Homogeneous graft copolymerization of acrylonitrile (AN) and of methyl methacrylate (MMA) onto cellulose was carried out in a dimethyl sulfoxide-paraformaldehyde solvent system. Ammonium persulfate (APS) and azobisisobutyronitrile (AIBN) were used as radical initiators. The optimum grafting condition for each monomer-initiator system was determined from experiments in which temperature and concentrations of initiator, monomer, and cellulose were varied. The grafting yield for the AN-APS system was higher than that for the MMA-APS system. The grafting onto cellulose hardly proceeded in the AN-AIBN system, but appreciably in the MMA-AIBN system. The grafting of MMA proceeded similarly either with AIBN or APS as the initiator. It was found that the chain transfer from PMMA homopolymer radicals to backbone cellulose occurred. The number of grafts per cellulose chain was found to be in the range from 0.5 to 3.9.

ABSTRACT:The homogeneous graft copolymerization of acrylonitrile onto cellulose was carried out in a dimethyl sulfoxide (DMSO)-paraformaldehyde solvent system. Three kinds of membranes were prepared: higher grafting efficiency membranes (H-GE membrane), lower grafting efficiency membranes (L-GE membrane), and blended membranes. The diffusive permeability of solutes through the water-swollen membranes was investigated. The permeability and microphase separated structure depended remarkably on the kind of membrane. Permeability through the H-GE membranes increased with increasing polyacrylonitrile content and leveled off, but that through the L-GE and blended membranes decreased. Permeability through the H-GE membranes was superior to that through the cellulose membrane cast from the DMSO solution of cellulose. However, the good permeability through the H-GE membranes could not be explained by the difference in water content of membranes.KEY The commercial regenerated cellulose membrane, Cuprophan, produced by the cuprammonium process has been widely used as a hemodialysis membrane owing to its good solute permeability and mechanical strength. However, it is also recognized that the diffusive permeability of solutes of molecular weight ranging from hundreds to thousands is not so good. mechanical strength of the membranes. To produce membranes of good permeability and mechanical strength, many studies have been carried out on amphiphilic copolymer membranes having the proper composition of hydrophilic and hydrophobic regions which function to control solute permeation and support the membrane, respectively. 4 -10

Homogeneous graft copolymerization of acrylonitrile and of methyl methacrylate onto cellulose using radical initiators was carried out in a dimethyl sulfoxideparaformaldehyde solvent system. The graft copolymers obtained under various grafting conditions were hydrolyzed to isolate the graft polymers. The molecular weight of graft polymer and the number of grafts per cellulose chain were determined as functions of polymerization temperature and concentrations of monomer and initiator. The molecular weight of graft polymer increased with increasing monomer concentration but decreased with raising temperature and with increasing initiator concentration. The number of grafts increased with raising temperature and with increasing initiator concentration but decreased with increasing monomer concentration.

Homogeneous graft copolymerization of methyl acrylate (MA) onto cellulose was carried out in a dimethyl sulfoxide-paraformaldehyde solvent system. Ammonium persulfate (APS), benzoyl peroxide (BPO), and azobisisobutyronitrile (AIBN) were used as radical initiators. The optimum grafting condition and the number of grafts per cellulose chain for each monomerinitiator system were determined as functions of polymerization temperature and concentrations of monomer, initiator, and cellulose. Grafting onto cellulose proceeded in the MA-APS system, but hardly at all in the MA-BPO and MA-AIBN systems. The number of grafts was found to be 1.5 at most in the MA-APS system. BPO was found unsuitable as a grafting initiator due to the degradation of the cellulose chains. KEY WORDS Homogeneous Grafting I Cellulose I Methyl Acrylate I Dimethyl Sulfoxide-Paraformaldehyde Solvent System 1 Grafting Percentage I Grafting Efficiency I Number of Grafts 1

SYNOPSISElectropolymerization of o-toluidine ( o-methylaniline ) and m-toluidine was carried out in acidic aqueous solution, and UV-visible and IR spectra of the resulting polymer films were obtained at various electric potentials and pHs. In Na2S04 aqueous solution, poly (o-toluidine ) gave considerably different UV-visible spectra from polyaniline, whereas, in HCl (pH -0 ) , the spectra of poly( o-toluidine) changed in the same way as polyaniline when the potential was varied. This spectral change depended also on counterion. This suggests that the intermediate state (radical cation) of poly (0-toluidine) is unstable in a neutral solution especially when a large counter ion exists, which is contrast to polyaniline. The dependency of the FT-IR spectra of poly( o-toluidine) on the potential and pH supported also the above result of UV-visible spectra. From both UV-visible and IR spectra under various conditions, it was found that o-toluidine and m-toluidine give the same polymer.