摘要:

Radical copolymerizability of 6-methyl-2-vinyl-3-pyridazinone (I) has been reinvestigated in acetic acid and also in the presence of polyacrylic acid (PAA). Copolymerization of styrene with I was carried out in a few solvents. A positive e2value was obtained in acetic acid while negative ez values were obtained in benzene and DMF. I was allowed to copolymerize with a few monomers such as styrene, methyl methacrylate, and acrolein in the presence of PAA to give block-type copolymers. All these observations indicate that polymerizability of I is controlled by the hydrogen bonding interaction between the carbonyl group of I and the hydroxyl group of the additive.

ISSN:0022-233X    

DOI:10.1080/00222338108074376

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The initiation mechanism for spontaneous copolymerizations of vinyl sulfides (VS) with electron-accepting monomers such as maleic anhydride (MAn), diethyl fumarate (DEF), acrylonitrile (AN), and methyl acrylate (MA) was investigated by means of spin trapping technique using 2-methyl-2-nitrosopropane as a spin trapping agent. From the ESR spectrum observed from the system ethyl VS-DEF, two types of radicals, a vinyl radical (I; RSCH=CH) and an alkyl (1, 2-dicarboethoxyethyl) radical (II; C2H5OCOCHCH2COOC2H5) which derived from VS and DEF, respectively, were detected as their nitroxides. Similar radicals, I and III (NCCH2CH2), were also observed from the system VS-AN, but in the system VS-MA, three types of radicals, I, IV (CH3OCOCH2CH2), and V (CH3OCOCHCH3) were trapped as their nitroxides. In the system isopropyl VS-MAn, I and a propagating radical (VI) ∼∼CH2CHSR, were detected. The system isobutyl vinyl ether-MAn also showed a weak ESR spectrum due to the nitroxide from Radical I. These initiating radicals were assumed to be produced from the charge transfer complex formed between both donor and acceptor monomers. Based on these results, the cross-initiation mechanism for spontaneous alternating copolymerization is discussed.

ISSN:0022-233X    

DOI:10.1080/00222338108074377

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Aromatic polyesters containing peroxide groups incorporated in the polymer chains were synthesized by interfacial polycon-densation of bisphenol A, sodium peroxide, and isophthaloyl chloride. Iodometric titration, elemental analysis, and IR spectra showed that the polymers obtained possessed a high peroxide content, even though bisphenol A reacted 80 times faster than Na2O2with isophthaloyl chloride. Analysis of the polymers by high resolution NMR and degradation of the chains with subsequent gel permeation chromatography measurements showed that the distribution of peroxide groups is random in the case of low peroxide content. Higher peroxide content leads to the formation of peroxide blocks in the polymer as well as greater polydispersity of the polyester fragments formed after degradation of the peroxide links.

ISSN:0022-233X    

DOI:10.1080/00222338108074378

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The usual copolymerization equation obtained for the terminal charge transfer model by Seiner and Litt is discussed. A new definition, valuable especially for K-values higher than 0.03 and for systems having low probabilities of the homopropagation reactions, is proposed for the reactivity ratios. The higher generality of the new equation is demonstrated on two systems. Two FORTRAN programs for nonlinear estimation with least-square error of the parameters are presented and discussed.

ISSN:0022-233X    

DOI:10.1080/00222338108074379

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Radical copolymerization of N-(2-hydroxyethyl)carbazolyl acry-late with picryl methacrylate takes place mainly through the inter-monomeric charge transfer complex (CTC) in dioxane solution. When the solvent is 1, 2-dichloroethane, concurrent chain transfer reactions arise. The copolymers obtained are intramolecular CTC. The charge transfer interaction depends on copolymer composition and conformation, and on the copolymerization solvent.

ISSN:0022-233X    

DOI:10.1080/00222338108074380

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The photopolymerization of triallylidene sorbitol (TAS) was carried out in benzene at 40°C without the usual initiator. The polymerization of TAS was found to be initiated with the ester radical generated via the acetal radical from TAS by means of photoirradiation. The rate of polymerization and the molecular weight of polymer were small due to the degradative chain transfer, It was kinetically investigated from the standpoints of the degradative chain transfer by the allylidene group and the cyclization by three double bonds. The following results were obtained: (1) The relation between the rate of polymerization, Rp, the monomer concentration, [M], could be expressed by [M] /Rp= (A[M] + B)/(3[M] + C), where A, B, and C were constant; (2) the ratio of the rate constant of unimolecular cyclization to the total rate constant of bimolecular propagation and the chain transfer of uncyclized radical was estimated to be 3.0 mol/dm3. A small amount of cyclopolymerization took place.

ISSN:0022-233X    

DOI:10.1080/00222338108074381

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Polychelates of VO(II), Mn(II), Zn(II), Cr(III), and Fe(III) with the bis-oxime of 5, 5′-methylene-bis-salicylaldehyde have been prepared and are characterized on the basis of their elemental analyses, IR, diffuse reflectance spectra, magnetic moments, and thermogravimetric analyses. Except for VO(II), the other metal ions form octahedral polychelates. VO(II) forms a square-pyramidal coordination polymer. The Zn(II) poly-chelate has the highest thermal stability.

ISSN:0022-233X    

DOI:10.1080/00222338108074382

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Cu(II), Ni(II), and Co(II) chelate polymers were prepared from Schiff base of 5, 5′-methylene-bis-salicylaldehyde with aniline. All the polymers are amorphous and insoluble in common organic solvents. They are characterized on the basis of conductivity, infrared, and electronic spectral properties in conjunction with magnetic susceptibility measurements. Various ligand field and nephelauxetic parameters have been evaluated for Ni(II) and Co(II) polychelates. They are consistent with octahedral structure for the former and tetrahedral structure for the latter. Their thermogravimetric analysis show the Co(II) > Ni(II) > Cu(II) order of thermal stability. Kinetic parameters were also obtained.

ISSN:0022-233X    

DOI:10.1080/00222338108074383

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The most usual procedure to estimate the chain transfer ratio in vinyl polymerization is to use a Mayo plot. This plot can only be applied directly when the polymerization rate is not modified by the chain transfer agent. In spite of this, the equation has been applied to several systems where this condition is not fulfilled. In the present work we present a slightly modified equation that can be employed irrespective of the changes in rate. This equation is applied to several systems reported in the literature. The improvement in the interpretation of the results in these systems is discussed.

ISSN:0022-233X    

DOI:10.1080/00222338108074384

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Poly(methyl acrylate) has been graft copolymerized onto a soluble protein, gelatin, in aqueous medium by using eerie amnionic nitrate (CAN) as the redox initiator. Graft copolymerization was carried out at 35, 45, and 55°C for various reaction periods. Maximum percent grafting occurred at 45°C. Nitric acid was found to influence grafting. Percent grafting has been determined as a function of (1) concentration of CAN, monomer, and nitric acid; (2) time; and (3) temperature.

ISSN:0022-233X    

DOI:10.1080/00222338108074385

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor