Fibrous cellulose-polyvinyl copolymers

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. 

Figure 2. Effect of temperature on the relationship between energy expended to elongate fibrous cellulose-polyvinyl copolymers ana energy recovered on relaxation of the copolymers. (See Figure 1 for identification of copolymers.)...

As reported previously, the morphology of fibrous cellulose-polyvinyl copolymers, determined by electron microscopy, depends on the method of free-radical initiation of the copolymerization reaction, the experimental conditions during the reaction, and the type of vinyl monomer used. Variations in the shape of the fibrous copolymer cross section, in layering effects in the copolymer structure, and in location and distribution of the polyvinyl polymer within the fibrous structure were shown (1,2,7,29,52). 

Solubility of cellulose in the products has also been used to indicate the presence of covalent bonds between cellulose and the polyvinyl copolymer. Thin sections of fibrous cellulosic copolymers, as prepared for electron photomicrography, are examined both before and after successive extractions with solvents for cellulose and for the polymer. The presence of undissolved cellulose and polymer in the extracted thin section is interpreted as evidence for the presence of covalent bonds and for grafting (52). 

The modification of the properties of fibrous cotton cellulose through free-radical initiated copolymerization reactions with vinyl monomers has been investigated at the Southern Laboratory for a number of years. Both graft and block copolymers are formed. Under some experimental conditions the molecular weight of the polyvinyl polymer, covalently... 

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