Color Index Disperse Yellow 42 (DY42), a high-volume disperse dye for polyester, was used to compare the capabilities of the LTQ-Orbitrap XL and the LTQ-FT-ICR with respect to mass measurement accuracy (MMA), spectral accuracy, and sulfur counting. The results of this research will be used in the construction of a dye database for forensic purposes; the additional spectral information will increase the confidence in the identification of unknown dyes found in fibers at crime scenes. Initial LTQ-Orbitrap XL data showed MMAs greater than 3 ppm and poor spectral accuracy. Modification of several Orbitrap installation parameters (e.g., deflector voltage) resulted in a significant improvement of the data. The LTQ-FT-ICR and LTQ-Orbitrap XL (after installation parameters were modified) exhibited MMA ≤ 3 ppm, good spectral accuracy (chi-square values for the isotopic distribution ≤ 2), and were correctly able to ascertain the number of sulfur atoms in the compound at all resolving powers investigated for AGC targets of 5.00×105 and 1.00×106.

Near infrared (NIR) techniques for the measurement of cotton-polyester (PET) blend content have concentrated on yarn slivers and greige fabrics rather than the more difficult application to dyed or printed fabrics. The need for a robust and rapid measurement of the fiber content in dyed cotton-PET fabrics has been expressed by several organizations. Investigations were initiated to develop NIR techniques to measure the cotton content of dyed blend fabrics. NIR measurements were made on dyed or pigmented cotton-PET fabrics that comprised a wide range of cotton content, fabric parameters, and patterns/colors. The samples were analyzed on two NIR instruments at two locations with various reflectance NIR sampling systems. Significant spectral differences were observed for 100% cotton and 100% PET samples, and these spectral differences carried over to the dyed cotton-PET samples with changing cotton content. The impacts of significant differences in baseline were minimized with the use of advanced chemometric normalization techniques. Rapid (less than 5 minutes) and accurate NIR measurements of the blend content in dyed cotton-PET fabrics were developed, with a NIRlaboratory method agreement normally within ± 3.0% cotton for nearly 90% and higher of the validation samples.

A new and relatively simple method for removing zinc nitrate-cured DMDHEU crosslinks from cotton cellulose is reported. The method entails boiling the finished fabric in 23% NaOH for 10 minutes. Removal of the finish was verified by nitrogen and formaldehyde analyses and by wrinkle recovery measurements. Little change

The growing importance of polymer chemistry in higher education has been underscored by recent articles in THIS Journal. An initial series of papers on the development of polymer chemistry (1-3) was followed by an entire issue devoted to that subject (4). In addition to several articles on "basic principles of polymer chemistry," there were papers dealing with "aids to learning and teaching polymer chemistry." A third excellent series dealt with some areas of current research in polymer characteristics and properties, e.g., molecular weight and molecular weight distribution (5), morphology (€>), rheology (7), mechanical properties (8), and rubber elasticity (9). A very important characteristic of amorphous polymers, the glass transition temperature (Tg), was discussed briefly (8). The intent of this article is to present general glass transition temperature information in hopes that it can be used in the same educational maliner as that found in the previously referenced papers. Detailed reviews on this subject can be found elsewhere (10-13).

Cotton fabrics treated with various alkylated derivatives of DMDHEU were subjected to hydrolysis by urea-phosphoric acid, hot 23% sodium hydroxide, and urea-phosphoric acid followed by sodium hydroxide. Sequential treatment with acid and base removed more nitrogen and formaldehyde than the alkaline treatment, which removed more nitrogen and formaldehyde than the acid treatment. Stability of the crosslinks generated by these resins depended on both the degree of alkylation of DMDHEU and the nature of the alkyl cap. This stability was reflected in greater amounts of residual nitrogen and formaldehyde after hydrolysis. Those residues, in turn, affected the residual breaking strength, flex abrasion resistance, and wrinkle recovery of the hydrolyzed fabrics. The stability of the crosslinks also correlated well with formaldehyde release data for the treated fabrics.