Characterization and properties of poly(ethylene oxide) and its blends with poly (N-vinyl carbazole)

The calorimetric properties and dynamic mechanical behaviour of pure poly(ethylene oxide) (PEO) and its blends with poly(N-vinyl carbazole) (PNVK) have been examined as a function of composition in the range 50-100% PEO. Thermomechanical measurements indicate the presence of a phase separation in this blend. Using the Hoffman-Weeks plot no equilibrium melting point depression was found in any of the blends studied. Some kinetic interfacial effects were detected in the crystallization processes. For all blend compositions, the Avrami exponent is close to that obtained for pure PEO. The DMTA and DTA results suggest an incompatibility in this system.     

A cation exchange resin based on the condensation product of poly(iso-butyl vinyl ether) and furfural

A cation exchange resin was synthesized from the condensation product of poly(iso-butyl vinyl ether) and furfural by treating it with concentration sulphuric acid. The resin produced was characterized by measuring its total and salt splitting capacities, and by studying its thermal characteristics and behaviour to pH metric titration. The latter suggests the resin to be a weak one possibly containing ? COOH groups, which result from the oxidation of the furfural aldehyde group by sulphuric acid.     

Processable dodecylbenzene sulfonic acid (DBSA) doped poly(N-vinyl carbazole)-poly(pyrrole) for optoelectronic applications

A soluble poly (n-vinyl carbazole)–polypyrrole (PNVC–Ppy) copolymer was prepared through oxidative chemical polymerization wherein dodecyl benzene sulfonic acid (DBSA) was used as a dopant to facilitate polymer-organic solvent interaction and ammonium persulfate (APS) was used as an oxidant. Compared with undoped PNVC–Ppy, the DBSA-doped PNVC–Ppy copolymer showed higher solubility in some selected organic solvents. The composition and structural characteristics of the DBSA-doped PNVC–Ppy were determined by Fourier transform infrared, ultraviolet–visible, and X-ray diffraction spectroscopic methods. Field emission scanning electron microscopic method was employed to observe the morphology of the DBSA-doped PNVC–Ppy copolymer. The electrical conductivity of the DBSA-doped PNVC–Ppy copolymer was measured at room temperature. The conductivity increased with increasing concentration of APS oxidant, and the highest conductivity was recorded at 0.004 mol/dm³ APS at a polymerization temperature of ?5 °C. The increased conductivity can be explained by the extended half-life of pyrrole free radical at a lower temperature and a gradual increase in chain length over a prolonged time due to the slow addition of APS. Furthermore, the obtained soluble copolymer exhibits unique optical and thermal properties different from those of PNVC and Ppy.     

Synthesis and some properties of carbazole modified polyvinylchloride and the cation exchange resin therefrom

The chlorine displacement reaction between PVC and N-methylcarbazole-3,6-diamine affords a condensate which is insoluble in all possible solvents of PVC. The overall thermal stability of this condensate is appreciably higher than that of PVC. The dielectric behavior is also significantly different from that of unmodified PVC. Sulfonation of the PVC-carbazole condensate affords a cation-exchange resin with ? SO₃H and ? COOH functional moieties.     

Phthalic anhydride-based cation exchange resin from N-vinylcarbazole

A condensation product based on phthalic anhydride and N-vinylcarbazole has been prepared and processed into a sulfonic acid cation exchange resin. The resin produced has been characterized by measuring its total and salt splitting capacities and by studying its thermal characteristics, rate of exchange, and behavior to pH metric titration.     

A fibrous sulfonated cation exchange resin for purifying waste-water from electroplating from chromium (III) ions

Conclusions -- A method has been developed for preparing a fibrous sulfonated cation exchange resin based on partially hydrolyzed polyacrylonitrile fibres by the method of graft copolymerization with styrene sulfonates of the alkaline metals.-- An estimate of the functional groups in the sulfonated cation exchange resin has been made by the method of potentiometric titration. Apparent ionization constants have been calculated.-- The sorptive activity of cation exchange fibres with respect to trivalent chromium ions has been investigated on model solutions which imitate manufacturing process solutions. The sorptive capacity of the PAN-T_grPSSNA cation exchange resin with respect to the Cr³⁺ cation proved to be equal to 2.0 mmole/g.The process of regenerating the ion exchange resin has been studied. The degree of desorption of chromium is 96%.Translated from Khimicheskie Volokna, No. 3, pp. 51–53, May–June, 1990.     

Crystal growth inhibition of tetrahydrofuran hydrate with poly(N-vinyl piperidone) and other poly(N-vinyl lactam) homopolymers

Poly(N-vinyl pyrrolidone) (PVP) containing the 5-ring lactam and poly(N-vinyl caprolactam) (PVCap) containing the 7-ring lactam are well-known kinetic hydrate inhibitors (KHIs). For the first time we have synthesised and studied the performance of poly(N-vinyl piperidone) (PVPip), containing the 6-ring lactam, as a kinetic hydrate inhibitor. In the first part of the study we have investigated the ability of PVPip to inhibit the growth of tetrahydrofuran SII hydrate crystals. The results are compared to those of PVP and PVCap. Various polymer molecular weights have been investigated at varying subcoolings. PVPip shows an intermediate growth inhibition performance compared to PVP and PVCap at similar polymer molecular weights. In addition, the weight percentage concentration of polymer needed to achieve complete THF hydrate crystal growth inhibition increases as the polymer molecular weight decreases.     

Conformational characteristics of poly(N-vinyl pyrrolidone)

Conformational energies are calculated for poly(N-vinyl pyrrolidone) (PVP) chains as a function of stereosequence using semiempirical potential functions appropriate to peptides and n-alkanes. The planar pyrrolidone side groups are permitted to adopt both conformations which result in an eclipsed arrangement of the pyrrolidone NCH₂ or N(CO) and the C^aH^a bonds. Solvent interactions were considered in the manner used to treat other vinyl polymers bearing planar side groups. Dimensions and dipole moments were calculated using the RIS model developed for PVP from the conformational energies considering both the effects of stereosequence and temperature. Dipole moments were measured for three PVP samples with molecular weight ranging from 10 000 to 360 000. The dimensions and dipole moments calculated for atactic PVP chains agree with the dimensions reported in the literature and the dipole moments measured here.     

Modification of cation exchange membrane by grafted poly(4-vinyl-N-methylpyridinium-iodide)

It is well known that cation exchange membranes, having a very thin layer of a cationic polyelectrolyte on the membrane surface, have preferential permselectivity for monovalent cations in a monovelent-divalent cations system. We studied the relationship between preferential permselectivity and molecular structure of the cationic polyelectrolyte. Grafted poly(4-vinyl-N-methylpyridinium-iodide) was used and was compared with poly(4-vinyl-N-methylpyridiniumiodide). The backbone polymers were poly(styrene-co-p-benzylstyrene) and poly(benzyl), onto which 4-vinylpyridine was grafted by anionic polymerization and then quaternized with CH₃I. The grafted poly(4-vinyl-N-methylpyridinium-iodide) is effective in making the cation exchange membrane preferentially permselevtive for Na⁺ - Ca²⁺ system and is more preferable than poly(4-vinyl-N-methylpyridinium-iodide) in terms of electric resistance of the membrane. However, the relationship between the molecular structure of the cationic polyelectrolyte and the durability of the preferential permselectivity is not clear.     

硫酸再生阳离子交换树脂的实践

比较硫酸再生阳离子交换树脂与盐酸再生在酸消耗量、废水排放量及生产成本方面的差异,介绍再生过程的控制要点。通过比较可知,使用硫酸再生成本较低,酸源易得,并且解决了废水中氯离子处理难的问题, 实现了废水的环保排放。     

阳离子交换树脂催化合成富马酸二丁酯

以阳离子交换树脂（NKC-9）为催化剂、富马酸单甲酯和正丁醇为原料合成富马酸二丁酯,考察了原料配比、催化剂用量、反应时间和甲苯用量等因素对反应的影响以及催化剂的重复使用性能。最佳反应工艺条件为：n（正丁醇）∶n（富马酸单甲酯）=3.0∶1、w（NKC-9）=6.0%、反应温度不高于120℃、w（甲苯）=49.5%、反应时间2.5 h。结果表明,在该条件下富马酸单甲酯的转化率为98.1%;催化剂经重复使用6次后,富马酸单甲酯的转化率为96.9%。阳离子交换树脂（NKC-9）具有催化活性高、稳定性好、无环境污染等优点。     

Removal of zinc ions from aqueous solution using a cation exchange resin

The present study is concerned with the mass transfer and kinetics study of zinc ions removal from aqueous solution using a cation exchange resin packed in a rotating cylindrical basket reactor. The effect of various experimental parameters on the rate of zinc ion removal, such as initial zinc ion concentration, packed bed rotation speed and temperature has been investigated. In addition to find a suitable equilibrium isotherm and kinetic model for the zinc ion removal in a batch reactor. The experimental isotherm data were analyzed using the Langmuir, Freundlich and D–R equations. The equilibrium data fit well in the Langmuir isotherm. The experimental data were analyzed using four sorption kinetic models, pseudo-first and second-order equations, the Elovich and the intraparticle diffusion model equation, to determine the best fit equation for the biosorption of zinc ions onto purolite C-100 MH resin. Results show that the Elovich equation provides the best correlation for the biosorption process.     

Darzen's glycidic ester condensation reaction on poly(N-vinyl pyrrolidone)

About 38% conversion of carbonyl groups into epoxy functions in the molecular chain of poly(N-vinyl pyrrolidone) using chloracetamide results in the decreased viscosity of the product. De-epoxidation of the epoxy groups introduced shows the most contributing factor towards decreased viscosity is epoxy function.     

A novel conversion of sesamolin to sesaminol by acidic cation exchange resin

Sesame (Sesamum indicum L.) seed and its oil contain abundant lignans, including sesamin, sesamolin, sesamol, sesaminol, and their glycosides. In the present study, a novel reaction pathway, using an anhydrous solvent system, cation exchange resin catalyst, and HPLC for detection, was employed for the conversion of sesamolin into sesaminol. Under optimal conditions of 5 mL toluene, 90°C, initial sesamolin concentration of 6 mM, and catalyst dosage of 16.66 g/mmol of sesamolin, a 75.0% yield of sesaminol was achieved. The reaction mechanism was inferred to be that of a Friedel–Crafts reaction, with the catalyst showing remarkable catalytic activity and producing only slightly decreased yield after reuse in five subsequent batches. Owing to excellent reusability, low cost, and ready availability, this catalyst provides a very satisfactory option for converting sesamolin to sesaminol. Practical applications: Sesaminol is a potential natural antioxidant for use as a food additive and in medicinal applications, but it is a naturally occurring trace compound, and could be transformed from sesamolin under proper, specific conditions. The cation exchange resin 732 provides a satisfactory option for catalyzing the conversion of sesamolin into sesaminol. This suggests encouraging prospects for practical or industrial applications utilizing its notable catalytic performance, reusability, low cost, and easy availability.     

阳离子交换树脂分离纯化石杉碱甲的工艺研究

研究了5种离子交换树脂对石杉碱甲的吸附量和解吸率。结果表明,C004阳离子交换树脂的效果最好,其最佳工艺参数为:上柱液pH=3.0,上柱流速为3 BV/h,洗脱剂用3 mol/L氨水-70%乙醇,洗脱剂体积3 BV,洗脱速率1 BV/h。在此优化条件下,产品中的石杉碱甲含量可达5%。     

球形木素基正离子交换树脂的制备与性能

以木素磺酸钙为原料,在一种价廉无毒的分散介质中通过反相悬浮聚合制备了球形木素基正离子交换树脂。研究了分散介质和分散剂用量、聚合温度及搅拌速度等多种因素对聚合反应和成球效果的影响,并对交换树脂的形貌、粒径、含水量、密度、交换容量及吸附性能进行表征与测;定。结果表明,在实验室条件下,交换树脂对;Cr^3＋的饱和吸附量达到59．28mg／g（干树脂）。     

阳离子交换树脂催化的全乙酰基糖的合成

以CAT600阳离子交换树脂作为催化剂,醋酸酐既做溶剂又做乙酰化试剂,高效地进行了全乙酰基糖的合成。实验结果表明,所考察葡萄糖等8个糖类化合物在0.5 h内均能以较高的收率得到全乙酰基化的产物,产率达75%～95%。该方法具有高效、绿色、廉价、易于后处理等优点,有工业利用价值。     

阳离子交换树脂催化合成乙酸大茴香酯的研究

在强酸性阳离子交换树脂存在下,以大茴香醇和乙酸为原料合成乙酸大茴香酯.考察了反应时间、原料配比和催化剂用量等因素对合成反应的影响,确定了较佳的工艺条件:n(大茴香醇)∶n(乙酸)=1.0∶3.0,大茴香醇为1.0 mol,带水剂甲苯为180 mL,强酸性阳离子交换树脂用量为16.0 g,101℃～105℃回流反应12 h.乙酸大茴香酯的平均收率可达到92.5%,产品纯度达99.3%.