Polyfunctional epoxies: Part I. rubber-toughened brominated and nonbrominated formulations for graphite composites

A new trifunctional epoxy resin, Tris-(hydroxyphenyl)methane triglycidyl ether, was compared to a state-of-the-art resin, 4,4′-diaminodiphenyl methane (TGDDM), in graphite composites. Rubber-toughened brominated and nonbrominated formulations were compared for their mechanical performance, environmental stability, thermochemical behavior, and flame retardancy. It was found that the new resin performs almost the same way as the TGDDM does, but has some improved properties. The fracture toughness of the various formulations was studied carefully and the overall performance of the new resin is discussed.     

Characterisation of a bisphenol a epoxy resin. A collaborative study carried out by technical panel PTP3 of the technical cooperation programme

A collaborative study has been made by a number of laboratories of samples of nominally the same bisphenol A epoxy resin prepared in different countries and its cure with diaminodiphenylsulphone. A variety of techniques have been used to characterise the resin samples and their relative value for structural analysis and specification purposes assessed. Physical and mechanical properties of cured cast resin samples have also been measured and related to the resin structures observed. The study shows that some of the techniques do indicate differences in resin composition, but that these were not reflected in differences in mechanical properties.     

硼酚醛改性BMI树脂的研究

在传统的4,4－双马来酰亚胺基二苯甲烷／二烯丙基双酚A体系中引入硼酚醛结构,以改善传统双马来酰亚胺（BM）树脂的燃烧性能,结果表明,在一定范围内随着硼酚醛结构含量的增加,明显提高了BMI体系在空气中的热分解温度,改善了BMI体系的燃烧性能,而原BMI体系的工艺性能及力学性能保不变。     

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.     

强酸性树脂催化合成乙酸异戊酯

以均匀设计安排实验,在强酸性阳离子交换树脂催化剂的作用下,快速合成了乙酸异戊酯,实验结果经过优化组合,得出最佳反应条件为:异戊醇与冰乙酸物质的量的比为0.75,催化荆重复次数为10次,回流时间为1.7 h.同时,对树脂的重复使用性能进行了测试,结果表明:树脂在使用10次后,其催化性能保持不变.     

Reversible crosslinking in epoxy resins. I. Feasibility studies

The objective of the research is to investigate epoxy resins where crosslinks formed in curing reactions can be cleaved and reformed without significant sacrifice in resin properties. In this phase of the investigation, experimental disulfide-containing crosslinking agents have been studied, including dihydrazides of dithiodicarboxylic acids(aliphatic and aromatic) and dithio-aromatic diamines. Conditions for curing reactions and for subsequent cleavage of crosslinks by reduction have been determined in model systems and confirmed for a prototype epoxy resin. A preliminary comparative evaluation of cure kinetics and of crosslink density and thermal and mechanical properties has been carried out for this resin cured with aromatic curing agents (4,4′-dithiodianiline and methylene dianiline) and with aliphatic compounds (3,3′-dithiopropionic acid dihydrazide and hexamethylene diamine). It has been shown that in a resin fully cured with disulfide-containing crosslinking agents, crosslinks could be ruptured by reduction, and reestablished by oxidation under mild conditions.     

Chemorheology of thermosetting resins. II. Effect of particulates on the chemorheology and curing kinetics of unsaturated polyester resin

The effect of particulates on both the rheological properties during cure and the curing kinetics of unsaturated resin has been investigated. For the investigation, a general-purpose unsaturated polyester resin was used, with calcium carbonate and clay as inorganic particulates and high-density polyethylene powder as organic particulates. It has been found that, as the particulate content increases, the resin/particulate mixture gives rise to shear-thinning behavior and the rate of cure increases. It has also been found that the CaCO₃ particles helped control shrinkage during cure when the material was subjected to steady shear deformation and that the gel time tη∞ is shorter for mixtures of resin and particulates than for the neat resin alone. Differential scanning calorimetry (DSC) is found useful for determining the curing kinetics of resin/particulate mixtures. We have combined rheological and DSC measurements to obtain a correlation between viscosity and the degree of cure during isothermal curing operations.     

Oil well sand consolidation. I. Resins for a three-step process

Oil-bearing formations often consist of loose sandy material. In the production of oil from these formations sand tends to be carried to the well bore along with the oil. The flow of sand can be prevented by consolidating or cementing together the sand particles of the formation around the well bore. The cementing has to be accomplished in such a manner that fluid flow channels between particles remain open. This paper describes a new three-step process that was developed to consolidate oil well sand. The steps in the process involve injection of: (1) resin, (2) inert fluid, and (3) inert fluid containing a catalyst. In the first step of the process, resin in injected into the formation where it fully saturates the interstices between sand grains. Permeability is established in the second step by displacement of the excess resin from the interstices, thereby leaving a thin film of resin on the sand grains. In the third step, polymerization is activated by migration of catalyst from the inert fluid into the thin resin film on the sand. The process has the advantage that resin is placed and permeability is established before the resin is catalyzed. This avoids premature polymerization of the resin which might cause plugging of the formation or the tubing string used to inject resin. Desirable characteristics of a resin for the three-step process are: (1) viscosity of 25–200 cp. at well bore temperature; (2) stability for several days at well bore temperature; (3) high adhesion to sand in the presence of an inert flushing fluid; (4) polymerization by less than 10% catalyst; (5) the polymerized resin binds sand together with a strong bond that is not affected by well fluids. Five different resin types have been tested for use in the three-step sand consolidation process. These are: (1) epoxy–anhydride cured with a tertiary amine; (2) epoxy–epoxy diluent cured with a primary–tertiary amine mixture; (3) furan; (4) unsaturated polyester–vinylpyrrolidone; (5) unsaturated polyester–styrene. The two epoxy resins give strong, permeable consolidated sand which is resistant to well fluids such as brine and crude oil. The furan resin gives a weak consolidation. The unsaturated polyester–vinylpyrrolidone gives good strength and oil resistance but is sensitive to brine. The unsaturated polyester–styrene is difficult to apply. Many oil wells have been successfully treated in the Gulf Coast area and in California with the two epoxy resins. Almost all of these wells are producing free of sand, and, to date, more than five million barrels of oil have been produced from these wells.     

Resin transfer molding of natural fiber reinforced polybenzoxazine composities

Kenaf fiber is incorporated in a polybenzoxazine (PBZX) resin matrix to form a unidirectionally reinforced composite containing 20 wt% fiber by a resin transfer molding technique. Two types of benzoxazine monomer are synthesized and used as resin mixtures: Benzozazines based on bisphenol‐A/aniline (BA‐a) and phenol/aniline (Ph‐a). The effects of varying BA‐a:Ph‐a ratio in the resin mixture and curing conditions on mechanical properties of pure PBZX resin and kenaf/PBZX composites are studies. The Flexural strength of the pure PBZX resin increases with increasing ratio of BA‐a:Ph‐a, curing temperature and curing time, but the impact strength increases only slightly. PBZX resin has lower water absorption and higher flexural modulus, when compared with unsaturated polyester (UPE) resin. PBZX composites with 20 wt% fiber content have lower flexural and impact strengths, but higher moduli compared with UPE composites with the same fiber content.     

线形高分子量聚苯硫醚树脂的合成研究

以硫磺和对二氯苯为原料,在极性有机溶剂中,用以羧酸盐为主的复合催化体系成功地合成了高分子量ＰＰＳ树脂。合成的ＰＰＳ树脂经红外光谱分析,激光拉曼光谱分析,Ｘ－射线衍射分析以及热分析后表明,该树脂与日本吴羽化学工业公司第二代线形高分子量ＰＰＳ树脂Ｆｏｒｔｒｏｎ具有相同的结构和性质,为线形高分子量ＰＰＳ树脂。该树脂具有分子量高,熔融粘度低,加工时几乎不变色等特点。     

Curing and post‐curing luminescence in an epoxy resin

A spontaneous luminescence is reported when epoxy resin samples are heated in air. This phenomenon is very sensitive to the nature of the atmosphere. The same treatment in nitrogen leads to an extinction of the luminescence. The emission process is restored when samples are kept for a sufficient time in air. To better understand this phenomenon, we have investigated the luminescence of the elementary constituents of the epoxy (resin and hardener), when heated in air and nitrogen, as well as during resin‐curing in the same atmospheres. It appears that the emission process is linked with the presence of oxygen. Although the kinetics of the luminescence can differ, depending on the nature of the sample (cured resin, resin during curing, liquid components), the emission spectra are the same during resin‐curing and upon heating of the cured resin and hardener. The emission spectrum of the base resin is different. It is concluded that the light results from a chemiluminescence process during oxidation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1899–1904, 2006     

Emulsification and electrodeposition of mixtures of cationic resins. I. Cationic resin and nonionic cross-linker

The emulsification and electrodeposition properties of two resins system (cationic epoxyamine adduct, III , was the main resin; nonionic trimethylolpropane–toluene diisocyanate-2-ethylhexanol resin, II , was used as cross-linker) were investigated and the compositions of their electrodeposited films were obtained by Fourier transform infrared (FTIR) quantitative analysis to study the coemulsion and electrophoretic behaviors. The optimum resin compositionof coemulsion was also found to provide the deposited film having the best properties. The results indicate that the molecules of nonionic cross-linker II are entangled by the ones of cationic resin III during the dispersion process and they can be codeposited on the cathodic substrate after a voltage has been applied. Moreover, at the condition of stable coemulsion of the two-component system, the resin composition of electrodeposited film is almost equal to the resin composition of the coemulsion and is not affected by the applied voltage or resin concentration. © 1993 John Wiley & Sons, Inc.     

中国合成树脂产业面临的机遇与挑战

近年来,我国五大合成树脂行业迎来战略机遇期,发展迅速:一方面国内外经济回暖趋好,下游产品需求增强,拉动我国合成树脂表观消费增长;另一方面由于近年来国际油价低位震荡及北美聚烯烃大量新建产能尚未投产,亚洲地区聚烯烃和石脑油价差增大,毛利提高,在一定程度上推动我国合成树脂新建项目投资。未来我国合成树脂行业将面临战略机遇与转型升级压力并存局面:一方面随着城镇化、农业现代化不断推进及"禁废令"等政策的出台,产业结构升级及消费潜力释放将持续带动树脂需求增长;另一方面我国树脂行业也将承压来自北美、中东新增廉价产品大量出口。与此同时,消费结构升级对于合成树脂高端化需求愈发提高,我国树脂行业整体偏低端化、结构不合理等问题也将愈发明显,转型升级已是刻不容缓。综合来看,我国合成树脂行业机遇与挑战并存,如何有效抓住机遇、合理应对挑战将是我国树脂行业需要思考的重要课题。     

Rheology of unsaturated polyester resins. III. Effects of filler and low-profile additive on the thickening behavior of unsaturated polyester resin

An investigation was made of the rheological behavior of unsaturated polyester resin during thickening in the presence of filler or low-profile additive alone and, also, in the presence of both filler and low-profile additive. For the study, two different types of filler (CaCO₃ and clay) and two different types of low-profile additive (PMMA and PVAc) were evaluated. Compared to the resin/thickener system, the resin/filler/thickener system exhibits shear-thinning behavior as thickening progresses, and gives rise to smaller normal stress effects. On the other hand, the resin/low-profile additive/thickener system exhibits two distinct Newtonian regimes in the viscosity-shear stress curves and gives rise to larger normal stress effects. The viscosity behavior of the resin/filler/low-profile additive/thickener system was found to be very similar to that of the resin/low-profile additive/thickener system. In all cases, when the first normal stress difference was plotted against the shear stress, a correlation was obtained which was independent of thickening period. This behavior was exactly the same as for thickening polyester resin alone, as discussed in Part II of this series.     

挠性覆铜板用无卤阻燃环氧树脂及其固化剂的研究进展

为了适应无卤无铅绿色环保发展要求,挠性覆铜板(FCCL)的环保性能越来越受到大家的重视。目前FCCL最常用的材料为环氧树脂胶黏剂,虽然添加型阻燃剂能达到阻燃效果,但是对力学性能影响很大。所以,反应型的环氧树脂及其固化剂的无卤化是FCCL无卤化的两个重要方面。综述了近年来国内外在无卤阻燃环氧树脂(含磷、含硅、含氮环氧树脂及苯酚-芳烷基型自熄性环氧树脂)及其固化剂(含磷、含硅固化剂,含氮酚醛树脂和苯酚-芳烷基型环氧树脂固化剂)的研究进展,并对其今后的发展做一展望。     

Moisture diffusion in epoxy resins Part I. Non-Fickian sorption processes

Diffusion of water in a glassy epoxy resin has been studied by the sorption method. Film thickness scaling is used as a diagnostic tool for non-Fickian sorption processes. A sorptiondesorption cycle effectively increases the preexisting free volume in the resin and renders the subsequent sorption process different from the original. The effect is understood by considering the time scale for diffusion and that for molecular relaxation of the glassy polymer network. A non-Fickian sorption process is observed for an insufficiently cured resin and is caused by the resin undergoing further postcuring in the sorption process. It is shown that oxidation of the resin during sorption also gives rise to non-Fickian processes previously described in the literature as diffusion anomalies for epoxies. It is further shown that the difference between sorption and resorption curves is not caused by irreversible damage to the resin but due to reversible changes in network conformations.     

UPTAKE OF METAL IONS BY A NEW CHELATING ION EXCHANGE RESIN. PART 8 : SIMULTANEOUS UPTAKE OF CATIONIC AND ANIONIC SPECIES* *

ABSTRACT

The uptake of tri-, tetra- and hexa-valent actinides as well as of pertechnetate anions by some new multifunctional ion exchange resins has been investigated. The new resins, identified as Diphonix A, for anionic Diphonix, contain the same geminally substituted diphosphonic acid groups bonded to a styrenic-based polymer matrix as the regular Diphonix resin, plus strong base anion exchange groups such as the tetraalkylammonium (Diphonix A - Type 1 resins) or the quaternized pyridinium (Diphonix A - Type 2 resins) groups. Our uptake measurements have shown that the Type 2 Diphonix A resins are as effective as the regular Diphonix resin in the rapid uptake of actinides from acidic solutions, while at the same time sorbing pertechnetate anions in a manner comparable to existing commercial anion exchange resins. The failure of the Type 1 Diphonix A resins to perform equally well has been explained as a consequence of the mutual interaction of adjacent diphosphonic acid groups and tetraalkylammonium groups. Uptake data have also been obtained with Se(IV). The behavior of the Diphonix A resins toward Se(IV) uptake in acidic solutions is comparable to that of commercial anion exchange resins.     

酚醛树脂对均相成核的中间相炭微球生成的作用

在QI含量很低的沥青中加入适量的酚醛树脂，可以改变沥青生成中间相炭微球的热缩聚反应，进而改变中间相炭微球的形貌与微观结构。酚醛树脂在沥青稠环芳烃分子热缩聚过程的初期形成共晶，在后期充当炭微球的交联剂的作用，使中间相炭微球的收率增加，尺寸变大，并影响了中间相炭微球的织构，红外光谱分析表明酚醛树脂已参与了中间相炭微球的形成；偏光显微镜、扫描电镜形象地表征出了中间相炭微球的微观织构以及酚醛树脂的作用。     

聚脲基氨酯增强增韧环氧树脂的研究

用原位多相聚合法合成了聚脲基氨酯/环氧树脂互穿聚合物网络（IPN）,测定了产物的力学性能和热性能。探讨了IPN中聚脲基氨酯含量对环氧树脂增韧过程的影响,结果表明,对于N,N-二甲基苄胺固化体系,加入12.0phr的聚脲基氨酯,在不降低其热稳定性的同时,可使环氧树脂冲击强度提高35%左右,拉伸强度提高12%～15%;对于4,4＇-二氨基二苯砜或4,4＇-二氨基二苯甲烷固化体系,加入12.0phr的聚脲基氨酯可使环氧树脂冲击强度提高92%左右,拉伸强度提高20%～24%。     

Intercalation of epoxy resin in organically modified montmorillonite

Various methods of preparation of epoxy resin/clay mixtures, before the addition of the crosslinking agent and curing to form epoxy‐based polymer layered silicate (PLS) nanocomposites, have been investigated to determine their effect on the nanostructure. Organically modified montmorillonite clay was used, and the mixtures were prepared by both simple mixing and solvent‐based methods. X‐ray diffraction shows that intercalation of the resin into the clay galleries occurs for all clay loadings up to 25 wt % and for both preparation methods, but the dispersion of the clay in the resin, observed by optical microscopy, is significantly better for the solvent preparation method. Differential scanning calorimetry (DSC) shows that the intercalated resin has the same molecular mobility as the extra‐gallery resin, but suggests that the intercalated resin does not penetrate completely into the galleries. Prolonged storage of the resin/clay mixtures at room temperature leads to changes in the DSC response, as well as in the response to thermogravimetry, which are interpreted as resulting from homopolymerization of the epoxy resin, catalyzed by the onium ion in the modified clay. This confirms and explains the earlier observation of Benson Tolle and Anderson (J Appl Polym Sci 2004, 91, 89) that “conditioning” of the resin/clay mixtures at ambient temperature has a significant effect when the crosslinking agent is subsequently added, and indicates that the preparation method has important consequences for the nanostructure development in the PLS nanocomposites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:3751–3763, 2006