Stanley P. Rowland

Removal of mercury from aqueous solutions by nitrogen-containing chemically modified cotton

The authors thank 0. Clifton Taylor, Raymond Tenorio, and Eugene A. Cardiff for the preparation and a generous supply of PAN. Note Added in Proof. Chemiluminescence generated by bubbling PAN through a solution of triethylamine in acetone (1% V/V) was approximately twice as intense as that produced in the vapor phase reaction. The results were more reproducible in the liquid phase than in the vapor phase. Therefore, the liquid phase chemiluminescence seems to be more suitable for atmospheric monitoring applications.

Introduction of Ester Cross Links into Cotton Cellulose by a Rapid Curing Process

The reaction of polycarboxylic acids with cotton at elevated temperature has been investigated as a function of partial neutralization of the carboxylic acid with sodium carbonate or triethylamine. A high level of cellulose cross-linking was realized with a variety of polycarboxylic acids having three or more carboxyl groups per molecule, although only partial esterihcation of the carboxyl groups occurs in this process. The use of polycarhoxylic acids in the form of their partial salts results in broader applicability of this rapid esterification process of cross-linking, in improved add-ons and performance characteristics of the modified cotton, and in reduced acid tendering of the treated fabrics.

Reagent Migration and the Performance of Durable-Press Fabrics

In order to delineate the effects on reagent migration on the textile-performance properties of durable-press fabrics, dimethyloldihydroxyethyleneurea (DMDHEU) and N-methylolpolyethyleneurea, degree of polymerization = 2, were applied to cotton printcloth under slow and rapid drying conditions, which effected uniform and nonuniform crosslink distributions through the fabric thickness. These reagents are representative of conventional and network polymer forming cross-linking reagents, respectively. The crosslink uniformity (or nonuniformity) was measured in the DMDHEU series with a negative Direct Red 81 staining technique. Fabrics with a uniform distribution of crosslinks throughout the fabric thickness were the point of reference. The concentration of crosslinks on fabric surfaces effected by reagent migration during rapid drying resulted in a) comparable development of resilience, b) slightly better retentions of breaking strength, tearing strength, and elongation, c) greater weight losses in Accelerotor abrasion, and d) comparable retention of Stoll-flex abrasion resistance. These trends occurred with both reagent systems and were detected at both the low and high levels of reagent incorporation. The results are discussed in relation to the distribution of crosslinks.

Effects of a Poly(Sodium Acrylate) Finish on Moisture-Related Properties of Cotton-Containing Durable-Press Fabrics

Durable-press cotton/polyester fabrics with 100%, 79%, 50%, 35%, and 0% cotton contents were modified by in situ network polymerization of sodium acrylate. The fabrics were characterized for mositure-related properties. There were substantial reductions in both drop absorption and wicking times at about 1% add-on of poly(acrylic acid) with little change in other properties. At about 4% add-on of poly(acrylic acid), substantial increases in moisture regain and water of imbibition accompanied shorter times for drop absorption and wicking up 2 cm and 3 cm of fabric. Other textile performance properties are discussed in relation to the hydrophilic characteristics of the fabrics.

Mobile Ester Cross Links for Thermal Creasing of Wrinkle-Resistant Cotton Fabrics

Ester cross linkages in cotton cellulose have been investigated for mobility (trans esterification) at elevated temperature. Cotton cellulose polycarboxylates were prepared by reaction of cotton print cloth with polycarboxylic acids having 3-6 carboxyl groups per molecule, at least two of the carboxyl groups being on adjacent carbon atoms. Durable creases were developed to various degrees when these fabrics were subjected to thermal creasing treatments subsequent to the cross-linking reaction. Thermal mobil ity of ester linkages in selected model compounds has been shown to result from participation of the unesterified carboxyl group adjacent to the ester linkage. The cyclic anhydride was detected from dissociation of model ester compounds at elevated tempera tures; similar cyclic anhydrides are the probable intermediates in transesterification of ester linkages in cotton cellulose polycarboxylates.

Some Interactions of Water-Soluble Solutes with Cellulose and Sephadex

Elution of a variety of types of water-soluble solutes from gel-permeation columns of chopped native cotton and of Sephadex G-15 was studied. Evidence was obtained concerning (a) the fraction of internal water that is available as solvent water for selected types of solutes, (b) the sorption of strong donor and acceptor hydrogen-bonding solutes on cellulose and Sephadex surfaces, and (c) negative sorption (or repulsion) of carboxyl-containing solutes.

Effect of base concentration upon the reactivities of the hydroxyl groups in methyl d-glucopyranosides

Abstract The anomeric methyl D -glucopyranosides were treated with N,N-diethylaziridinium chloride in various molarities of aqueous sodium hydroxide at variable ionic strength and constant ionic strength. It was found that the extent of reaction of the hydroxyl groups at C-2, C-3, and C-4 decreased with increasing concentration of base. Reaction at the C-6 hydroxyl group remained essentially constant with increasing concentration of base. Neither varying the ionic strength nor the concentration of reagent affected the distribution of substituents at any given concentration of base.

Selective Accessibilities of Hydroxyl Groups in the Microstructure of Cotton Cellulose1

The reactions of 2-chloroethyldiethylamine with the hydroxyl groups at C-2, C-3, and C-6 of the d-glucopyranosyl unit of cotton cellulose were investigated as a means of evaluating the relative accessibilities of these hydroxyl groups in heterogeneous reactions of fibrous cellulose. The relative rate constants for reactions of the individual types of hydroxyl groups were determined from reactions of cellulose in solution and from reactions of disordered cellulose in heterogeneous systems. Quantitative determinations of the distributions of 2-(diethylamino)ethyl substituents in the mono-substituted d-glucopyranosyl units involved hydrolysis of the chemically modified cellulose to glucose and substituted glucoses followed by gas-liquid chromatographic analysis. The relative accessibilities of the hydroxyl groups at C-2 and C-3 vs those at C-6 were estimated for crystalline celluloses by employing the relative rate constants (noted above) together with the experimentally measured distributions of substituents resulting from heterogeneous reactions of crystalline celluloses and appropriate kinetic expressions. The relative accessibilities of the hydroxyl groups at C-2, C-3, and C-6 in cellulose in strong mercerizing media approach those of cellulose in solution. In media of lower concentration of sodium hydroxide (i.e., 4 N or 13.9%), selective accessibilities of the individual types of hydroxyl groups become evident, and these selective accessibilities become pronounced in sodium hydroxide solutions of still lower concentrations (e.g., N and 2 N).

Effects of selected reaction conditions and structural variations on the distribution of 2-(diethylamino)ethyl groups on d-glucopyranosyl residues of 2-(diethylamino)-ethylated cellulose, starch, and the anomers of methyl 4,6-O-benzylidene-d-glucopyranoside

Abstract The reactivities of the hydroxyl groups in cellulose, starch, and the anomers of methyl 4,6- O -benzylidene- d -glucopyranoside with 2-(diethylamino)ethyl chloride have been investigated under identical conditions in ( a ) aqueous and ( b ) nonaqueous medium. For cotton cellulose, the relative distribution of 2-(diethylamino)ethyl groups on the 2-, 3-, and 6-hydroxyl groups in the mono- O -[2-(diethylamino)ethyl]- d -glucopyranose fraction of the hydrolyzate was found to be independent of the D.S. Cellulose treated with 2-(diethylamino)ethyl chloride in p -dioxane showed a higher ratio of substituents on the 2- and 3-hydroxyl groups, relative to the 6-hydroxyl group, than resulted when the reaction was conducted in an aqueous medium. Consideration of these results on the basis of the fraction of substituents in each of the three positions showed that the increase in substitution on the 2-hydroxyl group is accompanied by a decrease in substitution at the 6-hydroxyl group and little change in that at the 3-hydroxyl group. Starch follows a similar pattern, but the increase in substitution on the 2- and 3-hydroxyl groups, relative to the 6-hydroxyl group, is more pronounced than for cellulose under identical conditions. The fractions of substituents on the 2-hydroxyl groups increases as a result of reaction in p -dioxane. The increase in substitution at the 2-hydroxyl group is accompanied by a decrease in that at the 6-hydroxyl group, but here a substantial increase in substitution at the 3-hydroxyl group occurs. With regard to the change in fraction of substitution at the 3-hydroxyl group with change in the reaction medium, methyl 4,6- O -benzylidene-β- d -glucopyranoside behaves similarly to cellulose, and the α- d anomer behaves similarly to starch.

Gel Permeation Properties of Cellulose II: Comparison of Structures of Decrystallized Cotton Cross . Linked With Formaldehyde by Various Processes

Application of gel permeation chromatography, which has been shown to be an effective means of measuring changes produced in the accessibility of decrystallized cotton cellulose by one form of formaldehyde cross-linking [9, 10], has been extended to the study of alterations of the structure of decrystallized cotton produced by intro duction of formaldehyde cross links under various other reaction conditions. These include reaction in aqueous solution (Form W), in the vapor phase (Form V), in acetic acid solution (Form D), each with high and low concentrations of formaldehyde, and in a bake-cure process (Form C). The properties determined by gel permeation chroma tography are the effective internal solvent volume derived from measurements of selective permeability to solutes of decreasing molecular weight and the limit of per meability to solutes of increasing molecular size. Striking differences were revealed in both the nature and magnitude of the alterations of accessibility resulting from differ ent reaction conditions employed for formaldehyde cross-linking. Corresponding changes were observed in gross properties of the cellulose polymer gels, such as the extent of swelling measured by the volumes occupied by the swollen gels per gram of dry solids. Accessibility was increased by reactions in aqueous solution which produced cellulose having larger internal volumes and permeability limits than the unmodified, decrystallized , cellulose. The reaction catalyzed by hydrochloric acid in the acetic acid medium formed products having larger internal volumes, but somewhat lower limits of permeability. Both the internal volume and the permeability limit were decreased by the bake-cure process which produced a polymer having much lower accessibility than the unmodified, decrystallized cellulose.