Studies of porous polymer gels. I. One-step suspension technique for preparation of moderately crosslinked methacrylic acid gels

A new method of preparation of carboxyl cation exchangers directly from methacrylic acid and divinylbenzene is described. A suspension technique with a concentrated aqueous calcium chloride solution as the water phase was used. n-Octane and toluene were inert diluents of the monomers. The copolymers obtained have high ion-exchange capacity (9.6–10.6 mequ./g) and porous structure.     

Electrosynthesis in systems of two immiscible liquids and a phase transfer catalyst. V. The anodic chlorination of naphthalene

The anodic chlorination of naphthalene in a water/methylene chloride emulsion and using tetrabutylammonium ion as the phase transfer catalyst is demonstrated; in conditions where the aqueous phase is saturated NaCl, the organic yield of 1-chloronaphthalene is 56% and the current yield is 33% after the passage of 2.33 F mol^–1 of naphthalene. It is shown, however, that when the aqueous phase also contains zinc chloride so that the species transferred is [(C₄H₉)₄N⁺]₂ZnCl ₄ ^–– , the yields can be increased to 92% and 49% respectively. The mechanism of these chlorinations is discussed.     

Methyl Oct-cis-2-enoate. its synthesis,GLC behaviour and infrared spectra

Methyl oct-cis-2-enoate was synthesized by selective hydrogenation of methyl oct-2-ynoate at atmospheric pressure with quinoline poisoned palladium as catalyst. The resulting product contained only 7% of thetrans form, as determined by GLC. The structure was confirmed by infrared spectra. Analysis of the infrared spectra is given. The cis andtrans forms of methyl oct-2-enoate were separable by GLC in polar or non-polar columns. GLC runs in polar and non-polar phases showed that the α position of the double bond of methyl oct-2-enoate so affects its properties, that practically no interaction was observed between the double bond and the polar phase. Consequently volatility was the main factor determining the retention times of cis andtrans methyl oct-2-enoate in the polar and non-polar phases studied.     

Influences of zinc oxide and an organic additive on the electrochemical behavior of pure aluminum in an alkaline solution

The corrosion behavior of pure aluminum in inhibited and uninhibited 4 MKOH was investigated by means of hydrogen collection, polarization curve measurement and electrochemical impedance spectroscopy (EIS). The results showed that the corrosion of pure aluminum was greatly inhibited by the addition of ZnO and dimethyl amine epoxy propane (designated as DE). EIS and EDAX analyses revealed that ZnO produces its effect by depositing on the aluminum surface, which increases the overpotential of hydrogen evolution. It was also found that the addition of DE could greatly improve the deposition of zinc layers.     

Composites based on eucalyptus tar pitch/castor oil polyurethane and short sisal fibers

Polymeric materials are being developed with renewable resources to promote industrial progress with environmentally friendly technologies. For this reason, polyurethane samples were prepared with 4,4′‐diphenylmethane diisocyanate (NCO/OH = 1), eucalyptus tar pitch (biopitch), castor oil as a polyol, and dibutyltin dilaurate as a catalyst. These materials were reinforced with different contents of short sisal fibers (0, 2.5, 5.0, 7.5, and 10.0%) and were prepared by resin‐transfer molding. The composites were characterized by IR absorption spectroscopy, thermal analysis (thermogravimetry and differential scanning calorimetry), impact resistance, scanning electron microscopy, and water absorption resistance. These materials showed hydrophobic characteristics, despite the addition of sisal fibers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3797–3802, 2003     

Structural and mechanical characteristics of aramid fibres for bullet-proof vests

The following conclusions can be drawn from an analysis of the data reported in the present article: SVM and Armos fibres are now the most promising for use in bulletproof materials; increasing the elongation to 5–6% while preserving the strength at the level of 400–450 kgf/mm ² allows increasing the efficiency of use of fibres for bulletproofing; the method proposed here allows rapidly and efficiently conducting comparative tests and initial selection of materials and the pack structure of the energy-absorbing polymer support; new types of bulletproof fabrics must be developed to increase the efficiency of manifestation of the energy-absorbing properties of fibres. Translated from Khimicheskie Volokna, No. 6, pp. 37–40, November–December, 1997.