Textile grafts

Since homopol)rmer had a marked effect on the aesthetic properties of grafted textiles, we considered methods whereby homopol3mier formation could be minimized. Earlier Howard, Kim, and Peters had successfully photografted methacrylic acid vapors on nylon 6 film using benzophenone as photosensitizer (24). They found that the technique was efficient only at low concentrations... 

Aureobasidium sp. are ubiquitous microorganisms. There are approximately 15 species of Aureobasidium. They are found in soil, forest soils, fresh water, fruit, wood, bathrooms and kitchens, on shower curtain, tile graft, textiles, among others, (see Fig. 13.5). Wet spores are disseminated by wind when spores dry out. Many other fungi, Aureobasidium sp. are common allergens (hay fever, asthma, pneumonitis, etc.). Colonies are usually of the shades of cream to pink, becoming dark brown with age. 

Part II Function/Application Index grafting, textile fibers... 

Keywords endovascular prosthesis fatigue resistance in vitro test stent graft textile structure. 

Pourdeyhimi B, Vascular Grafts Textile Structures and Their Performance ... 

In industry, radiation is applied both as an initiator and as a control mechanism on one hand, and as a sustainer of reactions on the other. Among the many industrial uses of radiation, one may mention food preservation, curing of paints, manufacture of wood-plastic combinations, syntheses of ethyl bromide, of ion exchange materials, of various graft copolymers, and of materials for textile finishing. In addition, there are important uses of tracers in various process industries and in mining and metallurgy. 

Polymerization reactions. Polymerization of ethylene to polyethylene has been conducted at pilot-plant scales reaching a target of 1500 tons per year. Some reactions, including polymerization and copolymerization of polymers for grafting on textile fibers, have been successfully performed. Similarly, cross-linking of polyethylene to improve thermal properties has also been achieved. 

Polyacrylonitrile is an excellent textile fibre but is difficult to dye. However, by its copolymerisation or by grafting on a second polymer, it is possible to maintain the desirable properties of the fibre, yet produce a textile which can be processed in the usual way. Among the various factors that govern the copolymerisation process, the concentration and reactivity of the monomer are quite important. At any given time, the chain may grow in four different ways as under. Here A and B are the radicals which are involved in propagating steps, whereas A and B are the respective monomers. 

Although many radiation-grafted materials have been discovered, only a limited number of them have been commercially utilized. One of the first successful applications was the use of grafted films in battery separators. Other possibilities are in ion exchange resins and membranes for separation processes. The textile industry represents opportunities in improving... 

Kamogawa, H., and T. Sekiya Graft polymerization of acrylamide onto cotton fabric for further treatments. Textile Res. J. 31, 585 (1961). 

Polymerization of methyl methacrylate monomer with cobalt-60 as source of y-rays, Free radical formation is involved in both cross-linking and polymerization reactions This technique is also being applied in the textile finishing field for grafting and cross-linking fibers with chemical agents for durable-press fabrics. 

Graft and block copolymers of cotton cellulose, in fiber, yam, and fabric forms, were prepared by free-radical initiated copolymerization reactions of vinyl monomers with cellulose. The properties of the fibrous cellulose-polyvinyl copolymers were evaluated by solubility, ESR, and infrared spectroscopy, light, electron, and scanning electron microscopy, fractional separation, thermal analysis, and physical properties, including textile properties. Generally, the textile properties of the fibrous copolymers were improved as compared with the properties of cotton products. 

Table VII. Properties of Textile Fabrics Containing Cellulose Graft Copolymers...

In the field of true cellulose grafting, there have been numerous attempts at commercialization in the cellulose fiber field. Some have reached pilot stage proportions, others have been full commercial processes such as the Deering-Millikan durable process now apparently in abeyance. Most of these developments have been in the field of textiles. 

In Japan, pilot plant quantities of rayon and cotton grafted with styrene and other monomers have been prepared and evaluated. Improvements in the flex abrasion resistance and good water repellency were obtained. In addition, thermoplasticity was imparted plus an improved adhesion to rubber. Arthur et al. have also studied this type of grafted cellulose fibers. Again, the work has not led to any large scale developments. Research into grafting to textiles is continuing, but the prospects for any early successful industrialization seem remote. 

Grafting to pulp and paper has also been studied but not to the same extent as textiles. A comprehensive review of the field was published in 1972 (39). Many of the useful properties imparted to pulp and paper are similar to those already discussed with textiles. These include the mechanical behavior, ion... 

Grafted cellulose powders such as Solka Floe have been grafted with polyacrylic acid and also rendered cationic by direct chemical reaction (54). Both of these modified cellulose products have been prepared on a large scale. They appear to show considerable promise for the removal of dyestuffs and other charged impurities from waste water such as textile effluents. They are also able to break emulsions of water and organics by removal of the surfactants (55). 

More recently, Gangneux et al (11) developed a method for grafting acrylic acid onto cellulose powder, "Solka Floe," for use in textile waste treatment. The cellulose was treated with ceric ion in aqueous solution prior to its reaction with acrylic acid. A benzene-acrylic acid solution was used for grafting to reduce homopolymerization. Presumably, the hydrated ceric ion would not diffuse into the monomer solution to initiate homopolymerization although the reverse could still take place. They obtained grafting yields up to approximately 70% accompanied by 45% homopolymer. In the present investigation, their method is extended to fibers and additional emphasis is placed on the reduction of homopolymerization. 

---