摘要:

The ring-opening polymerization of 1-benzylazetidine (BA) was investigated in bulk and in acetonitrile. The bulk polymerization of BA proceeded with cationic initiators, such as methyl tosylate and 3-hydroxy-1-propanesulfonic acid sultone (PS), at 60°C, and a white, powdery polymer was obtained. The polymer structure was confirmed by elemental analysis and NMR spectroscopy. The polymerization of BA with PS was assumed to proceed via a zwitterion formed by the addition reaction of BA and PS. The polymerization rate was studied in acetonitrile as a solvent. The enthalpy of activation ΔH* and the entropy of activation ΔS* for the propagation were determined.

ISSN:0022-233X    

DOI:10.1080/00222338608063393

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The aqueous polymerization of acrylamide initiated by the potassium persulfate/lactic acid system catalyzed by Ag+ions has been studied iodometrically over the temperature range from 35 to 50 ± 0.2°C. The rate of polymerization is governed by the expression Rp∞ [M]0.8[K2S2O8]1.0[Ag]1.0The deviation from normal kinetics has been studied. A tentative mechanism of initiation is suggested. The overall energy of activation is 5.52 kcal/mol.

ISSN:0022-233X    

DOI:10.1080/00222338608063394

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Synthesis of water-insoluble poly(o-N-acryloylaminobenzoic acid) was investigated by free radical polymerization. Kinetics of polymerization of o-N-acryloylaminobenzoic acid (OAB) initiated by 2,2′-azoisobutyronitrile (AIBN) in dioxane was studied at 78–100°C. The rate of polymerization was evaluated by varying the concentration of monomer and initiator. The rate of polymerization was found to increase steadily with increasing monomer concentration. The overall activation energy was found to be 9.8 kcal/ mol. A suitable kinetic scheme is proposed, and a rate equation has been derived.

ISSN:0022-233X    

DOI:10.1080/00222338608063395

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Light scattering and viscosity studies were made on dilute solutions of poly(vinyl chloride) (PVC) in three solvents: cyclo-hexanone, cyclopentanone, and tetrahydrofuran. Eight samples of PVC (Mw= 25,400 to 145,000) were used to determine the intrinsic viscosities, molecular weights, and the polymer-solvent interaction parameters over a range of temperatures. The solutions were found to behave normally and to exhibit no evidence of aggregate formation. The molecular weights obtained in all three solvents were independent of temperature and agreed well within the experimental errors. The interaction parameters observed were independent of concentration and molecular weight, and functions only of temperature. The intrinsic viscosities were related to molecular weight by the Mark-Houwink equation between 20 and 50°C. The temperature coefficient of the interaction parameter obtained by light scattering agrees well with that found by viscometry. Cyclohexanone, cyclopentanone, and tetrahydrofuran are all good solvents for PVC, and the order of solvent quality is cyclohexanone > cyclopentanone > tetrahydrofuran.

ISSN:0022-233X    

DOI:10.1080/00222338608063396

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Thermal behavior of saponified products of an acrylic terpolymer was studied by differential scanning calorimetry and thermogravimetry in a nitrogen atmosphere. The exothermic reaction was attributed to the oligomerization of nitrile groups by comparing the extent of the reaction with the number of nitrile groups present. A shift in the position of the exotherm was observed with an increase in the degree of saponification up to 0.730, but further increase in the extent of saponification led to the disappearance of the exotherm though the nitrile content was found to range between 4.5 and 2.2%. The saponified products beyond a degree of saponification of 0.755 showed a broad endothermic peak instead of the exotherm. Thermo-gravimetric analysis of the products revealed that the exothermic reaction was concurrent with the weight loss. In the polyacrylo-nitrile homopolymer the threshold decomposition temperature was 248°C as compared to 294.8°C for acryionitrile terpolymer. The residue at 800°C was less for the terpolymer, and it further decreased with increasing extent of saponification.

ISSN:0022-233X    

DOI:10.1080/00222338608063397

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Graft copolymers of acrylic acid on cellulosic materials were obtained by use of eerie ion in aqueous medium at different temperatures. The variation in the level of incorporation of poly(acrylic acid) grafts on the cellulosic substrate and the dependence of the water and saline retentions of the graft copolymers on the graft level are examined.

ISSN:0022-233X    

DOI:10.1080/00222338608063398

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Poly(α-methylolbenzoin methyl ether acrylate) and copolymers were prepared from a monomeric benzoin ether derivative, α-methylolbenzoin methyl ether acrylate, and photopolymerizations and photoreactions of those polymers were studied. The photosensitive polymer having benzoin methyl ether side chains showed a greater efficiency in photoinitiating capabilities than nonpoly-meric benzoin ether derivatives, such as benzoin, benzoin methyl ether, α-methylbenzoin methyl ether, and benzoin methyl ether acetate. Gelation by the polymeric photoinitiators predominated in photopolymerizations with vinyl monomers.

ISSN:0022-233X    

DOI:10.1080/00222338608063399

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Kinetics and mechanism of formation of urethane, biuret, allo-phanate, and isocyanurate in the synthesis of polyurethanes were studied by means of13C-NMR and GPC. In the spectra, the regions of urethane, allophanate, biuret, and isocyanurate were used to study the mechanism of reaction between isocyanates and glycols under different reaction conditions. Urethane groups give signals between 153 and 156 ppm; isocyanurate groups between 149 and 151 ppm. For the determination of secondary rate constants, the well-separated signals of urethane and allophanate in the13C-NMR spectra were used.

ISSN:0022-233X    

DOI:10.1080/00222338608063400

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Copolyamides containing α-diketone linkages were prepared from adipoyl chloride, 4,4′-dichloroformylbenzil, and hexamethylenedi-amine. Three polycondensation methods (unstirred interfacial, stirred interfacial, and solution method) were examined. The unstirred interfacial method gave soluble high molecular weight polymers. The copolymer composition was generally equal to that of the monomer feed. The content of the α-diketone linkage was varied from 5 to 20 mol%. The UV-induced gel formation was studied on films of copolyamides containing more than 10 mol% of the α-diketone linkage. The gel fraction, degree of gel swelling, changes in the IR spectrum, and Charlesby-Pinner' plots were examined. The photochemical reactions in the film are discussed.

ISSN:0022-233X    

DOI:10.1080/00222338608063401

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Poly(tetramethylene adipate) has been synthesized with and without14C labeling at different molecular weights. Degradation tests of the labeled powder inoculated with microorganisms showed a decrease in molecular weight (GPC) and first an increase and later a decrease of crystallinity (DSC). These changes also occurred in the inoculated material, and the results indicate that the degradation process was abiotic hydrolysis which first takes place in the amorphous region. The radioactivity measurements showed that the microorganisms are able to degrade further the oligomers formed during the hydrolysis. The rate of degradation is related to the molecular weight. Unlabeled poly(tetramethylene adipate) was extruded and cold drawn to yield oriented fibers. These fibers retained more than 50% of the original tensile strength during 100 days of abiotic in vitro hydrolysis.

ISSN:0022-233X    

DOI:10.1080/00222338608063402

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor