摘要:

The copolymerizations of chlorotrifluoroethylene with propylene and isobutylene were carried out at 0 ∼ −78°C by γ-ray irradiation. It was found that alternating copolymers are obtained over a wide range of monomer composition for both systems. The alternating copolymer of chlorotrifluoroethylene with isobutylene was found to be highly crystalline, but the copolymer of chlorotrifluoroethylene with propylene was found to be amorphous. The copolymerizations were considered to proceed via a radical mechanism, but in the case of the isobutylene-chlorotrifluoroethylene system a cationic polymerization also takes place simultaneously at −78°C.

ISSN:0022-233X    

DOI:10.1080/00222337108069379

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Polymeric ultraviolet absorbers were prepared from 2-hydroxy-4-acryloyloxybenzophenone and 2-hydroxy-4-methacryloyloxybenzophenone and their inhibitive effect for photodegradation of polyethylene were examined by measuring mechanical strength, melt index, carbonyl group, and color difference. The polymeric ultraviolet absorbers were superior to the same type of ultraviolet absorber with low molecular weight in many properties, but inferior to Tinuvin, a commercial reagent, which has a different molecular structure. Therefore, within the ultraviolet absorbers examined, molecular structure seems to be a more important factor than molecular weight.

ISSN:0022-233X    

DOI:10.1080/00222337108069380

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Radical polymerization of methyl methacrylate initiated by the system cellulose-water-carbon tetrachloride was kinetically studied. Results obtained are: 1) The amounts of water, carbon tetrachloride, and cellulose affected the conversion. Michaelis-Menten's equation was applied to the relationship between the rate of polymerization and the amount of MMA. 2) Other methacrylates and acrylates were also polymerized by this system. 3) When methanol or ethanol was used instead of water, some weak polymerization activity was observed. 4) Initiating ability depended on the kind of cellulose used. 5) The activity of cellulose was not changed by washing with boiling water or by solvent extraction. 6) Polymerization was inhibited by the presence of air. 7) Heating in the presence of water and carbon tetrachloride markedly decreased the activity of the cellulose.

ISSN:0022-233X    

DOI:10.1080/00222337108069381

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Rates of 2–21−azobisisobutyronitrile initiated polymerization of methyl methacrylate in benzene were determined at 77.2, 65.0, and 50.0°C. The variation of molecular weight of the polymer with temperature and conversion was also studied. At a fixed conversion of 2.0%, the molecular weight decreased from 2.05 × 105at 50°C to 1.4 × 105at 77.2°C. The ratio of the propagation rate coefficient to the square root of the termination rate coefficient was found to be 0.61, 0.397, and 0.374 at 77.2, 65.0, and 50.0°C, respectively, with an uncertainty of ±0.5°C in temperature. The effect of active carbon on the rates of polymerization at 77.2°C was measured. Rates of polymerization decreased in the presence of active carbon. For example, the initial rate of polymerization decreased from 7.8 × 10−4mole/(liter min) to 4.6 × 10−4mole/(liter min) when the carbon concentration was varied from 0 to 9.65 g/liter. The molecular weight of the polymer increased from an average of 1.4 × 105in the absence of carbon to 1.5 × 105when carbon was present.

ISSN:0022-233X    

DOI:10.1080/00222337108069382

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Al-Ti oxychloride was prepared by reacting AlCl3and TiCl4with the equimolar amount of water in ethyl ether, followed by thermal treatment of the reaction product. Polymerization of ethylene with the catalyst consisting of AI-Ti oxychloride and Al(C2H5)3or (C2H5), AlCl was studied. With respect to the catalyst activity, Al/Ti oxychloride having a ratio of 1/1 was found most desirable, and the chlorine content in the oxychloride was of importance and significance. Hydrogen was used for controlling the molecular weight of the polymer. Two peaks of high catalyst activity were observed, one at about 70°C (slurry region) and the other at about 160°C (solution region). Effects of the conditions of polymerization with Al-Ti oxychloride-(C2,H5)2AlCl catalyst on the structure of the polyethylene, which was found to be of high density and high stiffness, are discussed. The amount of double bonds in the polyethylene was very small, but they were mostly of the vinyl group type.

ISSN:0022-233X    

DOI:10.1080/00222337108069383

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Propylene oxide was polymerized by a catalyst consisting of diethylzinc and α,β -unsaturated ketones. Ten α,β -unsaturated ketones and some other related compounds were examined. All methyl ketones were effective. α,β -Unsaturated phenyl ketones were effective except for a α,β-disubstituted derivative. α,β-Unsaturated carbonyl compounds other than ketones were practically ineffective. The initial step of the catalyst formation is considered to be the reaction of diethylzinc and α,β-unsaturated ketone which is either the conjugate addition to the α,β-unsaturated group or the hydrogen abstraction from the methyl group next to the carbonyl group. The conjugate addition gives the catalyst having larger activity and better stability at high temperature.

ISSN:0022-233X    

DOI:10.1080/00222337108069384

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

The equilibrium distribution of the electrons in the catalyst-oligoester-acrylates system was investigated. It was found that equilibrium distribution of electron in this system is determined by the ratio of catalyst concentration and electron attracting groups and, furthermore, by the possibility of electron exchange between the phthalate and methyl methacrylate groups of oligoesteracrylates. It was concluded that the anionic polymerization process of oligoesteracrylates has some peculiarities which distinguishes it from the anionic polymerization of vinyl monomers. That can probably be considered as a result of the “oligomer” molecules comprising two electron attracting groups that have different electron affinities which are separated by the system of o-bonds.

ISSN:0022-233X    

DOI:10.1080/00222337108069385

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

High molecular weight soluble polyphenyl-as-triazines were prepared at ambient temperature in m-cresol by the cyclopolycondensation of 2,6-pyridinediyl dihydrazidine (diamidrazone) with various aromatic dibenzil type reactants. Clear lemon yellow films, which exhibited good toughness and flexibility, were cast from solution. The isolated yellow polymers readily formed clear yellow to orange solutions in chloroform or sym-tetrachloroethane at concentrations as high as 30% solids. By TGA, polyphenyl-as-triazines exhibited a two-stage decomposition, commencing at ∼400°C, in both air and nitrogen. The polymers exhibited excellent stability at 260°C (500°F) in air, but at 290°C (554°F) significant weight losses occurred. Initial evaluation as an adhesive and resin matrix in Morganite I composites demonstrated the potential of polyphenyl-as-triazines as structural resins. Prior to polymer work, a series of model compounds were prepared and characterized.

ISSN:0022-233X    

DOI:10.1080/00222337108069386

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

6-Aminosaccharin and related monomers were subjected to polymerization as melts and in solvents. The products from these studies passed through soluble, hemipolymer stages corresponding to polyamide structures before being cyclized at higher temperatures to the final, insoluble, thermally stable polymers. Melt polymerization of 6-aminosaccharin as the triethylamine salt was the preferred procedure and yielded products of highest intrinsic viscosity (0.431 dl/g in N,N-dimethylacetamide).

ISSN:0022-233X    

DOI:10.1080/00222337108069387

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

The reaction mechanism of phosphorous acid and poly(vinyl alcohol) is presented. It has been found that there during this reaction mono- and diesters are formed in which most of the acid radicals are in the phosphonic form. To confirm the presence of this form in the product obtained, reactions with diethyleneamine and chloral have been carried out as characteristic tests for phosphonic groups. The occurrence of C—P bonds resistant to hydrolysis has been also found in the reaction product.

ISSN:0022-233X    

DOI:10.1080/00222337108069388

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor