Cellulose thiocarbonate-ferric nitrate redox system induced graft copolymerization of vinyl monomers on to cotton fabric

ABSTRACT:The feasibility of a cellulose thiocarbonateazobisisobutyronitrile (AIBN) initiation system to induce graft copolymerization of methyl methacrylate (MMA) and other acrylic monomers onto cotton fabric was investigated. Other acrylic monomers were acrylic acid, acrylonitrile, and methyl acrylate. The initiation system under investigation was highly activated in the presence of a metal-ion reductant or a metal-ion oxidant in the polymerization medium. A number of variables in the grafting reaction were studied, including AIBN concentration, pH of the polymerization medium, nature of substrate, monomer concentration, duration and temperature of polymerization, and composition of the solvent/water polymerization medium. The solvents used were methanol, isopropanol, 1,4-dioxane, cyclohexane, benzene, dimethyl formamide, and dimethyl sulfoxide. There were optimal concentrations of AIBN (5 mmol (2 mmol/L). A polymerization medium of pH 2 and temperature of 70°C constituted the optimal conditions for grafting. The methanol/water mixture constituted the most favorable reaction medium for grafting MMA onto cotton fabric by using the Fe 2ϩ -cellulose thiocarbonate-AIBN redox system. MMA was superior to other monomers for grafting. The unmodified cotton cellulose showed very little tendency to be grafted with MMA compared with the chemically modified cellulosic substrate. A tentative mechanism for the grafting reaction was proposed.

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Grafting of acrylic monomers onto cotton fabric using an activated cellulose thiocarbonate–azobisisobutyronitrile redox system

Zahran

Morsy

Mahmoud

2003

“…When DMAE-MA:HNO 3 was polymerized with cotton fabric the graft yield is directly related to the DMAEMA:HNO 3 concentration within the range studied (from 100 to 400% base on weight of fabric). The percentage of grafting increases almost linearly from 7.76% at 100% DMAEMA : HNO 3 concentration to 26.01% at monomer concentration of 400% DMAEMA : HNO 3 . At higher concentration of DMAEMA : HNO 3 , the gel effect brought about by the solubility of poly (DMAEMA) in its own monomer seems to be more pronounced.…”

Section: Tentative Mechanismmentioning

confidence: 88%

“…3 Hydrosulphide groups (-SH) created along with the cellulose backbone would greatly heighten the reduction power of cotton cellulose. Hence when the cellulose-thiocarbonate is coupled with a strong oxidizing agent such as (NH 4 ) 2 S 2 O 8 an efficient redox-system, able to initiate vinyl grafting on cotton fabrics is established.…”

Section: Introductionmentioning

confidence: 99%

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Modification of cellulosic fabrics to impart flame retardancy properties

Waly

Elmaaty

El-Shakour

2011

Graft copolymerization of dimethylaminoethyl methacrylate (DMAEMA) onto cotton-cellulose in the fabric form was carried out using a cellulose-thiocarbonate-ammonium persulphate redox initiation system. Effects of the concentration of the monomer, effect of liquor ratio, grafting time, and temperature were studied. The results point out the following important aspects of flame retardation of cellulose fabrics. (1) The graft polymerization of DMAEMA can improve the flame retardant properties of cellulose fabrics. (2) Tertiary amine grafted to cellulosic fabrics is suitable for nitrogen compounds that can effectively operate as synergists. The flame retardant properties of the poly-DMAEMA-grafted-phosphorylated cellulosic materials were found to be excellent even after 25 dry clean washings.

Peroxydiphosphate–metal ion–cellulose thiocarbonate redox system‐induced graft copolymerization of vinyl monomers onto cotton fabric

Zahran

Mahmoud

2003

ABSTRACT:The grafting of methacrylic acid (MAA) and other vinyl monomers onto cotton cellulose in fabric form was investigated in an aqueous medium with a potassium peroxydiphosphate-metal ion-cellulose thiocarbonate redox initiation system. The graft copolymerization reaction was influenced by peroxydiphosphate (PP) concentration, the pH of the reaction medium, monomer concentration, the duration and temperature of polymerization, the nature of vinyl monomers, and the nature and concentration of metallic ions (activators). On the basis of a detailed investigation of these factors, the optimal conditions for the grafting of MAA onto cotton fabric with the said redox system were as follows: [Fe 2ϩ , pH-2, grafting time ϭ 2 h, grafting temperature ϭ 70°C, and material/liquor ratio ϭ 1 : 50. Under these optimal conditions, the graft yields of different monomers were in the following sequence: MAA ӷ acrylonitrile Ͼ acrylic acid Ͼ methyl acrylate Ͼ methyl methacrylate. The unmodified cellulosic fabric (the control) had no ability to be grafted with MAA with the PP-Fe 2ϩ redox system. The percentage of grafting onto the thiocarbonated cellulosic fabric was more greatly enhanced in the presence of iron salts than in their absence. This held true when the lowest concentrations of these salts were used separately. A suitable mechanism for the grafting processes is suggested, in accordance with the experimental results.