橡胶补强用酚醛树脂的研究

对橡胶补强用酚醛树脂的合成方法、反应原理、工艺条件、性能鉴定等予以较详细的讨论,认为该类酚醛树脂是现代子午线轮胎和其它橡胶制品重要而理想的补强剂。     

橡胶增硬剂——酚醛补强树脂

介绍了一种用于橡胶增硬的酚醛补强树脂。研究了酚醛补强树脂用量对ＮＲ和ＳＢＲ的物理性能及工艺和硫化特性的影响。结果表明，酚醛补强树脂对硫化胶具有较高的增硬效果，同时可改善胶料加工特性和流动性，降低混炼能耗，是一咱综合性能较好的补强增硬剂，适合于在子午线轮和其它橡胶制品中推广使用。     

橡胶补台用酚醛树脂

树脂补强的橡胶胶料,能增加硬度和模数值,影响粘弹性有关性能,影响决定于弹性体性质,树脂与硬化剂比率和填充剂用量,结果说明树脂,填充剂和弹性体之间的相互作用。     

新型改性酚醛补强树脂PF-C在全钢子午线轮胎胶料中的应用

研究了新型改性酚醛树脂ＰＦＣ对ＮＲ的补强效果,以及对胶料性能及硫化胶物理性能的影响,并与国内３ 个生产厂家的酚醛补强树脂进行了对比。结果表明,加入ＰＦＣ或普通酚醛树脂后,可产生较高的增硬效果,同时硫化胶的定伸应力和扯断永久变形增大,但胶料的门尼粘度升高,焦烧时间缩短,硫化速度减慢,其中ＰＦＣ的增硬效果最佳,对胶料的硫化特性影响最小,胶料的综合性能最优。     

炼铁废渣制取TGLZ橡胶补强填充剂补强机理的研究

针对目前橡胶填充剂炭黑价格上浮,提高了橡胶制品成本的情况,利用炼铁废渣研制TGLZ(涂敷高炉炼铁废渣)无机橡胶补强填充剂。通过炼铁废渣干燥、除铁、粉碎、分级、冷敷、冷却等工序制得成品。对TGLZ橡胶补强填充剂的补强机理进行研究。试验结果表明,通过320目筛的TGLZ及选用钛酸酯偶联剂作TGLZ的表面处理剂,都对橡胶有优良的补强作用。该补强剂的研制,既节约了炭黑资源,又解决了环境污染问题。     

酚醛树脂对农业轮胎胎面胶的补强作用

本研究对酚醛树脂在农业轮胎胎面胶中的补强作用进行了考察。结果发现,与较软的对比胎面胶相比,添加清漆酚醛树脂胎面胶的硬度大大提高,撕裂性能和耐屈挠龟裂性能也有所改善,而且工艺性能并未受到损害。酚醛树脂在橡胶工业中的应用已经有很长一段历史了。它主要被用作...     

Alkylated phenolic resins as antioxidants for rubber

Polymeric antioxidants based on p‐nonyl phenol formaldehyde resin (PNPF) and p‐dodecyl phenol formaldehyde resin (PDPF) were prepared by the condensation reaction of the respective phenols with formaldehyde in the presence of an acid catalyst. The reactions were monitored by thin layer chromatography, and the melting points of the products were determined. These compounds were incorporated in natural rubber mixes to evaluate their antioxidant properties. The compounded mixes were characterized for their rheometric properties. The compression‐molded rubber sheets were tested for their mechanical properties. The effects of aging on the mechanical properties of these molded sheets were evaluated. Both PNPF and PDPF showed better antioxidant properties than the conventional styreneated phenol antioxidant. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2649–2651, 2006     

Optimization of phenolic resins for friction materials

The physicomechanical properties of phenolic composites containing a large amount of mineral fillers were enhanced through a chemical modification of the basic resin. Various phenolic compounds were first introduced in the condensation mixture leading to modified novolaks, but the final properties of the resulting composites were only slightly improved. Better results were obtained using an optimum content of epoxy-novolak or melamine in the last stage of processing as confirmed by static and dynamic mechanical analysis. The new procedure introduced recently by Halpin and Sendeckyj for fitting fatigue models was applied to our particle-filled material. The results confirm the reinforcement of the composite through the co-reactivity of phenolic resins with the introduced species in the final curing stage.     

Graphitization of phenolic resins for carbon-based refractories

The chemical resistance and thermo-mechanical properties of refractories bonded with resole or novolak resins depend on the presence of crystalline carbon phases (preferentially with features close to graphite ones) in their compositions. Although thermosetting resins are commonly classified as non-graphitizing carbon sources, many efforts have been made in recent years in order to find effective routes to induce the in situ graphitization of such components in refractory products during service. This work evaluates the role of processing parameters (mixing, curing and firing temperature) and additives (ferrocene, boric acid and exfoliated graphite) in the graphitization process of two commercial resins (resole and novolak) and a synthesized one (modified-novolak). X-ray diffraction, Raman spectroscopy and thermogravimetric analyses were carried out to identify the microstructural evolution of the compositions. According to the results, carbon graphitization was already detected after firing the samples at 1000 °C for 5 h under reducing atmosphere. Ferrocene addition favored a more effective graphitization of the selected resins, but H₃BO₃ also induced the rearrangement of the carbon derived from the commercial novolak product. The mixing and curing procedures used when preparing the compositions proved to be very important steps as they affected, to a greater extent, the resulting graphitization degree of the fired samples.     

Boron-modified phenolic resins for high performance applications

A boron-modified phenolic resin (BPR) that flows at usable processing temperatures was prepared from the solvent-less reaction of triphenyl borate (TPB) and paraformaldehyde (PF). The reaction of TPB and PF was performed at three different resinifying temperatures, 130, 120 and 90 °C. The BPR produced at 90 °C melted upon reheating, which indicated promising processing applications for this resin. ¹H and ¹³C NMR spectra of resins from the three resinifying temperatures had the same pattern of absorptions. Substitution of methylol groups occurred at the ortho and para positions of the ester phenyl rings (4.86-4.75 ppm). Aromatic, methylene and ether linkage protons were assigned at about 7.45-6.74, 4.93-3.36 and 5.30-4.91 ppm, respectively. The synthesis of BPR from the reaction phenolic resins, produced under basic conditions (resoles) and boric acid was not feasible. The reactivity of the resoles species with each other is more favorable than that with boric acid.     

酚醛树脂固化动力学研究

采用DSC方法探讨了酚醛物质的量比(F/P)为1.3、1.5、1.8的酚醛树脂的固化反应过程。在50~300℃温度范围内以不同升温速率(5、10、15、20℃/min)进行动态固化行为分析。运用Kissinger和Ozawa法进行了动力学研究,得到其固化反应活化能。结果表明:两种方法计算得到活化能的大小顺序是一致的。高物质的量比酚醛树脂在固化过程中具有的活化能比低物质的量比酚醛树脂的要低,这就意味着高物质的量比酚醛树脂固化时需要较少热量。因此,酚醛树脂的F/P物质的量比越高,固化反应的活化能就越低。随升温速率提高,该种树脂的起始固化温度Ti,峰顶固化温度Tp,终了固化温度Tf都有提高,同时固化时间tc缩短。     

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     

In‐situ polymerized phenolic resin for reinforcement of chloroprene and ethylene–propylene rubber vulcanizates

Phenolic resin (PF) was incorporated into rubbers by in situ polymerization at the vulcanization conditions of rubbers. The PF with a localized three‐dimensional network structure was formed in chloroprene rubber (CR), whereas the fabric PF was formed in ethylene–propylene rubber (EPDM). The study results showed that the PF phase was effective on reinforcing these rubbers. Depending on the morphologies of the formed PF phases, various rubber properties could be significantly enhanced. In the case of CR rubber, the tensile strength, tear strength, and modulus could be considerably enhanced, but the elongation and resilience properties were limitedly affected by PF addition. For EPDM rubber, all mechanical properties were improved, particularly the elongation, about 26% increase. The substantial improvements of mechanical properties of CR and EPDM rubbers were attributed to their morphology, high flexibility, moderate stiffness, and excellent bonding with rubber matrix. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

橡胶的织物增强

从织物的增强性能角度出发,论述了对橡胶复合结构的增强条件。说明不同的织物材料、结构形式和工艺过程对最终的合成橡胶制品性能有影响,从而通过对织物的改性和正确选择,达到提高橡胶制品强度的目的。     

Tailoring the polymeric nanoparticles for rubber reinforcement

Polymeric nanoparticles with brush‐like polydiene as the shell and crosslinked polystyrene as the core are synthesized using anionic polymerization via a self‐assembly process of macromolecules in solutions. The microstructures of nanoparticles were designed to match those of the matrix polymer used for tire compounds. Desirable compound properties were obtained by tailoring the shell sizes of the nanoparticles. Depending on the core/shell structures of the nanopartilces, the addition of the nanosized particles may impart the compound ultimate physical properties. Well reinforced compounds with enhanced dynamical storage modulus (G′) without increasing their dependences on temperature and deformation strain can be obtained by the addition of the nanoparticle with lengthened shell chains. Improved tensile mechanical properties without increasing high‐temperature hysteresis were also attained by such reinforcement. Passenger and truck tire applications can be advantageously benefited from these properties with improved tire handling and cornering consistence without increasing the rolling resistance and the sacrifices of other performances. A miscibility study was conducted on various binary blends of nanoparticle and rubber matrix. The compatibility between the nanoparticle and the matrix rubber along with the core concentration were demonstrated to be responsible for the observed improved compound properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Structural analysis of phenolic resole resins

The chemical structure and cure characteristics of a group of phenolic resole resins were studied by means of three major analytical techniques. In particular, the effects on structure and reactivity of formaldehyde/phenol ratio and the type of reaction catalyst used were studied. Gel permeation chromatography was used to determine resin molecular weight distributions, and NMR, to determine chemical structural features. In this connection a selective oxidation procedure, converting free methylol groups to adehydes, has allowed unambiguous determination of methylene ether bridge structures to be made from the NMR data. The F/P ratio in a resole largely determines the type of molecular structures which are formed. However, triethylamine as a catalysts tends to favor methylene ether bridge formation, whereas sodium hydroxide favors methylene bridges. The rate and direction of subsequent thermal cure of the resoles prepared is shown by differential scanning calorimetry to depend markedly on the type of catalyst present during the curing stage. The DSC curing curves are interpreted in the light of the structural information provided by NMR.