Polymer Journal

Kamida, Kenji; Okajima, Kunihiko; Matsui, Toshihiko; Kowsaka, Keisuke

doi: 10.1295/polymj.16.857pmid: N/A

A correlation of the solubility of cellulose in aqueous alkali solution was established with its so-called “amorphous” content. To achieve this end, cellulose was regenerated under different preparative conditions from its cuprammonium solution and cotton linter was acid-hydrolyzed into a fibrous form and the pulp was physically milled to powder. Cellulose having a relatively large molecular weight was found to completely dissolve in aqueous NaOH solution at 4°C. The solubility of cellulose in a 10 wt% aqueous NaOH at 4°C, S a could generally be correlated to the relative amount of the high magnetic field envelope of the C4 carbon NMR peak, χh (NMR). χh (NMR) was assigned to the region where intramolecular hydrogen bonds are at least partly broken. The intramolecular hydrogen bond was found to have an important influence on the solubility behavior of cellulose.

Nishioka, Noboru; Watase, Keiji; Arimura, Keiji; Kosai, Kouichi; Uno, Masakuni

doi: 10.1295/polymj.16.867pmid: N/A

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.

Nishioka, Noboru; Yoshimi, Seiichiro; Iwaguchi, Tatsuya; Kosai, Kouichi

doi: 10.1295/polymj.16.877pmid: N/A

Differential scanning calorimetry was used to investigate the states of water in cellulose membranes grafted with acrylonitrile (AN). Examination of the melting endotherms and freezing exotherms showed the existence of three water states differing in their interaction with polymer molecules: free water, intermediate water, and bound water. The amount of intermediate water was remarkably reduced by grafting AN onto cellulose. The amounts of freezing water and nonfreezing water were estimated to elucidate the diffusive permeability of solutes through the membranes. The difference in permeability through the membranes may be explained by the difference in freezing water content. The intermediate water may not be appreciably related to the permeation of solutes through the membranes.

Horie, Kazuyuki; Takagi, Toshie; Mita, Itaru; Shindo, Yoichi; Sato, Hisaya; Tanaka, Yasuyuki

doi: 10.1295/polymj.16.887pmid: N/A

Rate constants of quenching, k q, and hydrogen abstraction, k a, of benzophenone triplet with oligostyrenes from dimer to hexamer as well as with cumene were determined in acetonitrile at 30°C from transient phosphorescence decay and quantum yield for benzophenone reduction measurements. The values of k q=(4.0±1.0)×106 unit-M−1s−1 and k a=(1.3±0.3)×105 unit-M−1s−1 for oligostyrenes are independent of the number of monomer unit, n. The k q for oligostyrene is three times larger than k q for cumene, its monomer model, supposingly due to a sandwich-type encounter of benzophenone with two adjacent phenyl groups, but k a for oligostyrene is equal to k a for cumene. The chemical reaction (hydrogen abstraction) contributes in only 3.5% to total deactivation of benzophenone triplet by oligostyrenes.

Zhu, Shan-Nong; Asakura, Tetsuo; Chûjô, Riichirô

doi: 10.1295/polymj.16.895pmid: N/A

The conformational probabilities for highly isotactic polypropylene involving various types of stereodefects were calculated. They are effected not only by the dyad in which the defects are present but also by that in neighboring sites. By taking the γ effect and conformational probabilities into account, chemical shift differences were calculated for methyl and methine carbons. From the chemical shift calculations, assignments due to stereodefects were performed for all peaks observed in both methyl and methine carbon resonance regions of the polypropylene spectrum.

Kodaira, Toshiyuki; Tsuji, Sumio; Okuyama, Kiyomi; Hosoki, Yukiomi

doi: 10.1295/polymj.16.901pmid: N/A

The polymerization behavior of N,N′-dimethacryloylmethylhydrazine (DMUM) was investigated. The two methacryloyl groups in DMUM have essentially different reactivities; one, attached to the nitrogen with a methyl group, definitely has a lower polymerizability than the other. Cyclopolymerizability of DMUM is explained by taking into account the difference in the reactivities of the two methacryloyl groups. Solvent effects on the cyclopolymerizations of DMUM and sym-dimethacryloyldimethylhydrazine (DMMH) have also been studied in connection with the hydrogen-bonding ability of DMUM. Solvents influenced not only the polymerization rate of DMUM but also the structure of the resulting poly-DMUM to a small extent. However, the polymerization of DMMH is not affected by solvents. These results and spectroscopic studies on the molecular interaction in solution have led to the conclusion that molecular association through hydrogen-bonding is responsible for the solvent effects observed.

Tanisugi, Hideaki; Kotaka, Tadao

doi: 10.1295/polymj.16.909pmid: N/A

The pervaporation of water and ethanol at 25°C was examined on as-cast and annealed membranes of (AB)n-type multiblock copolymers of bisphenol-A polycarbonate (PC) and polyoxyethylene (POE) of varying composition and block length. The equilibrium degree of swelling, q e (in g liquid/100 g dry membrane), for water decreases rapidly with increasing PC content of the samples, while that for ethanol remains nearly constant. The pervaporation rate P of water also decreases with increasing PC content, while that of ethanol is high for samples with 30 and 75 wt% PC content, but low for those with 50 wt% PC content. Swelling and pervaporation of as-cast specimens of these block copolymers appear to be complicated by the incomplete microphase separation between the components. Nevertheless, except for a few cases, annealing the membranes at 60°C appears to cause their microdomain structures to be more like those of equilibrium morphology so that their pervaporation behavior becomes like that expected from simple additivity with respect to the volume fraction of the phases. Our results suggest that the pervaporation of water through these copolymers is governed essentially by solubility, but that of ethanol, by diffusivity.

Shimidzu, Takeo; Iyoda, Tomokazu

doi: 10.1295/polymj.16.919pmid: N/A

A thin and flexible sandwich-type photocell with visible-light illumination is presented. The photocell is prepared by a dye-containing polymer coating on a semiconductor-deposited film-type electrode. The advantages in applying a polymer coated electrode to a visible-light-induced photocell with high efficiency are pointed out.

Kitayama, Tatsuki; Ute, Koichi; Hatada, Koichi

doi: 10.1295/polymj.16.925pmid: N/A