István Rusznák

Enzymes and chelating agent in cotton pretreatment.

Desized cotton fabric and cotton seed-coat fragments (impurities) have been treated with commercial cellulase (Celluclast 1.5 L), hemicellulase-pectinase (Viscozyme 120 L) and xylanase (Pulpzyme HC) enzymes. Seed-coat fragments hydrolyzed much faster than the cotton fabric itself. This relative difference in hydrolysis rates makes possible a direct enzymatic removal of seed-coat fragments from desized cotton fabric. Addition of chelating agents such as ethylenediamine-tetra-acetic acid (EDTA) markedly enhanced the directed enzyme action. Pretreatments carried out in acidic solution at pH 5 increased the lightness of seed-coat fragments, contrary to the samples treated in neutral medium at pH 7. Alkaline scouring resulted in darker seed-coat fragments except for the samples pretreated with Pulpzyme HC plus EDTA. This effect is similar to that observed in the biobleaching process in pulp and paper industry.

A study of epoxy resin–acrylated polyurethane semi‐interpenetrating polymer networks

Epoxy resin–acrylated polyurethane semi-interpenetrating polymer networks (semi-IPNs) were synthesized containing various ratios of the diglycidyl ether of bisphenol-A (DGEBA)-based epoxy resin and an acrylated aliphatic urethane oligomer. The synthesis was carried out in the presence of a mixture of triarylsulfonium hexafluoroantimonate salts as a dual photoinitiator that initiates both the cationic polymerization of the epoxy resin and the free-radical polymerization of the acrylated urethane oligomer simultaneously, upon irradiation with ultraviolet light. The simultaneous photopolymerization, followed by isothermal differential scanning calorimetry measurements, gave rise to simultaneous semi-interpenetrating polymer networks (semi-SINs). During polymerization, partial inhibition of the cationic polymerization was noticed. This was investigated by determination of the gel content and the infrared spectroscopy of the soluble fraction, after extraction of the synthesized polymer films in a Soxhlet apparatus, and by determination of the network density of investigated systems with thermal mechanical analysis. The compatibility of the components in the semi-IPNs was investigated by dynamic mechanical thermal analysis. It was found that glass transition temperatures are shifted inwardly, which indicated that the epoxy resin–acrylated polyurethane semi-IPNs were compatible.

Combining Traditional Cotton Scouring with Cellulase Enzymatic Treatment

The action of a cellulase enzymatic pretreatment in the efficient alkaline scouring of cotton fabrics is studied and reported in this work. Improved removal of seed-coat fragments is the primary goal of the experiments, and spinning blowroom waste, rich in seed-coat fragments, is the main target substrate for enzymatic studies. Commercially available cellulase enzyme, a complex mixture of cellulase components (endo- and exoglucanases, beta-glucosidase) and accompanying enzymes (e.g., hemicellulases. pectinases ), is used throughout the experiments. Depending on time and enzyme con centration, 28-34% of the spinning blowroom waste can be hydrolyzed by cellulase. With consecutive cellulase treatment and traditional pad-steam scouring, weight loss is as high as 78-86%. Alkaline cotton scouring (control) results in only 66% weight loss. The cellulase enzyme complex makes the residual seed-coat fragments more ac cessible to scouring chemicals. The effect of enzymatic treatment on seed-coat fragment removal from desized cotton fabric is also significant. As photomicrographs show, the tiny fibers that attach the seed-coat fragments to the fabric are hydrolyzed by the enzyme, facilitating removal of these impurities from the fabric surface.

Role of interfacial layers in the properties of particle-filled polyolefin systems

Abstract Modified interfacial layers were studied in polypropylene—calcium carbonate systems compounded in a single-step process with a surface-active agent and an elastomer simultaneously. Samples with etched and non-etched surfaces were investigated by dielectric spectroscopy and scanning electron microscopy. An increase in the thickness of the interfacial layer was brought about by the increasing elastomer content of the system. However, when the concentration of the latter exceeded a critical upper limit, a new disperse elastomer phase could be observed in the matrix. The value of the critical concentration depends upon the type of elastomer and it is a characteristic parameter for a given polymer—elastomer system. Deformations and failure in the composite system are determined by the interfacial layer. A thick elastomer interphase around the filler particles acts as a bumper layer and stops the crazes. The interactions between the components and the change in the mechanical properties induced by the presence of named additives were also investigated by mechanical spectroscopy.

Elastomer interphase in particle filled polypropylene; structure, formation and mechanical characteristics

34 Introduction 34 Materials and Methods 35 Sample Preparation 37 Results and Discussion 37 References 59 Paper submitted for publication August 1991

Determination of molar mass distribution of alkyl polyethylene glycol ethers

A process based on gas chromatographic separation and on the computerized evaluation of the results has been developed for the determination of the distribution and distribution coefficients of alkyl polyglycol ethers, formed in the competitive, consecutive reaction of fatty alcohol and ethylene oxide. A comparison of experimental and theoretical distributions showed that the distribution is the Weibull-Nycander-Gold type for potassium hydroxide catalyst, and the Flory type in the antimony pentachloride catalyst. The characteristic of the distribution does not change with reaction parameters in either type of distribution, though actual distribution is slightly modified by temperature. In determinations of Weibull-Nycander-Golds c and Natta-Manticas ci-s distribution coefficients, the Weibull-Törnquist effect, i.e., the changing of the distribution coefficients with ethoxylation, has been experimentally proven in the example of ethoxylation catalyzed with potassium hydroxide.

A novel way for ethoxylation with basic catalysts

Ethoxylation of dodecyl alcohol catalyzed by alkali hydroxides are accelerated by adding complexing agents for the alkali ions. The rate of ethoxylation could be increased by crown ether and dodecyl alcohols of a higher degree of ethoxylation. The effect is more pronounced with the crown ether; thus, reactions not taking place under other circumstances could also be carried out. The complexing additives have no significant effect on the molar mass distribution, The reaction could also be accelerated by using more bulky organic cations (e.g., triethylbenzylammonium ion) instead of the alkali cation.

Nuclear magnetic resonance investigations of the Azo-Hydrazone tautomerism of azoreactive dye chromophores

High‐field 1H and 13C NMR methods (e.g. 1H{1H} and 13C{1H} NOE spectroscopy) were used to examine the tautomeric characteristics, particularly with regard to the question of azo–hydrazone tautomerism, of two azo dyes. Full 1H and 13C NMR signal assignments are given for both molecules. The NMR results indicate that in DMSO solution the tautomeric equilibria are shifted predominantly toward the hydrazone from II in both compounds. The presence of a fast II=III interconversion could also be plausibly assumed.

Nitrogen containing compounds

Bridge-head nitrogen-containing compounds, (1,4-diaza-bicyclo-[2.2.2]-octane, 1-azabicyclo-[2.2.2]-octane, 1,5-diaza-bicyclo-[5.4.0]-undec-5-ene and l-azabicyclo-[2.2.2]-octane-3-one), successfully catalyze the ethoxylation of dodecyl alcohol. The catalytic activity of any of the first two compounds was four to five times higher than that of an open-chain, symmetrical trialkylamine of similar basicity. The molar mass distribution of the ethoxylated dodecyl alcohol derivatives was of the Weibull-Nycander-Gold type. No Weibull-Törnquist effect could be detected, however, unlike the case realized in ethoxylated systems gained in the presence of trialkylamines. No change in the distribution constant (calculated according to Natta and Mantica) could be observed in the course of these ethoxylation reactions.

Removal of dyes from industrial wastewater by cucurbiturils

Homolog mixture of basic molecules of cucurbiturils has been synthesized and cucurbit[6]uril (CU[6]) and cucurbit[8]uril (CU[8]) have been isolated by means of solvent extraction. Inclusion complexes of different acid, reactive and disperse dyes have been produced by them. CU[8] was decidedly more efficient in complex formation with all the studied dyes than CU[6]. Competitive complex formation between randomly methylated ß-cyclodextrin and the respective cucurbiturils with disperse dyes has been studied and superiority of CU[8] could be demonstrated. The complex forming efficiency of the cucurbiturils with acid and reactive dyes was markedly increased in the presence of Ca, Mg, K and Na ions, respectively, in water solution.