Synthetic resins: XV. Chelation ion exchange properties of 2,4- dinitrophenylhydrazone of resacetophenone-formaldehyde resin

A number of copolymers were synthesised by condensing the 2,4-dinitrophenylhydrazone of resacetophenone with substituted benzoic acids/ phenols and formaldehyde in the presence of sodium hydroxide or hydrochloric acid. The decomposition temperature, solubility and viscosity of the polymers have been determined. The ion-exchange properties have been studied by using a batch equilibrium method. The distribution of a number of metal ions between an aqueous solution and the resin have been measured. A wide range of pH and variable ionic strengths have been investigated.     

稀土树脂相分光光度法研究

在HCl—KCl(pH0.5)介质中,稀土—三溴偶氮胂二元络合物能较好地被阴离子交换树脂吸附。RE_2O_8在0～8μg/25ml范围内符合比尔定律,以双波长等吸收点法(测量波长λ_1=650nm,参比波长λ_2=740nm)扣除树脂背景影响,应用于稀土矿中稀土总量测定,结果令人满意。     

Microstructure-related fracture toughness and fatigue crack growth behaviour in toughened, anhydride-cured epoxy resins

Fracture toughness and fatigue crack propagation (FCP) of plain and modified anhydride-cured epoxy resin (EP) were studied at ambient temperature. Liquid carboxyl-terminated acrylonitrile-butadiene (CTBN) and silicon (SI) rubber dispersions were used as tougheners for the EP. The morphology of the modified EP was characterized by dynamic mechanical analysis (DMA) and by scanning electron microscopy (SEM). The fracture toughness, K_c, of the compositions decreased with increasing deformation rate. K_c of the EP was slightly improved by CTBN addition and practically unaffected by incorporation of the SI dispersion when tests were performed at low cross-head speed, v. Both modifiers improved K_c at high v, and also the resistance to FCP, by shifting the curves to higher stress intensity factor ranges, ΔK, by comparison with the plain EP. It was established that both fracture and fatigue performance rely on the compliance, J_R, at the rubbery plateau, and thus on the apparent molecular mass between crosslinks, M_c. The failure mechanisms were less dependent upon the loading mode (fracture, fatigue), but differed basically for the various modifiers. Rubber-induced cavitation and shear yielding of the EP were dominant for CTBN, whereas crack bifurcation and branching controlled the cracking in SI-modified EP. The simultaneous use of both modifiers resulted in a synergistic effect for both the fracture toughness at high deformation rate and the FCP behavior.     

树脂热解炭制备碳化硅晶须

用自制的配合醛树脂热解和炭源，用ＳＩＯ２超细汾作原，根据碳热还原原理，利用常规加热和微波加热两种方式，分别制备了直径在纳米级的ＳｉＣ晶须，Ｘ射线衍射、透射电检测结果表明：制备工艺和条件对ＳｉＣ晶须的性质有较大的影响。     

苯胺衍生物改性酚醛树脂的性能和结构表征

选用某种叔胺类化合物作苯酚和甲醛反应的催化剂,并加入少量苯胺衍生物,制备了一种分子量较高的改性酚醛树脂。根据IR、NMR和GPC的测试分析,对苯胺衍生物改性酚醛树脂的结构特征等进行了研究。它与环氧树脂合成压制的玻璃布层压板的浸水后绝缘电阻可达1011Ω以上,其它主要性能也达到了国外同类产品水平。     

己二酸二乙酯合成新工艺的研究

本文以离子交换树脂作为液固相酯化反应的催化剂 ,甲苯作为带水剂 ,合成己二酸二乙酯。应用本法 ,酯化反应产率高达 78%。同时对影响产率的诸因素进行了考察 ,其最佳反应条件为 :酸醇摩尔比 1∶4 ,催化剂用量为酸质量的 2 5 % ,反应时间为 10小时 ,反应温度 86～ 87℃ ,催化剂重复使用 4次 ,未出现活性明显下降 ,此工艺操作简单 ,反应条件温和 ,产率高 ,具有显著的工业应用价值。     

丙烯酸酯与甲基丙烯酸酯的共聚及性能研究

采用悬浮聚合法，以丙烯酸－２－乙基－己酯与甲基丙烯酸十二酯为单体，合成了共聚型高吸油性树脂。研究了共聚单体的配比、交联剂用量、引发剂用量诸因素对高吸油性树脂的性能影响。制得的树脂可以吸其自身质量的１１．８倍的煤油、１４．７倍的苯、６．５倍的泵油。     

Changes in the dielectric relaxations of water in epoxy resin as a function of the extent of water ingress in carbon fibre composites

Dielectric relaxation measurements are reported over a frequency range from 10⁻¹ to 10⁹ Hz as a function of exposure time for an epoxy resin-carbon fibre composite, ageing at 60 °C in water. Investigation of the nature of the dipole relaxation of the water molecules, indicates the nature of their interaction with the polymer matrix. Analysis of the dielectric relaxation spectra allow identification of processes that can be attributed to ‘free’ and ‘bonded’ water, water in micro-cracking, located in carbon fibre disbonds and plasticizing the polymer matrix. Identification of the various types of location in which water exists was aided by use of the N_g factor from the Kirkwood-Frölich equation, which describes the constraints on free dipole ration nature imposed by the environment in which it is located. These data indicate the power of the dielectric technique for quantitative analysis of water ingress into epoxy composites.     

常温冲孔性优良的CEM-1覆铜板的研制

本文介绍了一种CEM-1覆铜板的制作方法,采用这种方法制作的覆铜板具有优良的常温冲孔性和良好的性价 比。     

Characterization of resol resins modified by the addition of PVC plastisols

Plastisols, which are a blend of poly(vinyl chloride) resin and a plasticizer (DEHP), were used as a toughening agent of a resol resin in order to improve the mechanical properties. It was not possible to formulate resol blends by adding more than 10 % of plastisol owing to a lack of apparent homogeneity in the systems, which also showed many air bubbles. The relationship between dynamic mechanical, mechanical and thermal properties and the amount of plastisol added was studied. It was determined from the infrared spectroscopy and dynamic mechanical results that the resol–plastisol blends seem to be formed by a reaction between the phenol and PVC giving a higher crosslinked structure. An improvement in the thermal resistance of the blends at lower temperatures was observed with an increase in the percentage of plastisol. Flexural analysis showed the elastic behaviour of the systems. However, it was not possible to observe the effect of the plasticizer (DEHP) owing to the low quantity of plastisol that was added to the resol. Copyright © 2004 Society of Chemical Industry