Sachio Yoshikawa

Polymer grafting onto carbon black by use of TEMPO‐terminated polystyrene with controlled molecular weight

The grafting of polystyrene with controlled molecular weight and narrow molecular weight distribution onto the carbon black surface through the trapping of polymer radicals formed by the thermal dissociation of 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO)-terminated polystyrene (PSt-TEMPO) by the carbon black surface was investigated. PSt-TEMPO was prepared by living radical polymerization of St with the benzoyl peroxide/TEMPO system. When PSt having no terminal TEMPO moiety was heated with carbon black, no grafting of PSt onto the surface was observed. On the contrary, by the heating of PSt-TEMPO with carbon black in m-xylene at 125°C, PSt with controlled molecular weight and narrow molecular weight distribution was grafted onto the surface: the percentage grafting of PSt (Mn = 3.2 × 103;Mw/Mn = 1.07) onto furnace black was determined to be 16.0%. On the basis of the above results, it is concluded that PSt radicals formed by the thermal dissociation of the CON bond between PSt and TEMPO are trapped by polycondensed aromatic rings of carbon black. The mole number of grafted PSt chains on the carbon black surface decreased with increasing molecular weight of PSt-TEMPO. PSt-grafted carbon black gave a stable colloidal dispersion in THF.

Grafting reaction of living polymer cations with amino groups on chitosan powder

The grafting of polymers having controlled molecular weight and narrow molecular weight distribution onto chitosan powder by the termination of living polymer cation with amino groups on chitosan powder was investigated in heterogeneous system. The amino groups of chitosan powder successfully reacted with living poly( isobutyl vinyl ether) [poly(IBVE)] and poly(2-methyl-2-oxazoline) [poly(MeOZO)] cation with controlled molecular weight and narrow molecular weight distribution to give the corresponding polymer-grafted chitosan powders. The percentage of poly( MeOZO) grafting gradually increased and reached 24.5% after 4 days. The solubility of poly(MeOZO)-grafted chitosan in water increased with an increase in the amount of grafted polymer. It was suggested that grafting reaction of living polymer cation with chitosan powder proceeds from surface amino groups to inner amino groups of the powder with progress of the reaction. The mole number of grafted polymer chain on chitosan powder decreased with an increase in the molecular weight of the living polymer cation because the steric hindrance of functional groups of chitosan powder increased with the increasing molecular weight of living polymer.

Post-grafting of polymer with controlled molecular weight onto silica surface by termination of living polymer cation with terminal amino groups of dendrimer-grafted ultrafine silica

Abstract To modify the surface of ultrafine silica, the grafting reaction of living polymer cation with dendrimer-grafted silica having terminal amino groups was investigated. The polyamidoamine dendrimer-grafted silica having terminal amino groups was readily reacted with living poly(isobutyl vinyl ether) (polyIBVE), which was synthesized by cationic living polymerization with a HCl/ZnCl 2 initiating system, and polyIBVE with controlled molecular weight and narrow molecular weight distribution was post-grafted to the dendrimer-grafted silica surface. By the termination of living poly(2-methyl-2-oxazoline) (polyMeOZO), which was synthesized by cationic ring-opening polymerization with methyl p -toluenesulfonate initiator, with terminal amino groups of polyamidoamine dendrimer-grafted silica, polyMeOZO was also post-grafted to the surface of polyamidoamine dendrimer-grafted silica; the percentage of overall grafting of polyMeOZO was determined to be 361.6% based on silica.

Grafting of living polymer cations with organic pigments

Abstract To modify the surface of organic pigments such as 5,12-dihydoroquino[2,3-β]acridine-7,14-dione (quinacridone, QD), 3,6-di (p-chlorophenyl)-1,4-diketo-pyrrolo[3,4-c]pyrrole (diketo-pyrrolopyrrole: DPP), and 1,1′-bi(9,10-anthracene-dione)-4,4′-diamine (anthraquinone: AQ), the grafting of polymers with these organic pigments at the amino groups was investigated. The amino groups of QD, DPP, and AQ readily reacted with living poly(isobutyl vinyl ether) (poly(IBVE)) cation with controlled molecular weight and narrow molecular weight distribution. Grafting of living poly(2-methyl-2-oxazoline) (poly(MeOZO)) cation onto these organic pigments was also performed. The mole number of the grafted polymer chain on the organic pigment surface decreased with increasing molecular weight of the living polymer, because the steric hindrance of the organic pigment surface increased with increasing molecular weight of living polymer. By grafting of poly(IBVE) onto the QD surface, the wettability of the surface drastically changed from hydrophilic to hydrophobic.

Surface grafting of hyperbranched dendritic polymer onto glass fiber

This paper describes surface grafting of hyperbranched dendritic polyamidoamine, a new class of topological macromolecules, onto glass fiber for modification of the glass fiber surface. Glass fiber having surface amino groups as initiator sites was prepared by treatment of the glass fiber with 3-aminopropyltriethoxysilane. Grafting reaction of the hyperbranched dendritic polyamidoamine from the glass fiber surface was achieved by repeating Michael addition of methyl acrylate to surface amino groups followed by amination of end groups, which is the reaction of the resulting ester moieties with ethylenediamine or hexamethylenediamine. Both the amount of terminal amino groups and the percentage of grafting of the resulting polyamidoamine increased with an increase in the number of generations. Ethylenediamine as a reactant in amination was more effective than hexamethylenediamine for the propagation of the hyperbranched dendritic polyamidoamine. However, the propagation of the polyamidoamine from glass fiber...

Grafting of polymers with controlled molecular weight onto inorganic fiber surface by termination of living polymer cation with amino group on the surface

To modify the surface of inorganic fibers such as glass fiber (GF), alumina fiber (A1F), and carbon fiber (GF), we investigated the grafting of polymers by termination of living polymer cation with amino groups introduced onto the fiber surface. The introduction of amino and N-phenylamino groups onto GF and AIF were achieved by the treatment of fiber surface with γ-aminopropyltrietoxysilane and N-phenyl-γ-aminopropyltrimethoxysilane, respectively. The introduction of amino groups onto CF was performed by the reduction of nitrated CF. These amino groups on inorganic fiber surface readily reacted with living poly(isobulyl vinyl ether) (poly(IBVE)) cation, and poly(IBVE) with controlled molecular weight and narrow molecular weight distribution was grafted onto the surface. By the termination of living poly(2-methyl-2-oxazoline) (poly(MeOZO)) cation with amino groups on inorganic fiber, poly(MeOZO) was also grafted onto the surface. The mole number of grafted polymer chain on inorganic fiber surface decreased...

Living-like cationic polymerization of isobutyl vinyl ether initiated by carboxyl groups of solid surface in the presence of zinc chloride

We investigate the effects of Zn Cl 2 as catalyst on the cationic polymerization of isobutyl vinyl ether (IBVE) initiated by carboxyl groups introduced onto crosslinked polstyrene bead surface and those on poly(acrylic acid-co-divinylbenzene) cation exchange resin surface as model compounds of carbon black. In addition, the grafting reactions of poly(IBVE) with controlled molecular weight and narrow MWD onto polystyrene bead and cation exchange resin after the quenching of the polymerization with methanol were discussed

“LIVING-LIKE” CATIONIC POLYMERIZATION OF ISOBUTYL VINYL ETHER INITIATED BY CARBOXYL GROUPS ON CARBON BLACK SURFACE/ETHYLALUMINUM DICHLORIDE SYSTEM IN THE PRESENCE OF 1,4-DIOXANE

The effect of 1,4-dioxane as an added base on the cationic polymerization of isobutyl vinyl ether (IBVE) initiated by carboxyl groups on carbon black surface/ethylaluminum dichloride (EtAlCl2) system was investigated. Although the cationic polymerization of IBVE by carbon black/EtAlCl2 system the absence of 1,4-dioxane instaneously proceeded and the monomer conversion achieved 100% within a minute. The molecular weight distribution (MWD) of polyIBVE obtained was very broad. On the contrary, the MWD of polyIBVE obtained was very narrow and narrower than that obtained from the carbon black/ZnCl2 initiating system by the addition of 1,4-dioxane. The number-average molecular weight (Mn) of polyIBVE obtained was directly proportional to monomer conversion in the cationic polymerization. However, the Mn of polyIBVE obtained from the polymerization by the initiating system in the the presence of 1,4-dioxane was smaller than that of the calculated value, assuming that polyl(IBVE) chain forms per unit carboxyl group on carbon black surface. It was concluded that carbon black/EtAlCl2 initiating systems in the presence of 1,4-dioxane has an ability to initiate “living-like” cationic polymerization of IBVE based on the above results. PolyIBVE was grafted onto a carbon black surface after quenching the above “living-like” cationic polymerization systems with methanol.

Composite of synthetic mica with polymers: grafting of polymers with controlled molecular weight onto synthetic mica by use of living polymer cation

The grafting of polymers onto synthetic mica surface and formation of an interlayer by the termination of living polymer cation with amino groups introduced onto the synthetic mica was investigated. The introduction of amino groups onto the synthetic mica was achieved by the reaction of silanol groups with γ-aminopropyltriethoxysilane. It was found that living poly(isobutyl vinyl ether) (polyIBVE) and living poly(2-methyl-2-oxazoline) (polyMeOZO) cations with controlled molecular weight and narrow molecular weight distribution were successfully terminated by amino groups of synthetic mica, and the corresponding polymers were grafted onto the surface and interlayer of the mica. The grafting of polyIBVE and polyMeOZO on the synthetic mica decreased with increasing molecular weight of the living polymer cations. The effect of reaction temperature on the grafting of polyMeOZO onto the synthetic mica was examined. The X-ray diffraction curves of polyMeOZO-grafted synthetic mica have a peak at 2 = 4.5° assigned 001 lattice spacing: the lattice spacing was expanded by the grafting of polyMeOZO in the interlayer of the synthetic mica.