Methacrylic Acid

Graft copolymerization of methacrylic acid (MAA) onto cotton fabric using tetravalent ceric ion (CeIV)–cellulose thiocarbonate redox system was investigated under different conditions including pH of the polymerization medium (1–4), ceric sulphate (CS) concentration (4–20 m mole/l), MAA concentration (1%–6%), polymerization time (1/4–2 h) and polymerization temperature (0–70°C). Results obtained indicated that the optimal conditions for MAA grafting onto cotton fabric using the said redox system consisted of: [CS], 20 m mole/l; [MAA], 4%; pH of the medium, 2; time, 2 h; temperature, 60 °C keeping a material-to-liquor ratio at 1:0. Applying optimized conditions to different monomers, namely, acrylic acid (AA), methacrylic acid (MAA), acrylamide (Aam), acrylonitrile (AN), butyl acrylate (BuA), methyl methacrylate (MMA), ethyl methacrylate (EMA) and glycidyl methacrylate (GMA) onto the same substrate, the rates of grafting followed the order: $$ {\text{GMA MMA }} > {\text{ AA }} > {\text{ MAA }} > {\text{ Aam }} > {\text{ EMA }} > {\text{ AN }} > {\text{ BuA}} $$ A scheme for the mechanism of initiation, propagation and termination reactions was proposed.

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: [Fe2+]= 0.1 mmol/L, [PP] = 2 mmol/L, [MAA] = 4%, pH=2, grafting time = 2 h, grafting temperature= 70°C, and material/liquor ratio = 1 : 50. Under these optimal conditions, the graft yields of different monomers were in the following sequence: MAA > acrylonitrile > acrylic acid > methyl acrylate >methyl methacrylate. The unmodified cellulosic fabric (the control) had no ability to be grafted with MAA with the PP–Fe2+ 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.

Polymerisation of  methacrylic acid (MAA) with cotton fabric using cellulose thiocarbonate-KBrO3 redox system was investigated. The polymerization reaction was studied with respect to graft yield, homopolymer formation, total conversion and grafting efficiency. These polymerization criteria were found to depend largely on concentrations of KBrO3 and MAA, pH of the polymerization medium, duration and temperature of polymerization. Optimal grafting conditions consisted of [KBrO3], 0.1 mole/l ; [MAA], 6% ; time, 60 minutes ; temperature, 60oC using a material to liquor ratio 1:50. Applying these conditions to different monomers, the rates of grafting followed the order: methylmethacrylate > methacrylic acid > methylacrylate > acrylonitrile > acrylic acid.

Cellulose thiocarbonate was prepared by reacting cotton cellulose fabric with carbon disulphide in the presence of sodium hydroxide. The treated fabric formed, with pentavalent vanadium ion, an effective redox system capable of initiating grafting of methyl methacrylate (MMA) and other monomers onto the cotton fabric. The dependence of grafting on vanadium concentration, pH of the polymerization medium, temperature and duration of grafting, nature and concentration of monomer, and solvent/water ratio was studied. Theresults indicated that increasing the pentavalent vanadium (Vv) concentration up to 60 mmol/L was accompanied by enhancement in the rate of grafting; the latter was notaffected by further increase in Vv concentration. Maximum grafting yield was achieved at pH 2; grafting fell greatly at higher pH. The rate of grafting followed the order: 70" > 60" > 50°C. The graft yield increased significantly by increasing the MMA concentration from0.5 to 5%. Of the solvents studied, n-propanol and isopropanol enhanced the grafting rate provided that a solvent/water ratio of 5:95 was used; a higher solvent ratio decreased the magnitude of grafting. Other solvents, namely, methanol, ethanol, n -butanol, and acetone,in any proportion, decreased the rate of grafting. With the monomer used, the graft yield followed the order: methyl methacrylate > methyl acrylate > methacrylic acid > ethyl methacrylate > acrylic acid. Also reported was a tentative mechanism for vinyl-graft copolymerization
onto cotton fabric using cellulose thiocarbonate- Vv

— The synthesis of polyoxychloropropylenepoxymethacrylate oligoesters by esterification of polyoxychloropropylenetriepoxide by methacrylic acid has been carried out. It has been established that by varying the conditions of carrying out of the reaction, one can prepare, mainly, the mono-, di-and trimethacrylic oligoesters. On the basis of epoxy diane ED-20 and synthesized polyoxychloropropylenepoxymethacrylate oligoesters as modifiers there have been prepared the self-extinction compositions, which after curing by N, N 1 –diaminodiphenylsulfone possess higher physical-mechanical, adhesion and heat-physical properties.

Graft copolymerization of methacrylic acid (MAA) onto cotton fabric using tetravalent ceric ion (CeIV)Ycellulose thiocarbonate redox system was investigated under different conditions including pH of the polymerization medium (1-4), ceric sulphate (CS) concentration (4-20 m mole/l), MAA concentration (1%-6%), polymerization time (1/4-2 h)and polymerization temperature (50-70oC). Results obtained indicated that the optimal conditions for MAA grafting onto cotton fabric using the said redox system consisted of: [CS], 20 m mole/l; [MAA], 4%; pH of the medium, 2; time, 2 h; temperature, 60oC keeping a material-to-liquor ratio at 1:50. Applying optimized conditions to different monomers, namely, acrylic acid (AA), methacrylic acid (MAA), acrylamide (Aam), acrylonitrile (AN), butyl acrylate (BuA), methyl methacrylate (MMA), ethyl methacrylate (EMA) and glycidyl methacrylate (GMA) onto the same substrate, the rates of grafting followed the order:
GMA > MMA > AA > MAA > Aam > EMA > AN > BuA
A scheme for the mechanism of initiation, propagation and termination reactions was proposed.

The cellulose thiocarbonate, in the fabric form, was treated first with a freshly prepared ferrous ammonium sulphate (FAS) solution. The so-treated fabric formed, with N-bromosuccinimide (NBS), an effective redox system capable of initiating grafting of methyl methacrylate (MMA) and other vinyl monomers onto the cotton fabric. The effect of the polymerization conditions on the polymer criteria, namely, graft yield, homopolymer, total conversion, and grafting efficiency, was studied. These polymer criteria were found to depend extensively upon concentrations of the Fe2+ ion (activator), NBS (initiator), and MMA; pH of the polymerization medium, and duration and temperature of polymerization. Based on detailed investigation of these factors, the optimal conditions for grafting were as follows: Fe2+, 1x 10-3 mol/L; NBS, 1 x 10-2  mol/L; MMA, 4%; pH, 2; polymerization time, 150 min; polymerization temperature, 60oC; material/liquor ratio, 1 : 100. Under these optimal conditions, the rates of grafting of different vinyl monomers were in the following sequence: methyl methacrylate % methyl acrylate > acrylonitrile. Other vinyl monomers, namely, acrylic acid, and methacrylic acid have no ability to be grafted to the cellulosic fabric using the said redox system. A tentative mechanism for the polymerization reaction is suggested.