摘要:

The synthesis and the characterization of poly (methyl methacrylate) (PMMA) grafted to poly(vinyl chloride) (PVC) through benzodithioate groups are studied. Unlike results generally obtained with conventional free-radical initiators for systems involving PVC and MMA, high conversions, and grafting efficiencies are achieved with azobis-isobutyronitrile. The paper describes the synthesis of p-vinylbenzodithioate-containing PVC and the dependence of the characteristics of PVC-g-PMMA on the composition of the reaction mixture. Characterization of the graft copolymers includes UV and IR spectroscopy, GPC, and microstructure analysis by removal of PMMA side chains by aminolysis of dithioesters groups. Intrinsic viscosity, glass transition temperature, and thermal sensitivity were investigated to confirm the grafted nature of the copolymer.

ISSN:0022-233X    

DOI:10.1080/00222338608081121

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Trimethylvinylsilane was found to polymerize anionically in cyclo-hexane much like styrene or dienes, except for the occurrence of a termination step. The propagation and initiation reactions were found to be first order with respect to trimethylvinylsilane and one-half order with respect to the initiator and chain ends initially, but first order after the initiator was consumed. Rate constants for initiation, propagation, and termination were found to increase in the presence of ethers, with the termination rate constant increasing the fastest. In the absence of ethers, the propagation rate constant is small, 1.4 mL1/2/(mol1/2min) at 22°C.

ISSN:0022-233X    

DOI:10.1080/00222338608081122

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Several new polymeric antioxidants have been synthesized based on 2,6-di-t-butyl-4-vinyl (or isopropenyl) phenol. They were prepared by emulsion copolymerization with 1,3-butadiene or isoprene and had about 6 to 10 mol% of the polymerizable hindered vinyl (or isopropenyl) phenol in the copolymers. The copolymers were catalytically hydrogenated in the presence of soluble cobalt catalysts to saturated copolymers of ethylene or ethylene/propylene structure. The polymers are apparently not branched and had molecular weights up to 50 000.

ISSN:0022-233X    

DOI:10.1080/00222338608081123

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Vinyl acetate and citraconic anhydride are known to give 1:1 radical alternating copolymers regardless of the monomer feed composition. The mechanism of this copolymerization involves free monomers and a charge-transfer complex between them. We undertook a study of the microstructure by NMR and thermogravimetric analysis (study of the thermal cis elimination of acetic acid). We determined a quantitative correlation between the theoretical proportion of D-A diads obtained in the reaction corresponding to the addition of the complex between comonomers on the growing chain and the microstructure of the copolymers determined by thermogravimetric analysis.

ISSN:0022-233X    

DOI:10.1080/00222338608081124

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The cationic polymerization of ethylene oxide by trityl salts (BF4−, SbCl6−, AsF6−, and PF6−as counterions) in nitrobenzene at different temperatures has been studied. The kinetic analysis was carried out by use of an automatic manometer, and it showed that the polymerization rate constant depends neither on the counterion type nor on the initial initiator concentration. These facts allowed us to conclude that macrocations and macroion pairs have the same reactivity.

ISSN:0022-233X    

DOI:10.1080/00222338608081125

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Bulk condensations of bissilylated Bisphenol A and tetrachloro-hydroquinone with various aryl phosphorodichloridates (phosphoric acid arylester dichlorides) were conducted at temperatures between 180 and about 300°C. Only when the pentachlorophenylester of phosphoric dichloride was condensed was partial crosslinking observed. Yields in the range of 80–95%, and [Mbar]nof ∼ 12 000 were obtained. DSC measurements above 25°C show Tgin the range of 65–145°C, whereas melting endotherms were never found. Thermo-gravimetric analyses indicate that the thermal stability decreases with an increasing number of chlorines in the aryloxy group. Consequently, the fully chlorinated polyphosphate possesses the lowest thermal stability.

ISSN:0022-233X    

DOI:10.1080/00222338608081126

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The cloud-point curve for the system copoly(ethylene-vinyl acetate) plus methyl acetate has been measured by a simple visual method. The critical point was determined by using the phase volume ratio method. The method of continuous thermodynamics was applied for thermodynamic treatment. The composition of the copolymer is described by a divariate distribution function assumed as a generalized Stockmayer distribution. The activity coefficients were obtained with the aid of the Huggins Chi -parameter concept assuming Chi to be a quadratic polynomial with respect to the weight-average chemical composition of the copolymer. The three model parameters were calculated from the critical point and the slope of the cloud-point curve at the critical point. The cloud-point curve and the shadow curve were predicted from these parameters. The cloud-point curve shows qualitative agreement with experimental data.

ISSN:0022-233X    

DOI:10.1080/00222338608081127

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Polymeric ultraviolet absorbers have been synthesized by free-radical solution copolymerization in cyclohexanone at 70°C of methyl methacrylate and 2-hydroxy-4-acryloyloxybenzophenone at low (below 10%) conversion of monomers. The composition of the copolymers was determined by UV, IR, and NMR. The reactivity ratios were determined and the effect of copolymer composition on viscosity was studied. The copolymers were also studied by TGA and DSC. The latter showed the effect of copolymer composition on the glass-transition temperature.

ISSN:0022-233X    

DOI:10.1080/00222338608081128

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Calculations [1] of rheological properties of polymeric solutions have usually been restricted to very dilute o r to very concentrated solutions. In either case, one starts with a model for the micro- structure. Between these two conceptual extremes lies the broad class of moderately concentrated solutions. To cover this region theoretically, two approaches have been used; 1) network theories focusing attention on entanglement junctions, and 2) single-molecule theories focusing attention on single molecules but including inter- molecular interactions. Williams, Wang, and Zimm introduced a double model; one for a particular macromolecule and another for solutions containing like molecules in which the chosen macro- molecule is suspended. This approach has turned out to be quite successful because spheres immersed in a suspension of like spheres behave as i f suspended in a Newtonian fluid, and the resulting ex- pression for viscosity is quite simple in form and qualitatively correct for moderate concentrations.

ISSN:0022-233X    

DOI:10.1080/00222338608081129

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0022-233X    

DOI:10.1080/00222338608081120

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor