Cellulose grafting products

Although an appreciable thermoplasticization was realized by the decrystallization treatment, the treatment did not give cellulose graft products which melt upon heating. This lack of melting was confirmed by microscopic observations of films prepared with the decrystallized composites. 

The first application of the ferrous ion-hydrogen peroxide initiation for polymerizing vinyl monomers on and into cellulose fibers has been reported by Landeias and Whewell (41) in three successive papers. They are apparently the first who applied the "anchored catalyst technique, which other people have termed "in situ polymerization to cellulose grafting. The authors internally deposited methyl methacrylate, acrylonitrile, styrene, methyl vinyl ketone and methacrylamide in amounts between 10 and 80%. No attempt had been made to determine if actual grafting had occurred. In 1961 Richards (42) studied this question in great detail. Products obtained by polymerization of acrylonitrile and of styrene in viscose rayon were acetylated. Fractionation of... 

Daniel, Moore, and Segro (49) further investigated the graft polymerization of acrylonitrile to paper. They found that in grafted products having add-ons up to 53% neither cellulose nor polyacrylonitrile could be extracted with respective solvents. 

Kamogawa, and Sekiya (54) studied the graft polymerization of acrylamide onto cotton fabric using ceric ammonium nitrate as the catalyst. Similarly to Kulkarni et al. (35) the authors performed subsequent cross-linking with formaldehyde amd methylol compounds. From precipitation studies by acidification of cuprammonium solutions on mixtures of polyacrylamide and cellulose on the one hand and polyacrylamide-cellulose grafts on the other the authors conclude that chemical bonds must exist between the two polymers in the grafted product. 

Morphological or supermolecular structure is the most easily changed property of cellulosic fibers. Interactions of selected monomer solutions with fibers can yield grafted products... 

Grafting and hydrolysis proceed as efficiently for cellulosic substrates as previously found for starch and water soluble polysaccharides. The grafted and hydrolyzed cellulose-based products prepared by the methods described, are of potential technical interest for water retention in various applications. 

Cotton cellulose (1 g) was allowed to stand with 1 % aqueous solution of ammonium persulfate (0.5 g) for 30 min at room temperature Methyl methacrylate (MMA) (20 ml) and methanol (20 ml) were added to the mixture. After degassed, the flask was sealed and shaken at 60 °C for 1 to 4 h. The graft product was isolated by pouring into a large excess acetone followed by Soxhlet extraction with acetone for 48 - 72 h. 

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. 

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. 

Results from the initial resin studied are also being employed in the development of additional experimental procedures. Plans are currently being drafted to prepare three-ply test specimens that are similar to the specimens used in the initial study, with the middle ply consisting of solid polystyrene. Comparing specimens with and without the graft polymers introduced to the ply interfaces should provide additional information on the ability of the cellulosic graft polymers to facilitate bonding between wood and plastic materials. If this approach proves successful, additional procedures will then be developed for the production of simple composite specimens. 

Since the 1960 s many researchers have been concerned with the development of feasible and industrially useful methods for the synthesis of cellulose graft copolymers3, 4. Recent investigations have shown that the most efficient approach to this problem involves free radical polymerization initiated by redox systems5. An impressive example is the industrial production of mtilon (cellulose-polyacrylonitrile graft copolymer) and other fibers, particularly those with ion-exchange and acid-resistant properties6"8. ... 

Experience on the industrial production and use of mtilon and, of late, other fibres based on cellulose graft copolymers (e.g. ion-exchange fibres and fibres resistant to aggressive... 

Blends with cellulose have attracted some attention [Plaque and Montserrat, 1991]. The degradation characteristics of blends with PAN were found to be superimposable with those of the pure components, however grafted products showed reduced thermal stability [Nishioka et al.,... 

Somewhat similar results were obtained with cellulose graft/blend systems with PMA, PMMA and poly(2-hydroxyethyl methacrylate) [Nishioka and Yoshida, 1992] and could be correlated with the degree of compatibility. In one case the thermal stability of blends containing grafted cellulose was 100°C less than those without grafted product [Nishioka et al., 1993]. 

Johannesson, S. GLP production in bioreactor and evaluation of cellulose grafts. CHALMERS Chemical and Biological Engineering. http //www.ehalmers.se/chem/EN/ divisions/biopolymer-technology/tissue-engineering/bbv-scientific-teams, visited 07/02/2011... 

Cellulose has been considered as an attractive alternative to produce fuel, chemicals, and functional materials. In long-term research, the integrated production of fuel and fine commodity chemicals from cellulose would be a preferred choice. Several functional materials based on cellulose derivatives or cellulose graft copolymers have already been designed successfully however, more work still needs to be done to make them more practical. 

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