Fumi Masuko

Durable flame-retardant finished cotton fabrics characterized by thermal degradation behaviors

After a series of investigations on the durable flame-retardant finishes, it was thought to be important to study these durable flame-retardant finished materials from the thermal analytical standpoint. Accordingly, cotton fabric was finished with N-methylol dialkyl phosphonopropionamide (Pyrovatex C) by thermofixation and tetrakis (hydroxymethyl) phosphonium sulfate (THPS) precondensate by ammonia cure (Proban), as well as with THPS monomer by heat cure under various conditions, and subjected to the thermogravimetry (TG) to observe thermal degradation behaviors and obtain apparent activation energy (Ea). TG curves of Proban-finished samples showed the largest shift to lower temperatures with a steep slope; thermofixed THPS-finished sample gave a smaller shift with similar steep slope, whereas Pyrovatex-finished samples exhibited a similar shift but with a gradual slope. Ea versus residual ratio curves led us to conclude that CN bond-rich Proban polymer requires the highest Ea and decomposes with considerable rapidity, whereas ethylene-bond-rich Pyrovatex-finished samples with melamine crosslinking decompose gradually with the lowest Ea. As for the relationship between flame retardance and Ea distribution in the process of thermal degradation, typical differences among the above three kinds of finished samples were found, which are compared and discussed.

Pyrolytic Gas Generation of Cotton Cellulose With and Without Flame Retardants at Different Stages of Thermal Degradation: Effects of Nitrogen, Phosphorus, and Halogens

This study analyzes pyrolytic gases generated at various temperature ranges to observe changes in gas generation behavior dynamically in the process of thermal degradation. Cotton cellulose, a most flammable sample, is treated with compounds containing nitrogen and/or phosphorus as well as halogens with and without nitrogen. Each sample is heated thermogravimetrically, and pyrolytic gases are collected at various selected temperatures on the thermogravimetric curve for gas chromatographic and mass-spectrometric deter minations. The results reveal that flame retardant samples show extremely reduced amounts and fewer numbers of gas products compared with flammable samples, and some gases from flame retardant samples decrease with rising temperature, even disappearing at 500°C in the case of the (NH4)2HPO4-treated sample when flammable samples show further increases. Moreover, there is a considerable amount of toxic acrolein in flammable samples, but it is not detected or the amounts are much smaller in flame retardant samples. Acetonitrile, an effective radical scavenger, is found only in samples exposed to the synergistic effects of nitrogen and phosphorus or bromine. The results confirm that flame retardation works not only to inhibit combustion and subsequent gas generation, but also to scavenge pyrolytic gases already formed, resulting in a reduction or quenching of hazardous gas generation.

Chlorinating Silk with Methanesulfonyl Chloride in Dimethylformamide and Treating Chlorinated Silk with Mercaptans

Silk fibers were chlorinated with methanesulfonyl chloride in dimethylformamide under mild conditions. The chlorination occurred mainly at serine residues, and β-chloroalanine was found in the hydrolyzates of the chlorinated silk samples using gas chromatography-mass spectrometry, and was quantified using high performance liquid chromatography. About 30% of serine residues could be converted into β-chloroalanine residues. Chlorinated silk fibers reacted under alkaline conditions with mercaptans containing other functional groups, that is, thioglycollic acid, 3-mercaptopropionic acid, β-mercaptoethylamine, and cysteine, which yielded S-carboxymethyl, S-2-carboxyethyl, S-2-aminoethyl, and S-2-amino-2-carboxyethylcysteine residues, respectively. The amino group contents of the samples treated with β-mercaptoethylamine were higher than ten times that of the original silk. The amino group-enriched silk fibers were treated with methyl gluconates, yielding silk fibers containing pendant oligosaccharide groups. No interaction was observed between these modified silk fibers and a lectin, concanavalin A.

Gas Chromatographic and Mass Spectrometric Study of the Bromination of Protein Fibers with N-Bromosuccinimide and Triphenylphosphine

Silk fibers were brominated with a 1:1 (mole/mole) mixture of N-bromosuccinimide (NBS) and triphenylphosphine (TPP) in dimethylformamide. β-Bromoalanine (Brala) residues formed by the bromination of serine residues with NBS/TPP were very un stable under acid hydrolysis conditions, and Brala was not detected in the hydrolyzate of the brominated silk by gas chromatography-mass spectrometry of amino acids as their butyl esters of N(Q)-triftuoroacetyl derivatives. The brominated silk fibers were treated with aqueous solutions of ammonia and methyl-, ethyl-, propyl-, and butyl amines. Chromatographic-spectrometric analysis of amino acids of the treated silk samples showed the formation of corresponding β-aminoalanine and β-alkylami noalanines formed by the reaction of Brala residues, by direct condensation, or through the formation of dehydroalanine residues as intermediates. The analysis also showed that monobromotyrosine was formed by the treatment with NBS/TPP. Bromination of tyrosine residues must proceed by electrophilic substitution, probably by the action of free NBS in the reaction mixture.

Gas chromatographic and mass spectrometric behaviour of O-alkylserines as their N-trifluoroacetyl butyl esters

Abstract Four O-alkylserines were prepared from the corresponding alkyl O-alkyl-α-dehydroserinates by hydrogenation, followed by hydrolysis. The gas chromatographic behaviour of N-trifluoroacetyl butyl ester (BTFA) and N-trifluoroacetyl alkyl ester (RTFA) derivatives of the alkylserines and RTFA derivatives of the alkyldehydroserines was studied on columns of OV-17 and Dexsil 300 GC in relation to the chemical structures of the amino acids. Alkyldehydroscrine derivatives were more polar and eluted more slowly than alkylserine derivatives, which eluted as fast as alkylglycine derivatives of the same molecular weight. The stability of O-propylserine under the conditions for acid hydrolysis of proteins was compared with that of O-propyltyrosine and S-propylcysteine: the stability increased in the order O-propyltyrosine

Effect of Various Factors on Orange II Decoloration Reaction by Horseradish Peroxidase in the Presence of Detergent Enzymes

The effects of four detergent enzymes on the Orange II decoloration reaction by horseradish peroxidase (HRP) were investigated. Stainzyme, Lipex, Celluclean, and Savinase did not affect the decoloration reaction up to a concentration of 0.1% Under weak alkaline to alkaline conditions, the presence of four enzymes did not affect the decoloration reaction, but affected the decoloration reaction under neutral to acidic conditions. The effect of Ca2+ and Mg2+ concentrations on Orange II decoloration reactions in the presence of four enzymes was also investigated. Ca2+ and Mg2+ did not affect the decoloration reaction up to 500 ppm.

Correlation between Removals of Resins and Soils Observed in Soiled Resin Finished Fabrics during Cleansing Process

It seems probable that the removal of soils from resin finished fabrics occurs simultaneously with the removal of resins during the cleansing process, but the observation for the removal of resin has been ignored so far. Therefore, a simultaneous observation for the removal of resin and soils was carried out in this study to investigate the effect of resin finish on the detergency of soils together with that of stains on the removal of resins. The results disclosed a correlation between the above two effects as follows: 1) Water soluble soils became more removable by resin finish with an increase in the removal of resins from resin finished fabrics. 2) The detergency of oily soils was reduced by resin finish and only a little removal of resin was observed with oily soils on resin finished fabrics. 3) A mixture of hydrophilic and hydrophobic soil as Chinese ink on resin finished fabrics gave a little removal of resins and its detergency was slightly influenced by resin finish. 4) Also dry cleaning showed a tendency that any increase in the removal of resins gave an improved detergency and reduction in detergency showed little removal of resins.