of the resin coated sandwich composites could be attributed to the poor interfacial bonding between the already cured thermoset coating and the matrix based on optical microscopy of the polished cross‐sections. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Studies on Metal-to-Metal Adhesives Based on CNSL Resins

In this study the adhesive properties of a blend of polychloroprene rubber and a resin derived from cashew nut shell liquid (CNSL) are investigated. The resin is a copolymer obtained by condensing a mixture of CNSL and phenol with hexamethylene tetramine. The effects of varying the stochiometric ratios between total phenol and formaldehyde, CNSL and phenol, resin content, choice and extent of fillers, and adhesion promoters in the adhesive formulation were studied. The results show that CNSL-based resin is an effective ingredient in adhesives for bonding aluminium to aluminium. This is significant from the viewpoint of conservation because CNSL is a renewable resource and a cheap agricultural by-product.     

不同种类酚醛树脂黏结剂对摩擦材料性能的影响

分别以未改性通用酚醛树脂、特殊改性刹车片专用酚醛树脂、腰果壳油改性酚醛树脂、丁腈橡胶改性酚醛树脂为黏结剂,玄武岩纤维、钢纤维为增强纤维制备四种酚醛树脂基摩擦材料.对试样进行物理性能、机械性能和摩擦磨损性能测试.结果 表明,四种摩擦材料的密度相差不大,未改性通用酚醛树脂基摩擦材料的硬度符合刹车片使用要求,腰果壳油改性酚醛...     

腰果壳油改性酚醛树脂在轿车子午线轮胎高硬度三角胶中的应用

对比研究4种不同牌号酚醛补强树脂的理化性能及其对轿车子午线轮胎高硬度三角胶性能的影响。结果表明:国外A与国内2201牌号腰果壳油改性酚醛树脂的相对分子质量和软化点相近,使用这两种树脂的胶料性能相当;国外B与国内2201H牌号腰果壳油改性酚醛树脂的相对分子质量和软化点较高且相近,酚醛树脂2201H胶料的加工安全性更好,其他性能与酚醛树脂B胶料相当。     

木质素改性高耐磨酚醛树脂的制备及性能研究

利用酶解木质素(EHL)和腰果壳油(CNSL)改性热塑性酚醛树脂,讨论了不同酚醛摩尔比、CNSL用量和1,4-丁二醇对改性树脂性能的影响。研究表明,木质素及腰果壳油双改性的酚醛树脂耐热性能优于腰果壳油改性的酚醛树脂。改性后酚醛树脂基摩擦材料具有良好的摩擦磨损性能,更适合作为摩擦材料的树脂基体。     

Synthesis,Characterization, and Composite Properties of Casein Incorporated p-Aminophenol-Urea-Formaldehyde Copolymers

ABSTRACT

Modified Urea-formaldehyde (UF) thermosetting resin, containing casein and p-amino phenol has been synthesized by polycondensation of urea, casein, and formaldehyde in the presence of varying proportion of p-aminophenol under alkaline condition. All the prepared resins were characterized by free-formaldehyde content, free-phenol content, viscosity measurements, and infrared spectroscopy (IR). Their curing kinetics were studied isothermally and also by Differential Scanning Calorimetry (DSC) on dynamic run. The resin samples were cured isothermally at 120°C using two different curing agents, that is p-toluene sulphonic acid (PTS) and hexamine, to understand the curing behavior of novel resin samples. The cured resins were characterized by IR and thermogravimetric analysis (TGA). The resin samples were employed for the fabrication of glass fiber and jute fiber reinforced composites respectively by maintaining 2:3 and 3:2 proportion of resin: reinforcement. The prepared composites were tested for their mechanical properties and resistance toward various chemicals.     

改性酚醛树脂的合成及应用研究

本文介绍用腰果壳油与苯酚、甲醛反应，在复合催化剂存在下，用一步法制得改性酚醛树脂。该树脂具有热分解温度高，韧性好等特性，用此树脂与蛭石等材料复合制成的摩擦材料，具有耐温、耐磨、冲击性能好等特性，是有机基摩擦材料较理想的粘结剂。     

Preparation of cardanol–formaldehyde resins from cashew nut shell liquid for the reinforcement of natural rubber

Natural rubber was reinforced with a high loading of a cardanol–formaldehyde resin prepared from cashew nut shell liquid. Cardanol–formaldehyde resins, both resoles and novolaks, were synthesized from cardanol, which was extracted from cashew nut shells. This was done by the condensation polymerization of cardanol and formaldehyde in the presence of base and acid catalysts. The cardanol–formaldehyde resole with the highest yield (ca. 75%) was prepared with a formaldehyde/cardanol molar ratio of 2.0 at pH 8.0 and 90°C for 8 h. The cardanol–formaldehyde novolak with the highest yield (ca. 80%) was prepared with a formaldehyde/cardanol molar ratio of 0.8 at pH 2.2 and 100°C for 7 h. Fourier transform infrared and ¹³C‐NMR were employed to characterize the chemical structures of the obtained cardanol–formaldehyde resins. The resins were compatible with natural rubber in various formulations. The cured behaviors of natural rubber blended with the cardanol–formaldehyde resole and novolak resins were investigated. The cured behaviors of cardanol–formaldehyde resole and cardanol–formaldehyde novolak samples were different, reflecting differences in their chemical reactivities. Furthermore, the incorporation of cardanol–formaldehyde resins into natural rubber provided significant improvements in mechanical properties such as the hardness, tensile strength, modulus at 100 and 300% elongation, and abrasion resistance. However, the elongation at break and compression set of the blends decreased as expected. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1997–2002, 2007     

Fabrication and evaluation of some mechanical and electrical properties of jute‐biomass based hybrid composites

Hybrid composites based on bisphenol‐C‐formaldehyde resin and jute mat with rice, wheat, sugar cane, and jamun husks have been fabricated at 150°C under 30.4 MPa pressure for 2 h. The resin content in composites was 50% of fibers. Tensile strength, flexural strength, electric strength, and volume resistivity of hybrid composites have been evaluated and compared with those of jute‐bisphenol‐C‐formaldehyde composites. It is observed that the tensile strength of composites is found to decrease by 53–72%, which is mainly due to random orientation of sandwiched fibers. Flexural strength has increased by 53–153% except jute–rice husk composite for which it is decreased by 26%. A little change in dielectric breakdown strength (1.89–2.11 kV/mm) is found but volume resistivity of Jute–wheat husk and Jute–jamun husk composites has improved by 437–197% and it is slightly decreased(2.3–25.2%) for the remaining two composites. Thus, hybrid composites possess good mechanical and electrical properties signifying their importance in low strength and light weight engineering applications as well as low cost housing units such as partition and hard boards. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1754–1758, 2006     

Recycling of jute textile in phenol formaldehyde–jute composites

Jute textile was recycled into composites using different percents of phenol formaldehyde (PF) resin. The effect of the resin percent, from 12 to 30%, on the flexural strength, tensile strength, water absorption, and thickness swelling of the produced composites was studied. To improve the dimensional stability of the produced composites, jute textile was acetylated or steamed. The effect of steaming and acetylation on the structure and thermal stability of jute fibers was studied using Fourier Transform Infrared (FTIR) spectroscopy and Thermogravimetric analysis (TGA), respectively. The effect of these treatments on the flexural strength, tensile strength, water absorption, and thickness swelling of the produced composites was studied. Steaming of jute textile was superior to acetylation in improving the dimensional stability. Cyclic wetting and drying test of the composites showed that steaming of the jute textile resulted in much less irreversible and reversible thickness swelling than in case of using acetylated or untreated jute textile. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3588–3593, 2003     

腰果壳油在高分子材料中的应用研究进展

阐述了腰果壳油结构与性能的关系,综述了近几年来国内外腰果壳油在高分子材料方面的应用,其中包括作为酚醛树脂改性剂、橡胶增塑剂以及在涂料和粘合剂方面的应用。     

1,3‐bis(benzoxazine) from cashew nut shell oil and diaminodiphenyl methane and its composites with wood flour

Cashew nut oil‐based benzoxazine monomer has been synthesized applying solvent‐less method through the Mannich reaction of cashew nut shell oil as phenol, amine, and formaldehyde. A difunctional 1,3‐benzoxazine is synthesized using diaminodiphenyl methane as the amine component. ¹H and ¹³C‐nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy are used to characterize the structure of the monomers. Wood flour is used to prepare composites, making both reinforcement and matrix resin the materials derived from renewable resources. Observation of catalytic effects on DSC exothermic temperature and crosslink density by the added wood flour is discussed. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

高固体分酚醛环氧涂料的研究和设计

以液体酚醛环氧树脂为主基料树脂,脂肪酸改性环氧树脂为辅助基料树脂;以改性芳香胺、改性脂环胺、腰果壳油改性酚醛胺为固化剂制备了高固体分酚醛环氧涂料,该产品能够适用于更苛刻的腐蚀环境。还研究了不同固化剂及当量比对涂层物理化学性能的影响,并展望了该产品的应用前景。