Cellulose copolymers, graft

Condensation of an acrylic acid-cellulose graft copolymer with 5-amino-l,10-phe-nanthroline (233) has been utilized to provide polymer (234 Scheme 113) with the phenanthroline ligand oriented optimally for complexation (77MI11110). The polymer was described as exhibiting a strong sorption capacity for Co2+ and Cu2+ ions. 

The properties of cellulosic graft copolymers have been studied to a considerable extent but mainly in the form of grafted fibers or films of ill-defined composition. However, a few properties have been measured on well defined grafts (147). It was found that solutions of cellulose acetate-polystyrene grafts in dimethyl formamide are less tolerant to the addition of polystyrene than cellulose acetate itself. This result was attributed to the greater coil expansion in the case of the graft copolymer. On the other hand, the tolerance of the grafts to each homo-... 

Yasuda, H J. A. Wray, and V. Stannett Preparation and characterization of some cellulose graft copolymers. Part I. J. Polymer Sci. C2, 387 (1963). 

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

A similar evaluation was made for the other series of CA-g-PHAs to establish a general relationship between their molecular architecture and thermal transition behavior [24]. Of particular interest is the finding that the composition dependence of the Tg of the cellulosic graft copolymers was represented well in terms of a formulation based on a comb-like polymer model [29], when CAs of acetyl DS 2 were employed as a trunk polymer. 

In spite of these enormous efforts, there is still no large-scale commercial application of cellulose graft copolymers. The reasons for this situation and the challenge it represents to cellulose and polymer scientists and engineers will be the subject of this introductory paper. It is convenient to break down such a discussion into the following areas, synthesis, characterization, properties and, finally, applications. The discussion will be mainly devoted to cellulose itself, although grafting to cellulose derivatives has also been actively pursued. 

UV light induced grafting onto wood cellulose is reported for several vinyl monomers. The reaction is initiated by free radical initiators such as phenylace-tophenone and benzophenone derivatives. Percent grafting-time conversion curves are determined as a function of the initiators, monomers, pulps and additives. Additional typical results obtained in IR spectroscopy, GPC and thermal analysis are reported. A discussion about the use of a photochemical procedure in obtaining cellulose graft copolymers is presented. 

Teramoto Y., Nishio Y. Structural designing and functionalization of biodegradable cellulosic graft copolymers. Cellulose Communications 77 115-120 (2004). 

Tihe preparation and properties of cellulose graft copolymers have A been of considerable interest in the textile, paper, and wood products industries for a number of years. Both free radical- and ionic-initiated graft copolymerization reactions of vinyl monomers with cellulose have been reported. The vinyl-cellulose copolymers have some of the properties of both the cellulosic fibers and the grafted polyvinyl copolymers (I, 3, 47). 

The modification of the properties of cotton cellulosic textile products, through free radical-initiated graft copolymerization reactions with vinyl monomers, has been investigated at the Southern Laboratory for a number of years (6, 9). In this chapter, we summarize the basic mechanisms and principles involved in free radical reactions of cellulose, initiated by high energy radiation, ceric ion in acidic solution, and aqueous solutions of ferrous ion and hydrogen peroxide. Some of the properties of fibrous cotton cellulose graft copolymers are also presented. 

Ionizing Radiation. When the activation reaction and copolymerization reaction were conducted simultaneously, the fibrous cellulose was first treated with monomer solution and then irradiated. Usually some homopolymer was formed and was removed from the cellulose graft copolymer by extraction with solvent for the polymer. When the activation reaction and copolymerization reaction, were conducted consecutively, the fibrous cellulose was first irradiated and then treated with monomer solution. As compared with the simultaneous procedure, formation of homopolymer was very low.. The changes in the ESR spectra for irra-... 

The molecular relationships in cellulose graft copolymers depended on the method of free radical formation on the cellulose molecule and... 

Table II. Effect of Method of Free Radical Formation and Conditions of Reaction on the Molecular Relationships in Cellulose Graft Copolymers...

The morphology of the fibrous cellulose graft copolymers depended on the method of initiation of free radical formation, experimental conditions during the copolymerization, chemical modification of the cellulose before reaction, and the type of monomer used (60). Variations in the shape of the fibrous cross section, in layering effects in the fiber, and in the location and distribution of the grafted copolymer in the fiber were observed by electron microscopy (61). Cotton cellulose—poly (acrylonitrile) copolymer was selected to show the possible variations in location and distribution of the grafted copolymer in the fiber. 

Some of the important changes in physical properties of cellulose graft copolymers are summarized below. 

Fabrics. Fabrics composed of cellulose graft copolymers had increased flex and flat abrasion resistances as compared with untreated fabrics (1, 31, 35, 36, 37, 47). 

Cellulose constitutes a ubiquitous and renewable natural material that has great potential for chemical conversion into high-quality adhesive products. The resurrection of research and development of cellulose derivatives, such as cellulose esters and ethers, cellulose graft-copolymers, and cellulose polyblends, has instituted new avenues for adhesive applications. There is little doubt that new solvent systems for cellulose have created the potential of developing uniform cellulose products with superior properties for adhesive applications. 

Cellulose Graft Copolymers for Potential Adhesive Applications Bonding of Plastics to Wood... 

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