摘要:

The copolymerizations of N-acryloyl pyrrolidone (NAP) with vinyl monomers methyl methacrylate (MMA), acrylonitrile (AN) and acrylamide (AA) were carried out in dimethylformamide at 65°C using 2,2′-azobisisobutyronitrile(AIBN) as an initiator. The resulting copolymers were used as a polymeric initiator of the anionic graft copolymerization of 2-pyrrolidone. The percent grafting of 2-pyrrolidone onto vinyl copolymer backbone chain involving N-acyllactam groups was found best with copoly(NAP-co-MMA) when the KOH concentration was 0.03M. The presence of crown ether increased the viscosity of graft copolymers and accelerated the initial rate of anionic graft copolymerization.

ISSN:0022-233X    

DOI:10.1080/00222338208074428

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A phenolic copolymer has been prepared by copolymerization of p-chlorophenol, p-cresol, and formaldehyde in the presence of acid catalyst. The copolymer was partially and completely dehalogenated by a standard method. The dehalogenated copolymer chain had a random distribution of reactive positions which were originally occupied by Cl atoms. Some substituted monomers, oligomers of known structure and molecular weight, and basic polymer chains have been grafted at these reactive positions. The halogen percentage of the grafted copolymers could be calculated on the assumption that all the available reactive positions are attached to the respective units. Reasonably good agreement has been found between the calculated and observed amount of halogen percentage in the grafted copolymers.

ISSN:0022-233X    

DOI:10.1080/00222338208074429

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The polymerization of methyl methacrylate was studied using Mn(acac)3, Co(acac)3, and Fe(acac)3complexes. The rate of polymerization at various complex and monomer concentrations were investigated and it was observed that the plots of Rpversus [M]2and Rpversus 1/[complex] were linear. The reactions were studied at different temperatures and the overall activation energies were computed to be 4.70, 5.50, and 6.40 kcal/mol for Mn3+, Co3+, and Fe3+complexes, respectively. The effect of inhibitor on the polymerization rate was studied. Using the well-known Tüdös equation, the Tüdös inhibitor constant was computed to be 10. A suitable kinetic scheme for the polymerization has been pictured.

ISSN:0022-233X    

DOI:10.1080/00222338208074430

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Factors affecting the stability of three kinds of cellulose peroxides prepared by reactions of aldehyde cellulose, carboxy-methyl cellulose, and unmodified cellulose with hydrogen peroxide, Peroxides A, B, and C, respectively, were investigated. The relative stability of the peroxides was in the order Peroxide A > B > C, which was greatly improved by applying ethylenediaminetetraacetic acid as the chelating reagent for the metals in a very small amount in the sample. The sample kept under nitrogen retained stable activity of the peroxide longer than that under air atmosphere. Water in the sample seemed to participate in the decomposition of the peroxide to some extent. The functions of metals, water, and atmosphere on the decomposition of peroxide are discussed.

ISSN:0022-233X    

DOI:10.1080/00222338208074431

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Recent information on the use of transition metal chelates as initiators of free radical polymerization of vinyl monomers is supplied. Chelates of various kinds and of various coordination numbers, derived from transition metal ions such as Mn(II), Mn(III), Co(II), Co(III), Fe(II), Fe(III), Cu(I), and Cu(II) with a multitude of both monomeric and polymeric ligands, are taken into consideration. The efficiency of the individual chelates toward radical polymerization of vinyl monomers under variable reaction conditions are discussed. The co-catalytic activity of some chelates in photopolymerization and peroxide initiated vinyl polymerization is accounted for. The kinetic results and spectroscopic evidence leading to the mechanistic details of individual paths of initiation of polymerization are discussed.

ISSN:0022-233X    

DOI:10.1080/00222338208074432

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Aqueous polymerization of methyl methacrylate (MMA) initiated by potassium persulfate-thioglycollic acid (TGA) redox system has been studied at 30°C under nitrogen atmosphere. The rate of polymerization is expressed byThe polymerization was studied over the temperature range 20–45°C. The activation energy calculated from an Arrhenius plot was found to be 8.34 kcal/mol (34.9 kJ/mol). The effects of inorganic electrolytes and organic solvents on polymerization were also investigated. Except for manganese sulfate and sodium oxalate, all of them depressed both the initial rate and the limiting conversion.

ISSN:0022-233X    

DOI:10.1080/00222338208074433

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Ring-scission polymerization of 6,6′-bis[3, 1-benzoxazin-2,4-dione] was studied in presence of such catalysts as aqueous HC1, benzidine-3,3′-dicarboxamide, N-methyl aniline, o-chloroaniline, benzidine-3,3′-dicarboxylic acid, and acid amides under various experimental conditions. It was found that 6,6′-bis[3,1-benzoxazin-2,4-dione] undergoes ring-scission polymerization, affording polyanthranilides in the presence of the first five catalysts under appropriate experimental conditions. The samples are insoluble in all organic solvents including formic acid. They are soluble in sulfuric acid with degradation. They are characterized by IR spectral and thermogravimetric analysis.

ISSN:0022-233X    

DOI:10.1080/00222338208074434

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Ultrasonic (70 W, 20 kHz) degradations of polystyrene (PS) have been carried out with various poly(alkyl methacrylates) (PRMA) for periods of 3 h at 27°C in toluene (2.0 to 5.0% solutions). The isolation of sequence copolymers thus prepared from their associated homopolymers was achieved by employing selective solvents (solvent for one homopolymer but a precipitant for the second homopolymer in the mixture). The recovered products were analyzed by gel permeation chromatography (GPC), infrared spectroscopy (IR), and viscometry. These analyses showed that when the substituents in PRMA were methyl, ethyl, isopropyl, n-butyl, isobutyl, or phenyl, sequence copolymers with segments from PS as well as from poly(alkyl methacrylate) were obtained. However, when the substituents on PRMA were hexyl, isodecyl, lauryl, hexadecyl, octadecyl or isobornyl there were no sequence copolymers formed. The decrease in the intrinsic viscosity of the recovered homopolymers and shifts of their GPC chromatograms toward the low molecular weight end suggest that on sonification PRMA samples having bulkier substituents do degrade and yield radicals which, however, do not recombine with those from polystyrene. Furthermore, ultrasonic degradation of polystyrene is found to be dependent on the chain stiffness of the poly(alkyl methacrylates).

ISSN:0022-233X    

DOI:10.1080/00222338208074435

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Anionic polymerization of methyl methacrylate (MMA) was initiated with the disodium salt of dihydroxy-poly(tetra-methylene oxide) (PTMO) in tetrahydrofuran in the presence and the absence of a crown ether. The resulting block copolymer of poly(methyl methacrylate) (PMMA) and PTMO was characterized by1H NMR spectroscopy, gel permeation chromatography, and solvent extractions. In the absence of the crown ether, a linear triblock copolymer of PMMA-PTMO-PMMA was predominantly obtained, showing a unimodal and relatively narrow molecular weight distribution. In the presence of the crown ether, a linear triblock copolymer and a PTMO grafted block copolymer due to the transesterification reaction between PTMO and a methoxy group in MMA were produced with an increase in polymer yield. The stereosequence distributions of the PMMA part in the copolymers were essentially atactic and the addition of the crown ether increased the fraction of the rr triad.

ISSN:0022-233X    

DOI:10.1080/00222338208074436

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Poly[2,2′-(R-substituted-o-phenylene)-5,5′bibenzimidazole]s [R = m-NHad), m-NHAC (II), p-Cl (III), and the N-methylation products of II and HI and the chlorination product of poly[2,2′-(o-phenylene)-5,5′-bibenzimidazole] (IV)] are prepared and characterized by their IR spectral study and thermal analysis. Model compounds, 2,2′-di(R′-phenyl)-5,5′-bibenzimidazoles [R′ = O-NH2(Im), o-NHAc (Em), and m-chloro (Mm)] are prepared for comparison of their properties with those of the polymer samples I, II, and III, respectively.

ISSN:0022-233X    

DOI:10.1080/00222338208074437

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor