Yasuo Sone

Radical Grafting from Carbon Black. Graft Polymerization of Vinyl Monomers Initiated by Peroxyester Groups Introduced onto Carbon Black Surface

AbstractCarbon blacks having tert-butyl peroxyester groups (1, 2, and 3) were prepared by the reaction of acyl chloride groups on carbon black with tert-butyl hydroperoxide. The introduction of acyl chloride groups onto carbon black was achieved by three methods: (1) reaction of a carboxyl group with thionyl chloride, (2) reaction of a phenolic hydroxyl group with adipoyl chloride, and (3) reaction of thionyl chloride with a carboxyl group introduced by the treatment of aromatic ring of carbon black with 4,4′-azobis(4-cyanovaleric acid). Carbon black 1 has no ability to initiate the graft polymerization of methyl methacrylate (MMA) because phenyl radical formed on the carbon black by decomposition of the peroxyester groups inhibited the polymerization. On the contrary, carbon blacks 2 and 3 were able to initiate the graft polymerization of MMA at 70–90°C and PMMA was effectively grafted onto the surface based on the propagation of the polymer from the alkyl radicals formed on the surface. The percentage of grafting of PMMA at 70°C by use of 3 as initiator increased to about 80% with progress of polymerization. Furthermore, the graft polymerization of several vinyl monomers initiated by 3 was investigated.

Graft Polymerization of Vinyl Monomers Onto Carbon Black by Use of the Redox System Consisting of Ceric Ions and Carbon Black Carrying Alcoholic Hydroxyl Groups

Abstract The radical graft polymerization of vinyl monomers onto carbon black initiated by a redox system consisting of ceric ion and carbon black having alcoholic hydroxyl groups was investigated. The introduction of alcoholic hydroxyl groups onto the carbon black surface was achieved by the reaction of carbon black with alcoholic hydroxyl radicals, formed by the reaction of alcohol with benzoyl peroxide. The rate of the polymerization of acrylamide (AAm) initiated by the redox system was found to increase in the following order of hydroxyl groups: 1-hydroxyoctyl < 1-hydroxypropyl < 1-hydroxyethyl < hydroxymethyl < 1-hydroxy-1-methylethyl. In the redox polymerization, poly-AAm was effectively grafted onto carbon black by propagation of the polymer from the radical formed by the reaction of ceric ions with the alcoholic hydroxy groups. The percentage of grafting increased with increasing conversion. By use of this redox system, poly(acrylic acid), polyacrylonitrile, and poly(N-vinyl-2-pyrrolidone) could b...

Carbon fiber as an initiator of cationic polymerization of N-vinylcarbazole

SummaryCarbon fibers were found capable of initiating the cationic polymerization of N-vinylcarbazole (NVC) at 60∼80°C. The activation energy of the polymerization was estimated to be 13.4 kcal/mol. The carbon fiber lost the initiating activity of the polymerization upon the blocking of carboxyl groups on the surface by the treatment with potassium bicarbonate or diazomethane. Therefore, it was concluded that carboxyl groups on carbon fiber play an important role in the initiation of the polymerization. Furthermore, it was found that during the polymerization, poly-NVC was grafted onto the surface; the grafting ratio was determined to be 39.7% (60°C, 24 h).

Cationic Grafting from Carbon Black. 4. Grafting of Poly(Oxytetramethylene) to Carbon Black by Ring-Opening Polymerization of Tetrahydrofuran Initiated by CO + ClO4- Groups on Carbon Black

Abstract It was found that the cationic ring-opening polymerization of tetrahydrofuran (THF) was initiated by carbon black containing CO+ClO4-groups, which had been introduced by the reaction of COCl groups with AgClO4, in the presence of promoters such as epichlorohydrin (ECH) and diketene. It was confirmed that formation of poly(oxytetramethylene), i.e., poly-THF, was propagated from CO+ClO4-groups on carbon black surfaces and effectively grafted onto it. The grafting ratio with ECH as promoter increased to 66.8% as conversion increased. The activation energy of the polymerization initiated by CO+ClO4- groups in the presence of ECH was determined to be 8.1 kcal/mol. Furthermore, poly-ECH, poly(styrene oxide), and poly(propylene oxide) can be grafted onto carbon black surfaces by the ring-opening polymerization of the corresponding alkylene oxides with CO+ClO4- groups on the carbon black as initiator. The polyether-grafted carbon black obtained from the above polymerization produced a stable colloidal di...

Grafting of polyesters from carbon fiber. Anionic ring-opening copolymerization of epoxides with cyclic acid anhydrides initiated by COOK groups on the surface of carbon fiber

Abstract To modify the surface of carbon fiber, the anionic grafting of polyesters from potassium carboxylate (COOK) groups on the surface was investigated. The COOK groups were introduced onto the surface of carbon fiber by the reaction of carboxyl groups (introduced by the oxidation of the surface with nitric acid) with potassium hydroxide. Untreated carbon fiber has no ability to initiate the anionic ring-opening copolymerization of epoxides with cyclic acid anhydrides. On the contrary, the anionic ring-opening copolymerization of epoxides—such as styrene oxide (SO), chloromethyloxirane (ECH), and glycidyl phenyl ether (GPE)—with cyclic acid anhydrides—such as maleic anhydride (MAn), succinic anhydride (SAn), and phthalic anhydride (PAn)—was found to be initiated by the COOK groups on the surface. In the polymerizations, alternating copolymers (i.e., polyesters) were effectively grafted from the carbon fiber surfaces depending on the propagation of the polymer from the surface COOK groups: for example,...

Anionic graft polymerization of vinyl monomers initiated by metallized aromatic rings of graphite powder

Anionic graft polymerizations of methyl methacrylate (MMA) and styrene from graphite powder initiated by metallized aromatic rings on the surface were investigated. Metalation of the surface was achieved by the reaction of polycondensed aromatic rings of graphite withn-butyllithium (BuLi) in N,N,N′,N′-tetramethylethylenediamine (TMEDA) or hexamethylphosphorous triamide (HMPT) at 0 °C., Anionic polymerizations of MMA and styrene were initiated by metallized graphite, and these polymers were grafted onto the surface. The conversion and percentage of grafting increased by increasing the amount of BuLi used for metalation. When 0.20 g of graphite was treated with 0.4–0.5 mmol of BuLi in TMEDA, the percentage of grafting of PMMA and polystyrene reached the maximum value: PMMA 52.8% (PMMA/graphite =0.528 g/1.0 g) and polystyrene 37.2% (polystyrene/graphite=0.372 g/1.0 g). Grafting of polymers was also confirmed by infrared spectra. Although no metalation of graphite proceeded in toluene, graphite could be metallized even in toluene by the addition of crown ether as a complexing cation agent. The stability of graphite powder in organic solvent dispersion was found to be improved remarkably by grafting of polymer onto the surface.

Cationic grafting from carbon black

SummaryThe cationic ring-opening copolymerization of tetrahydrofuran (THF) with a cyclic acid anhydride such as phthalic anhydride (PAn) and maleic anhydride was initiated by acylium perchlorate groups on carbon black to give alternating copolymer, i.e., polyester. Epichlorohydrin was found to act as effective promoter in the copolymerization. The polyester formed was effectively grafted from carbon black depending upon the propagation of the polymer from the surface: the grafting ratio of polyester from THF and PAn was increased up to about 65% with an increase in conversion. The polyester-grafted carbon black gave a stable colloidal dispersion in chloroform.

Reactive carbon black having isocyanate or acyl azide group

SummaryIntroduction of isocyanate (NCO) group onto carbon black surface was achieved by the treatment of carbon black with toluene-2,4-diisocyanate. In addition, carbon black having acyl azide (CON3) group, a precursor of NCO group, was prepared by the reaction of COCl or COOCOOC2H5 group on carbon black with NaN3. The CON3 group on carbon black was relatively stable at below 20°C but readily decomposed to NCO group by heating (Curtius rearrangement). By the reation of NCO group on carbon black with hydroxyl group of polymers, such as polypropylene glycol, polyethylene glycol, and polyvinyl alcohol, these polymers were found to be grafted onto carbon black.

Grafting Onto Carbon Black: Reaction of Functional Groups on Carbon Black with ACYL Chloride-Capped Polymers

Abstract The grafting of acyl chloride-capped polymers onto carbon black by the reaction of the acyl chloride group with the phenolic hydroxyl group on the surface was investigated. Acyl chloride-capped polymers were prepared by the reaction of functional polymers having terminal hydroxyl groups, such as poly(propylene glycol) (PPG), poly(ethylene glycol) (PEG), and silicone diol (SDO), with adipoyl dichloride or isophthaloyl dichloride. When acyl chloride-capped PPG (PPG-COCL) ([Mbar]n = 2.4 × 103) was reacted with carbon black, PPG was grafted onto the surface: the percentage of grafting reached to 27.7%. on the contrary, the reaction of PPG-COC1 with carbon black treated with diazomethane was scarcely observed. the PPG grafted onto carbon black was largely removed by hydrolysis with a dilute methanol solution of KOH. Based on these results, it was concluded that PPG grafted onto the surface with ester bonds. the percentage of grafting increased with an increase in the molecular weight of PPG-COC1. in a...

Cationic Polymerization of N-Vinylcarbazole and N-Vinyl-2-Pyrrolidone Initiated by Carboxyl Groups on Carbon Fibers

Abstract The effects of solvent and temperature on the grafting of poly(N-vinylcarbazole) (NVC) onto carbon fiber by cationic polymerization initiated by carboxyl groups on the surface were investigated in order to obtain poly-NVC-grafted carbon fiber with a higher percentage of grafting It was found that the rate of the polymerization of NVC increased, depending on the dielectric constant of the solvent, in the following order: toluene < 1,2-dichloroethane < nitrobenzene. However, the percentage of grafting of poly-NVC onto the carbon fiber obtained from polymerization in nitrobenzene was smaller than that in toluene. This may be due to differences in the chain transfer of the growing polymer cation to NVC and these solvents. Furthermore, poly-NVC-grafted carbon fiber with a higher percentage of grafting was formed at a lower polymerization temperature, i.e., 60°C. In addition, it became apparent that carbon fiber is capable of initiating the cationic polymerization of N-vinyl-2-pyrrolidone (NVPD), and p...