The role of additives in the radiation induced copolymerization of monomers to cellulose

Abstract

SYNOPSISThe radiation induced grafting of monomers to cellulose using a variety of solvents by the mutual irradiation technique is discussed. The monomers studied were styrene, 15 substituted styrenes, methylmethacrylate, vinyl acetate, and the vinylpyridines. The types of substituents examined included 0-, m-, and p-halogen derivatives, also the alkylstyrenes and certain methoxy monomers. The effect of wetting and nonwetting solvents in the grafting reaction was also investigated. A Trommsdorff effect (accelerated grafting) has been observed in certain systems at low doses and dose rates. The effect of oxygen, nitrogen, and vacuum on the Trommsdorff peak is discussed. The role of additives in the grafting of styrene is considered. The additives examined include aromatic and nonaromatic compounds, also typical free radical scavengers such as hydroquinone and thiourea. With certain additives sensitization is observed. A model for the grafting mechanism is proposed involving charge transfer bonded species. The role of energy transfer and free radical processes in the copolymerization reaction is also discussed.*Part XI11 of a series, "Radiation-induced Reactions with Cellulose". ~~~ ~~ ~~ ~ astrips were sometimes "lost" due to insolubility of associated homopolymer.

Radiation-induced grafting of vinylbenzyltrimethylammonium chloride (VBT) onto cotton fabric and study of its anti-bacterial activities

“…It is clear from the figure that the order of decrease in the grafting yield with different organic alcohols mixed with water in the grafting solution is methanol 4ethanol4 n-propanol 4iso-propanol4 tert-butanol. It has been reported that solvents can affect the grafting yield in three different ways namely (i) they can act as good wetting (swelling) agents for the polymer backbone (Dilli et al, 1972) and enhance the monomers approach to the active sites, promoting the grafting reaction. (ii) Alcohols can act as an effective chain transfer agent, hence may quench the radical sites generated on the substrate polymer and result in decrease of grafting yields (Lawrence and Verdin, 1973).…”

Role of additive HCL in the radiation‐induced grafting copolymerization of acrylic acid and sodium styrene sulfonate to high‐density polyethylene

“…During this period, Trommsdorff phenomenon 12 come into being. When grafting styrene to polyolefins 4 and cellulose, 13 Trommsdorff phenomenon was observed. In preirradiation method, the quantity of radicals in the matrix is decided by radiation dose.…”

Characterization of Methyl Methacrylate Grafting onto Preirradiated Biodegradable Lignocellulose Fiber by γ‐Radiation

“…The nonlinear dependence of grafting on radiation dose is an inherent characteristic of radiochemical yields in polymers, such as grafting of acrylamide onto preirradiated cellulose acetate. [13] Effect of Temperature at Different Concentrations of MMA For this study, the samples were irradiated to a total dose of 50 kGy at 5 kGy h À1 in the presence of air. The grafting solution was prepared with three different concentrations of MMA and deionized water (i.e., the ratio of MMA to deionized water ¼ 5/95, 7.5/92.5, and 10/90) while other chemical conditions were kept the same as for the radiationdose-dependent grafting.…”

“…In the past, research has been focused on graft copolymerization of vinyl monomers onto natural cellulose and synthetic polymers by using the high-energy radiation method. [11][12][13][14] This study is focused on the preirradiation technique in an aqueous phase because of the lower homopolymer formation in this system and the high level of graft weight that can be achieved.…”

“…These decompose at an elevated temperature to give peroxy radicals for the subsequent graft copolymer reaction. Gamma-radiation-induced grafting of vinyl monomers with other cellulose materials has been investigated [13,[15][16][17][18] extensively under various conditions with different solvents. In most cases, organic solvents are used to dissolve the monomer as well as being good swelling agents for the cellulose materials.…”