Textile Research Journal

A relationship between the bulk density and the compressive force within a bed of loose fibers rotating inside a centrifuge is derived. The relationship is the same as the one for compressing loose fibrous assemblies with a piston in a vertically mounted cylinder, using an Instron tester. The value of empirical constants in the relationship for a particular type of fiber is practically identical in both cases.

The hand of some spunbonded and spunlaced nonwovens is analyzed. Laboratory tests were conducted and subjective evaluations made to compare the hand of these nonwovens with the hand of some woven fabrics sold into apparel applications. Relationships between hand and quality words such as smoothness, stiffness, and weight are analyzed. Additional correlations are made with measured fabric prop erties, including flex stiffness and elastic modulus. An empirical equation is devel oped for computing hand from simple instrument readings.

A theoretical analysis is presented of the load-elongation behavior of a crimped filament, whose axes lie in a two-dimensional plane. The crimp shapes considered are ideal and very closely related to those produced by some texturing processes.

A second order nonlinear differential equation describes the deformed shape of the crimped filament, which is subjected to a terminal load in its axial direction. Numerical solution of the equation uses Maclaurin's series. The analysis describes the deformed shape and the load-elongation behavior of two-dimensional crimps. such as zigzag, gear-tooth, semicircular, and knit-de-knit crimps.

The theoretical analysis is verified experimentally by heat setting polyester and nylon 6 monofilaments in zigzag and gear-tooth crimps of different amplitudes and wavelengths. The values obtained from the theoretical analysis have excellent cor relation with the experimental results.

Hollow rayon and polypropylene fibers have been modified to change their heat capacity dramatically in an ambient temperature range (270-310 K) by filling them with aqueous solutions of calcium chloride hexahydrate/strontium chloride hexa hydrate capable of producing latent heat gains and losses in the modified fibers during repeated heating and cooling. Both fibers produced large endotherms in the heating cycle (303 K) that were dependent on the relative humidity at which the fibers were previously conditioned; however, only the modified rayon fibers exhibited a significant exotherm in the cooling cycle (282 K). Endotherms and exotherms for modified rayon fibers (previously conditioned at 45% RH) persisted even after 10 heating and cooling cycles. Apparently, hydrophilic differences in the two fiber types require different amounts of water in the salt system of the dried and conditioned fiber to produce reversible latent heat gains and losses caused by heats of fusion and crystallization of the salt system. Neither the unmodified fibers nor another aqueous salt system incorporated into the fibers (sodium sulfate/borax) exhibited any sig nificant endothermic or exothermic changes on heating or cooling.

A cotton drill fabric of 348 g/m² was finished with DMDHEU from anti-crease to durable press level using a shock-cure technique employing a loop transfer pad with resultant low wet pickup of 40% and an active mixed catalyst system. A con ventional pad-dry-cure (PDC) treatment was also used. Evaluation of fabrics finished by the transfer-pad-cure (TPC) and PDC techniques shows that TPC leads to higher fixed N₂% with better performance in resilience properties. A comparison of the two techniques using a performance profile chart reveals that the TPC technique shows better performance at lower levels of improvement in resilience, and it narrows down as the resilience approaches the durable press level. This is attributed to the slightly swollen state of DMDHEU crosslinked fibers obtained with the TPC technique.

An electronic test apparatus was designed for measuring winter heat flow through windows with and without interior insulating window coverings. The method pro vides reasonably accurate data on and the insulating effectiveness of various shades and draperies. The test data correlate well with results from other, more expensive and time consuming test methods.

The medium and long term irregularities in ring spun and open end (OE) spun yarns are compared. The medium term irregularity was measured by an inert test in an Uster Evenness Tester using different material speeds, and long term irregu larity was assessed using the cut and weigh method. The results show that not only short and medium term irregularity but also long term irregularity are brought down substantially in OE spinning. This leads to the significant conclusion that the ir regularity added in a ring spinning system comes not only from drafting waves but also from other causes which are absent in OE spinning.

Identification of components of cotton mill dust is a major problem in the search for the causative agent of the chronic lung disease, byssinosis. In the mechanical processes that produce respirable dusts, most of the particles lose all morphological features, making it difficult to determine their source. Workers have used the nat urally occurring elemental content of the various cotton plant parts to show their presence in collected mill dusts. Elemental content of dust particles from known cotton plant parts was determined by electron microscopy-energy dispersive X-ray analysis and by X-ray fluorescence spectroscopy. Potassium and calcium content were used to differentiate leaf and bract materials from stem, seedcoat, and pericarp materials. Particles with elemental content patterns similar to these two groups were present in dust generated in a cotton cardroom. Cottonseed oil mill dusts showed fewer leaf-like particles but more mineral material.