Robert F. Schwenker

The Differential Thermal Analysis of Textile and Other High Polymeric Materials

° tions occurring at teml>eratures below 300° C. [4, 9, 101, with the exception of work by Nlorita [131 ] and a very recent paper by Andersen and Freeman [11. Very little is reported on textile fihers ( 5, 19], and no detailed study of the high-temperature degradation of textile materials by UTA has been reported in the literature at thy writing. Fiber and fabric samples of 75-150 mg. were heated at a rate of 10° C./min. from room temperature to 550° C. The technique and apparatus employed were based on the work of Cordon and Campbell and others [7, 17] and will be described at a later date. The results obtained have been shown

Differential Thermal Analysis of Protein Fibers: Textile Research Institute Princeton, New Jersey, May 31, 1960

1. Alexander, E., Lewin, M., Musham, H. V., and Shiloh, M., TEXTILE RESEARCH JOURNAL 26, 606617 (1956). 2. Gupta. V. D., J. Polymer Sci. 26, 110-112 (1957). 3. Lewin. M., Shiloh, M., and Banbaji, J., TEXTILE RESEARCH JOURNAL 29, 373-385 (1959). 4. MacMillan, W. C., Sen Gupta, A. B., and Mazumdar, S. K., J. Textile Inst. 45, T703-T715 (1954). 5. Rebenfeld, L. and Virgin, W. P., TEXTILE RESEARCH JOURNAL 27, 286-298 (1957). 6. Roy, M. M., J. Textile Inst. 44, T44-T52 (1953). 7. Sen, R. K. and Chowdhury, S. K., TEXTILE RE-

6,6′-Disulfide Cross-Links in Cotton Cellulose; Part II: Effects of Different Cross-Linking Conditions1

The effects of covalent, intermolecular cross-linking resulting from the introduction into cellulose of thio (SH) groups which are subsequently oxidized to form disulfide (S—S) linkages between the cellulose chains are discussed. When the reactions described herein are carried out on cotton fabrics, there is enhanced wet and/or dry wrinkle recovery, depending upon the mode of thio group oxidation. The results of oxidation in aqueous, nonaqueous, and gas-phase systems are compared. The relation between the degree of cross-linking and wrinkle recovery is described in quantitative terms. The effects of intermediate reactions and disulfide cross-linking on strength as well as on wrinkle recovery are also described.

The Effect of Chemical Modification on the Flame and Glow Resistance of Cotton Cellulose

this laboratory furnishe(1 the data to &dquo;&dquo;pport a theory of ce)!u!ose (Iecomposition at elevated temperatures 171. !his theory su~~ests the proxima! cause of the nanuuahihty of the ce!!u!ose polymer to he the (I(-composition during tlwrmal degradation of an intermediate product. ! .6 anhydro-~ o-~htcopyranosc ( lcv (ylur~ ~~:u~ 1, to yield volatile and nammahte products, Tltit rt-seircli gave rise to the working hypotl1t’:-.is that suitable chemical modification of the primary alcohol group at the 6 carbon of the ~11tC:o...e anhydride unit of the cellulose chain should prevent the formation of levogltucosan in those glucose resin-

Grafting of Preformed Polystyrene onto Cotton Cellulose

Grafting of preformed polystyrene onto cotton cellulose has been investigated. Low molecular-weight, carboxyl-terminated polystyrene was synthesized by anionic poly merization techniques and polymers with DPn ranging between 9 and 120 were obtained. Grafting was achieved by reaction of the acyl chloride derivatives of the carboxyl- terminated polystyrene with cotton yarns and fabrics. Graft copolymers with low molecular-weight side chains and relatively high degrees of suiostitution were obtained. The grafting degree of substitution was mainly dependent on the molecular size of the reacting preformed polymer, whereby high molecular-weight preformed polymers lead to low degrees of substitution. Wrinkle recovery and water of imbibition of the modified fabrics and yarns were determined.

Chemical Structure of Resin-Treated Cellulose1 Part I: Trimethylolmelamine-Treated Cotton

The nature of the interaction of trimethylolmelamine resin with cotton substrates, arising from the dry curing (ca. 140° C for 4 min) of the resin on cotton, has been in vestigated. A new chemical analytical method is described for the elucidation of the chemical structure of the resin-treated cottons. It is expected that this method will constitute the basis of a general method for the chemical structural analysis of resin- treated celluloses. Data are presented which show cheruical evidence for covalent bonding of the resin to cellulose and that some of the cellulose hydroxyl groups at each position, i.e., C6, C2, and C3, are involved in resin substitution (C6 > C2 > C3). The presence of interchain cross links is indicated. The results also indicate lower DS than anticipated from the resin content of the treated cottons analyzed.

Degradation of Cellulose During Mechanical Processing Part III: A Comparison of the Evaluation by Viscometric Methods

Experimental results and methods of calculation used in investigating the hypothesis of degra dation during mechanical processing [8, 14] are re-examined. New data on a cotton whose processing was entirely standard are reported. An analysis of viscometric measurements, calcu lations, and methods of comparison is included. Methods of another laboratory [1, 4] where this same problem has been investigated are compared. The current results indicate that the original findings [8, 14] are substantiated in concept and magnitude.

Degradation of Cellulose During Mechanical Processing Part IV: Size Reduction of Cotton in a Wiley Mill

The degradative effect of the Wiley mill on cotton samples and the variables affecting this action are discussed. It is concluded that one of the most important mill variables is blade spac ing, and that the form of the cotton sample is also of paramount importance. A microscopic examination of fiber segments confirms the latter conclusion. It is possible that the amount of degradation may also be a function of the D.P. of the sample.

Chemical Structure of Resin-Treated Cellulose: Part II: Trimethylolmelamine Bonding with Cotton

The chemical covalent bonding of trimethylolmelamine (TMM) with cotton cellu lose produced under wet and dry curing conditions has been further investigated. The extent of chemical reaction with cellulose and the location of substituents on the anhydroglucose units were determined by an analytical scheme embodying chemical modification, complete hydrolysis, and gas chromatography of the analysis products. High temperature (160°C) curing gave rise to much greater extents of reaction with cellulose than curing under wet conditions. In the case of TMM, reaction at the primary. hydroxyl (C6) predominated at DS 0.16, whereas the major reaction of a methylated TMM having DS 0.30 occurred at C2.

Thermoplasticity and Resilience Through Benzoylation and Cross-Linking

Basic studies have been carried out to define the interrelation between thermoplasticity and resilience in cotton obtained through chemical modifications. Diester cross links, introduced in combination with benzoate ester groups, provided neither satisfactory resilience nor thermoplastic character. When benzoylated cotton, prepared by partial saponification from higher DS values or by the Schotten-Baumann esterification condi tions, was dry-cured with trirnethylolmelamine, the products showed high levels of wet and dry wrinkle recovery, high resistance to abrasion, and displayed thermoplastic char acter as reflected by the fact that heat-set creases could be imparted to them.