The efficiency of activation and interaction of styrene with fibrous cotton cellulose was increased by the indirect effects of radiation-excited cotton and of methanol and N,N-dimethylformamide. The high radiochemical yields indicated that a chain reaction was initiated. The polystyrene was located within the growth layers of the fibers. The elongation-at-break and resistance to wetting of polystyrene-cotton were greater than that of cotton, and the average stiffness, less. The polystyrene-cotton was thermoplastic.THE basis for these studies was the hypothesis that the interaction of polystyrene with cotton could yield products having desirable thermoplastic properties and increased water repellency. Radiationinduced interaction of styrene monomer with cotton would offer the possibility of more than a surface interaction in that monomer could he allowed to diffuse into the fiber prior to polymerization. It has lweii reported that about 63 electron volts of energy are required to produce a free radical of styrene ( 21 J . The aromatic ring in styrene probably tends to stahilize the molecule, resulting in a low efhciency of free radical yield. It can be calculated from data previously published that at f dosage of about 1 megaroentgen, in an oxygetl atmosphere, about 14 electron volts of energy are required per scission of the cotton cellulose molecule )6. 11, 12 [ . It t is s generally assumed that radiochemical reactions of organic molecules ia a solid state are due entirely to free radicals [13{. Obviously, then, if 5ignificant interaction of styrene with cotton is to be initiated hy high-energy radiation and at, the same time the fibrous structure of the cotton is to be retained, the efhciency of the radiochemical yield for activated styrene must 1e increased.A number of reports on the interaction, upon high-energy irradiation, of styrene with cellulose --~--~--films [ 14, 16 j, filter paper ( 1-1, 23 [, cellulose esters ( 25, 26, 27], cotton [18, 19, 20, 23 ] , and regenerated cellulosic fibers , [ 5, 20, 24 ~ have been pullished. The swelling of the cellulose with water [241 J and the immersion of cellulose in solutions of hydrogen peroxide [18, 19] and of formamide and methanol ( 5, 20, 24 during irradiation have been claimed to increase the interaction of styrene and cellulose. Radiation dosage levels used to induce interaction of styrene with cellulose would, in most cases, result in the depolymerization and loss of the fibrous structure of cotton.The indirect effects of radiation-excited cotton, in the presence of methanol and :~',:~'-dimethylforntaiiiide, on the efficiency of activation and interaction of styrene with fihrotts cotton cellulose are discussed in this report. The effects of the interaction of styrene with cottoa on its textile properties are also reported., . , Experimental Alaterials Deltapine cotton, spun into 7s/3 yarn and wound into 18-yd skeins, each weighing 4 g, was purified by extraction with hot ethanol followed hy boiling in 1 ~/~ ~ aOH solution, with proper precautions to prevent...

THE preparation of radiation-induced graft p l y -Experimental of cotton cellulose, without loss of the fibrous Afaterials structure of the cotton, has been reported by this laboratory 12, 3, 4, 6, 71. ~t has heen sllown thatThe chemical and niechanical properties of the the structure of the cotton fibers can by gmft plymers of cotton used in this investigation formation of graft polymers with acrylonitrile and are slmwn in Table I. Detailed descriptions of their styrene, the polymers being located within the lumen preparation and proprties have been previously reand growth layers of the fibers. At dosages of high-ported for purified cotton 181, graft P~~s of energy radiation of less than one megaroentgen, the acrylonitrile and ~urified cotton 12, 3.41, graft P&" fibrous products have significant,y decreased s t i~-m e n of acrylonitrile and cyanoetllylated cotton [7], nesr, significantly increased elongation-at-break, deand Vaft polymers of styrene and purified cotton 161.creased permanent set, decreased breaking toughness, and slightly decreased breaking strength. These etlrOds changes in properties, particularly stiffness, elonga-Textile tests were done according to ASTM nletlltion-at-break, and permanent set, indicate changes ods [I], and other tests were done as in the cohesive forces of the cotton cellulose.Changes in the cohesive forces of the cellulose TIle tllermal stress &havior of the graft polymers could indicate changes in the mechanical bhavior of of fibrous cotton cellu,ose was deterlnined on podthe radiation-induced graft polymers of cotton that ucts that were in the form of 7s/3 yarns. An Inwould be of importance to their usefulness as textiles. stron t equipped an environmental test Particularly, their usefulness as thermoplastic texwas used to determine changes in of tlw tiles may be indicated. In this report, the secondprducts ,vith cllanges in tenlpeature. T11e results order transition tenlperatures .of selected radiationwere evaluated in a manner sinlilar to interpreinduced graft polymers of fibrous cotton cellulose are tation of second-order transition tell~perature and presented, and the thernial stress lxllavior of these f i l~r properties by Drown 151.products is discussed.

No abstract

In the course of investigations involving the determination of the effects of gamma radiation on cotton cellulose [ 1, 3, 4 J and on polymerization of vinyl monomers [ 2 J , a technique for the application, or possibly grafting, of large, controlled quantities of polyacrylonitrile onto cotton has been developed. Acrylonitrile monomer was uniformly applied to purified 7/'3s yarn, Deltapine cotton, and then polymerized by gamma radiation from cobalt-60. The yarns were extracted overnight by N,N-dimethyl formamide at 25° C. to remove any monomer and soluble or loosely bound polymer. Raw yarns were also similarly treated to determine the effects of radiation polymerization of monomer onto raw cotton.As shown in Table I, by use of aqueous ZnCI2 as the solvent relatively large quantities of acrylonitrile monomer could be applied to the raw yarns and radiation polymerized onto the raw cotton. . -_

SynopsisWhen effect of the substrate is nullified, resiliency can be defined as a function of strain, time, and humidity. Determination of improvement in the immediate, or rapid, tensile recovery readily delineates differences due to chemical modifications. Delayed recovery is usually less improved than immediate. Crosslinking cotton with dimethylolethyleneurea (DMEU) increases tensile strain recovery as the number of crosslinks increase, reduces dependency of recovery upon external strain, and produces maximum recovery at about 65% R.H. Noncrosslinking treatments produce limited increases in tensile strain recovery. Measurements on yarns crosslinked with DMEU and then hydrolyzed indicate that incalculably few residual links may contribute to tensile recovery. A'-Methylol-S'-methylethyleneurea treated cotton displays physical blocking and water swelling which aid recovery. Oleoyl chloride esterified cellulose has tensile recovery probably due to molecular entanglement?. Its delayed or viscoelastic recovery is the most improved with immediate recovery being the least improved. The higher the moisture regain, the greater tensile modulus reduction under wet conditions. Crosslinking with DMEU under dry conditions lessens this reduction in modulus. Improvements in the tensile recovery of strain and energv, for all samples and with varied conditions of humidity and strain, correspond linearly with unit slope.