摘要:

Polymerizable vinyl- and isopropenyl derivatives of 2, 6-di-t-butyl-phenol have been synthesized, polymerized, and copolymerized. 2,6-Di-t-butyl-4-vinylphenol and O-acetyl-2, 6-di-t-butylphenol were prepared in yields of 50 and 80%, respectively, starting from 2,6-di-t-butylphenol. 2,6-Di-t-butyl-4-isopropenylphenol was also synthesized in nearly 50% yield. The two hindered phenol monomers and some of their acetyl derivatives were copolymerized with styrene, methyl methacrylate, and n-butyl acrylate.

ISSN:0022-233X    

DOI:10.1080/00222338608081111

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The effect of p-toluenesulfonic acid and phosphoric acid on the cyclodehydration of quinazolone prepolymers has been investigated. Isothermal weight loss during the curing process was monitored closely to follow the extent of cyclization. The optimum weight loss corresponding to 2 mol water is used as an indication of the formation of a fully cyclized quinazolone structure without concurrent decarboxylation. This can be achieved by incorporating the catalyst at 2 wt% concentration, which permits a lower curing temperature than those previously reported. The polymers formed in the presence of catalyst have thermal stability superior to those prepared without catalyst. The glass transition temperature is also raised. This we conclude to be a direct result of the decrease in the amount of incomplete quinazolone rings along the polymer backbone as a result of more efficient cyclization catalyzed by the acids.

ISSN:0022-233X    

DOI:10.1080/00222338608081112

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Vinyltris(methoxyethoxy)silane (VTMES)was copolymerized with methyl methacrylate (MMA) and styrene (St) in bulk at 60°C using benzoyl peroxide as free radical initiator. The copolymer compositions were determined from elemental analysis, and reactivity ratios were calculated by the Kelen-Tüds graphical method. For MMA-VTMES, r1= 11.2 ± 0.88 and r2= 0 ± 0.16, and for St-VTMES, r1= 11.2 ± 2.0 and r2= 0 ± 0.34. In both systems r2is near zero, indicating that VTMES undergoes little or no polymerization under the experimental conditions. The influence of the silicon comonomer on some of the basic properties of the copolymers (e.g., intrinsic viscosity, solubility, and thermal behavior) was studied.

ISSN:0022-233X    

DOI:10.1080/00222338608081113

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A rigorous statistical method is established to compute the rate constants of the bimolecular decomposition of redox catalysts used to initiate polymer chains. Results obtained for the systems styrene-dimethylaniline-benzoyl peroxide and acrylamide-thio-glycollic acid-potassium bromate compare favorably with those reported by other workers. The merits of this error-in-variable technique, which outperforms conventional nonlinear least-square analysis and the dead-end polymerization method, are discussed.

ISSN:0022-233X    

DOI:10.1080/00222338608081114

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Graft copolymerization of mixtures of acrylic acid and acrylonitrile (AN) onto irradiated cellulose was studied. The effects of radiation dose, temperature, duration, and concentration of the monomers were investigated. The extent of grafting was found to increase with radiation dose, temperature, and duration. Grafting was higher with increasing AN concentrations.

ISSN:0022-233X    

DOI:10.1080/00222338608081115

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

β-Picolinium-p-chlorophenacylide initiates radical polymerization of methyl acrylate (MA) up to 19.5% conversion without gelation due to autoacceleration. The average rate of polymerization (Rp) increases as [ylide] is raised from 1.02 to 3.06 mmol/L, the order of reaction being 0.5 ± 0.02. However, at higher concentrations (>3.06 mmol/L), Rpdecreases. The monomer exponent is 1.40 when benzene is used as diluent. The overall energy of activation is computed to be 28.8 kJ/mol. A polar solvent like dimethyl-sulfoxide and a radical scavenger like hydroquinone retard the reaction. The kinetic data and ESR studies indicate that the polymerization proceeds via a free-radical mechanism. Chain termination by degradative chain (initiator) transfer appears to be significant.

ISSN:0022-233X    

DOI:10.1080/00222338608081116

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Anionic polymerization of acrolein (AL) by imidazole in the presence of several p-substituted phenols such as phenol, p-methyl-phenol, and p-nitrophenol were kinetically carried out in tetra-hydrofuran at 0°C. The initial polymerization rate Rpwas estimated from the rate of monomer consumption by means of gas chromatography. A linear correlation was obtained from Hammett's equation, log RpX/RpH = 0.22. Meanwhile, the polymerizabilities were found to be in the following order: p-methylphenol > phenol > p-nitrophenol. The additive effect of phenols was kinetically discussed on the basis of these results.

ISSN:0022-233X    

DOI:10.1080/00222338608081117

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Acrylic acid (AA) and acrylamide (AAm) were graft copolymerized onto polyethylene powder by the preirradiation method. The PE powder grafted with both AA and AAm (PE-g-(AA-co-AAm)) rapidly adsorbed Tb ion with an efficiency higher than did PE powder grafted with AA (PE-g-AA). The complex formation constant of Tb ion with PE-g-(AA-co-AAm) was larger than that with PE-g-AA because the introduction of the acrylamide part decreased the steric hindrance for complexation between Tb and the carboxyl group of the graft chains. Tb ion was efficiently separated from transition metal ions, such as Co, upon passage of a solution through a column packed with PE-g-(AA-co-AAm).

ISSN:0022-233X    

DOI:10.1080/00222338608081118

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The microstructure of ion-exchange resins has been investigated to understand more clearly the ion-exchange mechanism. Nine types of resins with different pore structures were used: all of the polystyrene family crosslinked with divinylbenzene and anionic resins, with mesh sizes ranging from 100 to 200, except for one (20–50 mesh). Various pore volumes of each resin were determined by measurements of intrusion of some chemical species (H2O, Nd3+, and Hg) into the resin. The results are analyzed on the basis that an ion-exchange resin particle consists of four regions. They are: 1) the mercury intrusion region, 2) the region where coions (such as Nd3+) can intrude but mercury cannot, 3) the region where water or counterions can intrude but coions cannot, and 4) the polymer matrix region occupied by the polymer skeleton. The former two regions are not influenced by the resin-fixed ionic groups. While it used to be thought that specific adsorption of counterions may occur in the entire exchange resin particle, it is appropriate to consider that specific adsorption takes place only in the latter two regions. According to this point of view, the adsorption equilibrium of the Fe3+/Cl−complex ions could be explained more satisfactorily.

ISSN:0022-233X    

DOI:10.1080/00222338608081119

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:10.1080/00222338608081110

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor