Brenda J. Trask

Durable Flame-Retardant Treatments for Blends of Cotton, Wool, and Polyester:

Durable flame-retardant treatments based on a vinyl phosphonate oligomer or Thps were applied to cotton, cotton/polyester, cotton/wool, and cotton/polyester/wool medium-weight twill fabrics. The treatments were applied by either a pad, dry, cure process or a two-step procedure consisting of a pad, dry, cure application of DMDHEU followed by a Thps-NH3 cure process. Flammability of the treated fabrics was evaluated by a number of tests, including burning rate, vertical char length, oxygen index, and a flame-extinguishment test. Physical properties were determined by standard tests to measure breaking strength, wrinkle recovery, stiffness, durable- press rating and shrinkage due to laundering. Cotton/wool blend fabrics treated with Thps-urea-TM M had the best flame-retardant properties.

The Effects of Air Pollution on Exposed Cotton Fabrics

This report covers the results of one-year exposure studies of cotton fabrics exposed at different environmental sites in the metropolitan St. Louis, Mo., and Chicago, III. areas. The 12 sites range from heavy industrial to essentially rural. The data presented definitely establish a relationship between air pollution and accelerated degradation of cotton fabrics. The data include strength retention of several cotton fabrics and air pollution data, as determined by periodic measurement of dustfall, suspended particulate matter, sulfation, and sulfur dioxide.

A Microscopical Survey of Flame-Resistant Cotton Fabrics Part I: Treatments Based on THPOH-NH 3

Three cotton printcloth fabrics treated for flame resistance with THPOH-NHx, oxidized and nonoxidixed, were studied by light microscopy and by transmission (TEM) and scanning (SEM) electron microscopy. Chars of the treated fabrics were also examined. Staining with Acid Blue I and examination by light microscopy provided a semicluantitative assessment of penetration of nonoxidized THPOH-NHa into yarns and fibers, but was less effective with the oxidized sample. SEM observations indicated polymer build-up on fabric surfaces. Deposits of polymer between fibers were usually heavier around the periphery of the yarn. Laundering removed surface deposits but oxidized samples laundered 50 times were still flame resistant, TEM of ultrathin cross sections showed that no major structural change had occurred in the treated fibers. Both SEM and TEM of fiher char sections indicated that the fibers had become shells on burning. Residue patterns left by treated fiber sections after microincineration suggested that the laulymer had completely penetrated the fibers.

Effects of Heat on Cotton, Polyester, and Wool Fibers in Blended Fabrics - A Scanning Electron Microscopy Study

Treating cotton textile fabrics with phosphorus-containing flame retardant finishes reduces the flammability of the fabrics. The presence of fibers other than cotton in blended fabrics changes the burning rates and char lengths of the fabrics, as well as the nature of the resultant chars. To better understand the relationship of blended fibers during burning, and the response of each fiber to heat, scanning electron microscopy was used to study structures of blended cotton/polyester and cotton/ wool fabrics, and of individual fibers, both before and after exposure to flames. In blended fabrics, changes in physical structures of polyester and wool were observed before those in cotton. Chars of blended fabrics were more stable than those from either fiber alone, because the charred cotton formed a network onto which the melted polyester and wool could flow. These melts in turn protected and strengthened the cotton residue.

Wool -- Its Effect on Flame-Retardant Properties of Blend Fabrics

Durable phosphorus-based flame retardants were applied to twill fabrics con taining cotton and wool to study the effect of wool on the flame retardancy and physical properties of the blend fabrics. The presence of wool in untreated blend fabrics caused burning rates to decrease and oxygen index values to increase as wool content increased in the blends. These effects were also observed in cotton/ wool blends treated with low levels of the Thps-urea-TMM flame retardant, but were less pronounced in fabrics treated at high levels. Thermogravimetric analyses were conducted to study the thermal degradation of the treated and untreated fabrics. The presence of wool in treated blend fabrics did not sig nificantly change strength retention, area shrinkage and wrinkle recovery values in comparison to similarly treated 100% cotton fabrics.

Polyacrylates in flame retardant treatments of textile fabrics

Durable phosphorus-based flame retardants containing polyacrylate emul sions were applied to cotton, cotton-polyester, and cotton-wool twill fabrics to study the effect of the added polyacrylates on the physical properties and flame retardancy. The Thps-urea-TMM flame retardant with added polyacrylate im parted better overall physical properties to 100% cotton fabric than to cotton blend fabrics. Treatments containing polyacrylates with low glass transition temperatures produced fabrics with the highest abrasion resistance, tearing strength and wrinkle recovery. The flame retardancy of treated fabrics was not adversely affected by the addition of polyacrylates to the flame retardant treatments.

Technique for Measuring the Oxygen Index of Fibrous and Powdered Cellulose Derivatives

A technique to assess the flame resistance of small quantities of fibrous or powdered derivatives of cotton cellulose was developed. The procedure is an adaptation of the oxygen index (OI) fabric flammability test. Cellulose fibers or powders were pressed into 0.5-g discs, 1 1/4 in. in diameter which were used to measure the OIs in the instrument employed for fabric OI determinations. Comparison of OIs of discs and fabrics representing untreated and conven tionally treated FR cottons resulted in a linear relationship; disc OI values were higher due to higher fiber density and lower accessibility of oxygen to the substrate. Among the experimental treatments of cotton cellulose, OI values of fibrous and powdered celluloses were uniformly low with increasing tritylation, peaked and dropped with increasing tosyl concentration and rose with increas ing mesylation. Some derivatives would be considered flame resistant.

Measurement of the Ultraviolet Optical Characteristics of Cotton

two single-pole relays, the chart remains at &dquo;A&dquo; speed, with the selector switch in the &dquo;F~VD&dquo; positiol1¡:md cross head moving up at either speed. If automatic chartspeed change is required under these circumstances, replacement of RU/2 hy&dquo;a double-pole relay (extra contacts shown dotted in Fig. 2) gives the <Insired switching. In the &dquo;KXT/STOI’&dquo; position of the selector switch, automatic chart-speed change occurs with the new switch