SYNOPSISThe homogeneous grafting of acrylonitrile onto cellulose was carried out in a dimethyl sulfoxide/paraformaldehyde solvent system. The grafted products were added to cellulose/ polyacrylonitrile (PAN) blends as compatibilizers. The thermal decomposition behavior of the blends was investigated by thermogravimetry. The thermal stability of the blends with higher grafted product content was lower by more than 100°C than that of the blends without grafted product. The accessibility values of the former blends were larger than those of the latter. The microphase-separated structures of the grafted product blends were finer than those without the product. Dynamic mechanical measurements and differential scanning calorimetry were performed to estimate the glass transition temperatures, Tg, of the blends. The variation in Tg was smaller than that in characteristic temperatures determined by thermogravimetry. The difference in thermal decomposition behavior was correlated to that in compatibility. Thermogravimetry was found to be effective for estimating the compatibility in cellulose/PAN blends containing grafted products. 0

The homogeneous grafting of methyl methacrylate onto cellulose was carried out in a dimethyl sulfoxide (DMSO)/paraformaldehyde solvent system. The grafted products were added to cellulose/poly-(methyl methacrylate) (PMMA) blends as compatibilizers. The thermal decomposition behavior of the blends was investigated. The thermal stability of the blends with higher grafted product content was lower by more than 100 °C than that of the blends without grafted product. The values of accessibility for the former blends were larger than those of the latter and a cellulose sample cast from a DMSO solution. The microphase-separated structures of the former blends were finer than those of the latter. Dynamic mechanical measurements and differential scanning calorimetry were performed to estimate the glass transition temperatures (Te) of the blends. The variation in Tt was smaller than that in characteristic temperatures determined by the thermal decomposition measurement. The difference in thermal decomposition behavior was correlated to that in compatibility. Thermal decomposition measurements were effective for estimating the compatibility in cellulose/PMMA blends containing grafted products.* The viscoeity-average molecular weight (Mv) of backbone cellulose

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

ABSTRACT:Homogeneous grafting of 2-hydroxyethyl methacrylate onto cellulose was carried out in a dimethyl sulfoxidelparaformaldehyde solvent system. The grafted products were added to celluloselpoly(2-hydroxyethyl methacrylate) (PHEMA) blends as compatibilizers. The thermal decomposition behavior of the blends was investigated by thermogravimetry. The thermal stability of the blends decreased with an increase in grafted product content. Peak intensity of wide-angle X-ray diffraction patterns decreased with grafted product content. The microphase-separated structures of the blends became finer with grafted product content. Dynamic mechanical measurements were carried out to determine glass transition temperatures, T., of the blends. T• for cellulose decreased with grafted product content but that for PHEMA increased. Differences in thermal decomposition behavior of the blends were correlated to compatibility. Thermogravimetry was effective for compatibility estimation in celluloseiPHEMA blends containing grafted products.

ABSTRACT:The homogeneous grafting of methyl acrylate onto cellulose was carried out in a dimethyl sulfoxide/ paraformaldehyde solvent system. The grafted products were added to cellulose/poly(methyl acrylate) (PMA) blends as compatibilizers. The thermal decomposition behavior of the blends was investigated by thermogravimetry. The thermal stability of the blends decreased with an increase in grafted product content. Accessibility determined by a deuteration method increased with grafted product content and peak intensity of wide-angle X-ray diffraction patterns decreased. The microphase-separated structures of the blends with higher grafted product content were finer than those of the blends without grafted products. Dynamic mechanical measurements and differential scanning calorimetry were carried out to determine the glass transition temperatures, T 8 , of the blends. T, for cellulose decreased with an increase in grafted product content but that for PMA hardly varied. The difference in thermal decomposition behavior of the blends was correlated to that in compatibility. Thermogravimetry was effective for compatibility estimation in cellulose/PMA blends containing grafted products.KEY WORDS Thermal Decomposition / Cellulosic Blend / Grafted Product / Compatibilizer / We reported that the thermal decomposition behavior of the vinyl monomer grafted cellulose products depends remarkably on their graft copolymer contents. 1 • 2 In grafting, a graft copolymer and attendant homopolymer are synthesized simultaneously. 3 .4 Some of main chains not participating in grafting also remain. The grafted products thus are polymer blends containing graft copolymers as compatibilizers. The difference in thermal stability of the grafted cellulose products was correlated to compatibility. 1 • 2 The grafted products with different graft copolymer contents are necessary to correlate thermal stability with compatibility more precisely. In a series of our work, 5 • 6 the grafted products themselves were added to the cellulose/synthetic polymer blends as compatibilizers to vary graft copolymer content widely. In this work, methyl acrylate (MA) grafted cellulose products were added to cellulose/poly(methyl acrylate) (PMA) blends. EXPERIMENT AL Grafting and Sample PreparationHomogeneous grafting of MA onto cellulose in a dimethyl sulfoxide/paraformaldehyde (DMSO/PF) solvent system and characterization of the grafted products were performed by the method described previously. 7 -io The grafted products are characterized in Table I. In homogeneous grafting, the molecular weight of the graft polymer is presumed to be equal to that of the attendant homopolymer. 3 • 4 We confirmed that both molecular weights are consistent with each other within experimental error. 8 • 10 The viscosity-average molecular weights, Mv, of the extracted PMA thus were used as those of the graft polymers. The values of M" of cellulose and PMA used for the blends were estimated to be 146 x 10 3 and 290 x 10 3 from the intrinsic viscosities obtained with cadoxen 1...