Statistical radii of gyration, second virial coefficients, and intrinsic viscosities of sharp fractions (M̄w/M̄n ≈ 1.1) of polyisobutylene (PIB) covering a wide range of molecular weight (1.6 × 105 to 4.7 × 106) were determined in isoamyl isovalerate (IAIV) at a number of temperatures ranging from 20 to 60°C, in n‐heptane at 25°C, and in cyclohexane at 25°C by light‐scattering and viscosity measurements. It was found that IAIV at 22.1°C is a theta solvent for PIB. Analysis of the data by the methods described in preceding papers of this series indicated that, except for minor differences, the conclusions derived from similar studies with polychloroprene, polystyrene, and poly‐p‐methylstyrene hold equally for solutions of the typical linear polymer investigated here. In particular, no decisive evidence for the drainage effect was found.

Polystyrene particles incorporating poly(methylphenylsilane) (PMPS) were synthesized by miniemulsion polymerization. UV irradiation of the emulsion under air in the presence of metal salts such as HAuCl4.4H2O, AgNO3, and Na2PdCl4 led to the formation of metal nanoparticles on the surface of polymer particles; thus, metal nanoparticle/polymer hybrid particles were obtained. The structures of the hybrid particles were confirmed by the surface plasmon resonance band and transmission electron microscopy images. The formation of metal nanoparticles depended on the functional groups and charge on the surface of the polymer particle. The metal nanoparticles were formed due to the reduction of metal ions, accompanied by the oxidation of PMPS. The interaction between the surface of the polymer particle and the metal ions plays an important role in the formation of the metal nanoparticle.

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.

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

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