G. Bruce Guise

Gel permeation chromatography of a polyamide—epichlorohydrin resin and some other cationic polymers

Abstract The gel permeation chromatography of cationic polymers, a polyamide—epichlorohydrin resin (Hercosett 125), poly(2-vinylpyridine) and polyethyleneimine, was compared on a selection of silica gel columns with neutral and cationic surface modifications. The elution volumes of the polymer peaks were very dependent on the pH, ionic strength and the column, but were also influenced by the type of salts in the eluent and the polymer concentration. In some cases it was possible to elute the cationic polymer anywhere between the high-molecular-weight exclusion limit and the low-molecular-weight total permeation limit. The polymer peak in Hercosett 125 split into two under certain conditions. This appears to be related to the presence in Hercosett 125 of polymers of different structures. Universal calibration methods and viscosity measurements have been used to indicate conditions where interaction between the cationic polymers and the columns and/or solvent was minimal and these conditions have been used to estimate the molecular weight of Hercosett 125.

Treatment of Wool Fabrics with Mixtures of Fluorochemicals and Shrink-Resist Polymers

The influence of polymeric shrink-resist finishes on the durability on wool of fluorochemical stain and soil repellents was examined. In some cases the durability to washing, drycleaning, and abrasion of the fluorochemical (as judged by oil and water-repellency tests) was improved. The best results were obtained by addition of FC-234 (3M Company) to Sirolan BAP pad treatments. This combination also showed improved durability on cotton and polyacrylonitrile when cured with organo metallic catalysts.

Chromatography of polycarbamoyl sulphonates (anionic polyurethane derivatives)

Abstract The composition of some polyurethanes used to shrink-resist wool with a poly(propylene oxide) backbone and terminal −NHCOSO 3 − Na + groups, i.e. polycarbamoyl sulphonates (PCSs), have been investigated by chromatographic methods. The molecular weight distribution at different stages in the preparation of PCSs was examined by gel permeation chromatography (GPC) using detection methods appropriate to either the total polymer concentration or the number of terminal groups. Low-molecular-weight impurities in PCS preparations were investigated by GPC and reversed-phase liquid chromatography. Problems in assigning PCS molecular weights on aqueous GPC on a surface modified silica column were resolved by the use of polystyrene gel columns and tetrahydrofuran eluent with either: (i) the conversion of the PCS to a urea derivative by reaction with di- n -butylamine, or (ii) changing the PCS counter ion from sodium to methyltrioctylammonium. The principle of the second method was also applied to some cationic polyurethane derivatives. Reaction with 1-(2-pyridyl)piperazine converts carbamoyl sulphonates and isocyanates into derivatives with strong ultraviolet absorption at 300 nm. This derivatization reaction gives an estimate of the number of terminal carbamoyl sulphonate groups in the GPC fractions of a PCS, or terminal isocyanates in polyisocyanates. This method was the most sensitive way to estimate the bisulphite adduct of hexamethylene diisocyanate in PCS preparations.

Shrink-Resisting Wool with Poly(Dimethylsiloxane)-α,ω-Diols and Aminofunctional Silane Crosslinking Agents Part II : Influence of Crosslinking Agent Struc ture

An investigation (previous paper) of shrink-resisting wool from perchloroethylene solvent treatments with poly(di methylsiloxane)-α,ω-diols and aminofunctional silane crosslinking agents was continued. A poly(dimethylsiloxane)- a,w-diol of molecular weight 55,000 was crosslinked with polyalkoxysilanes with side-chains containing various functional groups. Effective shrink resistance was only obtained with silanes containing at least two amino groups. Analogues of 3(2-aminoethylamino)-propyltrimethoxysilane with different alkoxy or amino functional groups were synthesized, and both these structural changes were found to influence significantly the development and effectiveness of the shrink resistance.

Shrink-Resisting Wool with Poly(Dimethylsilozane)-α,ω-Diols and Aminofunctional Silane Crosslinking Agents Part I : Influence of Silicone Molecular Weight

This and the following paper study shrink-resist finishes for wool using poly(dimethyliloxane)-α ω-diols (I) and poly functional silane crosslinking agents. In this paper treatment of wool fabric from organic solvents with the diols (I) of various molecular weights and a single silane, 3(2-aminoethylamino)propyltrimethoxysilane, (II) was examined in detail. Important factors for effective shrink resistance were the molecular weight of the diol (I), the concentration of amino functional silane (II), the extent of reaction before and after application to wool, the reaction with water, and the presence of an organotin catalyst or polyalkoxysilanes such as methyltrimethoxysilane. These findings were used to modify a commercial silicone shrink-resist finish for use in a durable press treatment.

Comparison of Some Soft Unplasticized Cast Polyurethane Rubbers

Abstract Different types of unplasticized cast polyurethanes with hardness around 60 Shore A have been compared. The tensile properties, tear strength, resistance to hydrolysis, and swelling in solvents and water were examined. The influence of composition on the properties of cast polyurethanes prepared from a polyadipate polyol and diisocyanates, including the effect of a range of fillers, was investigated in detail. Fumed silica, fumed alumina, and carbon black significantly increased the hardness and tensile strength of the rubber, whereas kaolin and talc gave small increases. Ground silica, calcite, and rutile had no effect. No significant increases in tensile strength were obtained with silane and titanate coupling agents with a fumed silica filler. The rate of hydrolysis or extent of swelling in xylene was unchanged by fillers.

Polybutadiene Shrink-Resist and Durable-Press Finishes for Wool

Liquid low-molecular-weight polybutadienes have been investigated as potential shrink-resist finishes for wool. These polymers could be crosslinked thermally, but a better method used reactions of functional end-groups such as amino, carboxyl, or hydroxyl. For example, polybutadienes with hydroxyl or carboxyl groups could be crosslinked on wool with polyisocyanates, and aminopoly-butadienes with polyepoxides. Many of these polybutadiene finishes imparted a high level of shrink resistance to an untreated worsted wool fabric, and the properties of fabrics treated by some of these have been compared. Durable-press finishes were produced with polybutadienes, including a delayed-cure treatment.

Single Thread Shrinkage of Polymer Treated Wool Fabrics

Single thread shrinkage in two light-weight, plain weave wool worsted fabrics has been studied with a range of shrink-resist polymer treatments that depend on an interfiber-bonding mechanism, with different finishing treatments before polymer ap plication, and with a selection of wash tests. Single thread shrinkage generally developed from thicker than normal yams, but not all thick yams developed single thread shrink age. A staining test showed that polymer was lost more readily during washing from the thicker yam sections. It was difficult to study single thread shrinkage quantitatively, and it was necessary to make comparisons at the same level of area shrinkage, since the number of single thread shrinkage spots increased as washing progressed. The number of spots per unit area in samples washed to 10% area shrinkage varied with the polymer applied, and for one polymer treatment, the spots decreased with increasing polymer concentration. The number of single thread shrinkage spots on warp and weft yarns was different. One recommendation examined to alleviate single thread shrinkage was to pressure decatize fabrics before polymer application. Such fabrics showed improved shrink resistance with Synthappret BAP but not with other polymers. The pressure decatization did not remove single thread shrinkage; instead it was nec essary to wash treated samples for a much longer period before it became apparent.