摘要:

This paper is concerned with charge transfer complex properties of copolymers with pendant electron-donor and electron-acceptor groups obtained by radical copolymerization. The complexing groups were carbazolyl, anthryl, phenothiazinyl, and p-dimethyl-aminobenzyl as electron-donor groups, and picryl, dinitrophenyl, dinitrobenzoyl, and trinitrofluorenyl as electron-acceptor groups. The microstructure of such copolymers, including the tendency to alternating and coisotactic addition, together with the influence of monomer structure and reaction conditions, is discussed. Intramolecular complexation interactions are analyzed. These properties were measured by means of1H-NMR and electronic absorption spectra. Finally, some physical properties, e.g., color, solubility, density, and photoconductivity, are presented to illustrate the intramolecular and intermolecular complexation interactions. It is concluded that such copolymers are weak charge transfer complexes of the π-π type. They are of theoretical interest for study of the correlation between synthesis, structure, and properties, and of practical interest due to their optoelectric properties.

ISSN:0022-233X    

DOI:10.1080/00222338508056631

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Techniques for chloromethylation of polyarylether sulfones, poly-phenylene oxide, phenolic resin, and a model compound for the polyarylether sulfone are described. The rates of quaternization of chloromethylated polyarylether sulfone, I, and the corresponding model compound, II, with triethylamine, tri-n-butylamine, and quinuclidine in either DMSO or DMSO/dioxane are reported. Second-order kinetics are observed in the quaternization of II for the entire range of substitution. In contrast, quaternization of I followed second-order kinetics during the initial 35–60% of reaction only; higher degrees of quarternization occurred at reduced rates. After evaluating the potential impact of steric hindrance, added electrolyte, and initial extent of chloromethylation, the decrease in quaternization rate at high degrees of substitution is attributed to steric effects imposed by restricted rotation of the polymer chain. Comparable retardations are not observed during the quaternization of chloromethylated polystyrene under identical conditions.

ISSN:0022-233X    

DOI:10.1080/00222338508056632

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A new procedure for the synthesis of porous and nonporous polyvinyl alcohol beads by controlled methanolysis of different concentrations of polyvinyl acetate suspension is described. By crosslinking with epichlorohydrin, insoluble crosslinked polyvinyl alcohol gels were obtained. These gels exhibit some peculiar swelling properties related to the reticulation degree, probably due to the interchain hydrogen associations. Crosslinked polyvinyl alcohol beads can be used as supports for liquid chromatography and for enzyme immobilization. Some new stationary phases for affinity chromatography and for ion-exchange chromatography were obtained. No substantial modifications in the catalytic properties of enzyme immobilized on crosslinked polyvinyl alcohol gels were established.

ISSN:0022-233X    

DOI:10.1080/00222338508056633

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The basic chemistry underlying the successful synthesis of poly-(enaminoesters) by vinylogous nucleophilic substitution is examined. It is concluded that a new mechanism must be operative. A Michael addition followed by elimination of a volatile fragment is proposed.

ISSN:0022-233X    

DOI:10.1080/00222338508056634

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Plasma-induced polymerization (copolymerization) is a new method of polymer synthesis. Different comonomer pairs (methyl methacrylate-styrene, methyl methacrylate-α-methylstyrene, acrylonitrile-α-methylstyrene, methacrylonitrile-styrene, butyl methacrylate-styrene) have been copolymerized by this technique. The results showed that the process proceeds through a living radical mechanism and yields ultrahigh molecular weight macromolecular compounds (pleistomers). So, the reactivity ratio values of the monomers copolymerized by this technique are very close to those yielded by their classical radical copolymerization, and the microstructure of the copolymers is similar to that of their radically obtained homologs. Some characteristics, as well as some solution properties, of the ultrahigh molecular weight copolymers obtained are also presented.

ISSN:0022-233X    

DOI:10.1080/00222338508056635

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The characterization of polymers by pyrolysis directly in the ion source of a double focusing magnetic sector mass spectrometer, operating in the chemical ionization mode, is described. Pyrolysis is achieved by two different probe techniques. A low temperature, slow heating rate direct insertion probe (DIP) is used at 400°C, and a specifically constructed high temperature, fast heating rate, high temperature pyrolysis (HTP) probe is used at 1000°C. This probe is capable of achieving pyrolysis temperatures of 1200°C at controlled heating rates up to 20,000°C/s. The mass spectrometric analysis of the pyrolysis products was achieved under chemical ionization (CI) conditions utilizing methane, isobutane, and ammonia as reagent gases. Under CI conditions the molecular ions formed in the mass spectrometer show little tendency to fragment. The CI mass pyrograms are very simple, with each peak in the spectra ascribable to a particular component in the pyrolysis product mixture. The results of the two probe pyrolysis techniques are compared and the utility of each technique for the characterization of polymers is demonstrated using the vinyl polymers polymethyl methacrylate, polyvinyl chloride, and polystyrene.

ISSN:0022-233X    

DOI:10.1080/00222338508056636

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Polybutadiene (PB) can be easily halogenated by reaction with iodine chloride or bromine in tetrahydrofuran. The resulting glassy polymers were reacted with n-butyllithium, sec-butyl-lithium, and polystyryllithium in THF. Iodochlorinated PB gave a polybutadiene with a different cis/trans ratio with n-BuLi. The reformation of PB was accompanied by partial crosslinking. The reaction probably involved a halogen-metal exchange followed by intra- and intermolecular elimination of Li halide. With brominated PB, both coupling and elimination took place. With sec-BuLi, an allylic iodine derivative was obtained from iodochlorinated PB, probably by dehydrochlorination. The iodinated intermediate can easily undergo a coupling reaction with further sec-BuLi. Both iodochlorinated and brominated polybutadienes gave graft copolymers by reaction with polystyryllithium in THF. Grafting was always accompanied by gel formation.

ISSN:0022-233X    

DOI:10.1080/00222338508056637

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

We have synthesized several polyanionic polymers for biological evaluation and to probe the mechanism of macrophage activation. We have determined that, while the molecular weight of the polymers is toxicologically important, the hydrophlicity, chain rigidity, and surface charge play a significant role with respect to the degree of macrophage activation. Macrophages elicited with polyanionic polymers with hydrophobic groups were cytotoxic to Lewis lung carcinoma both in vitro and in vivo. However, macrophages stimulated by polymers with high carboxylic acid group density but little hydrophobicity did not demonstrate significant antitumor activity.

ISSN:0022-233X    

DOI:10.1080/00222338508056638

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

This paper presents the synthesis of certain polyimides which contain one of the following heterocycles: oxadiazole, benzox-azinone, benzthiazole. Their properties, particularly thermal stability and hydrolytic stability, are compared to fully aromatic polyimides. Poly-1,3,4-oxadiazole-imides have been synthesized either by the reaction of ditetraeole monomers which contain preformed imide cycles with diacid chlorides, or by the reaction of an aromatic diamine containing a preformed oxadiazole ring with diacid chlorides containing preformed imide rings. Polybenz-oxazinone-imides have been synthesized by polycondensation of a bis(amino acid), 4,4′-diaminodiphenylmethane-3,3′-dicarboxylic acid, with diacid chlorides containing preformed imide rings. Polybenzthiazole-imides have been obtained by polycondensation of aromatic diamines containing a preformed benzthiazole ring with diacid chlorides containing preformed imide rings. Thermal stabilities of these heterocyclic polyimides are similar and in certain cases are higher than those of fully aromatic polyimides. It was also found that the hydrolytic stability of heterocyclic polyimides is definitely superior to that of aromatic polyimides.

ISSN:0022-233X    

DOI:10.1080/00222338508056639

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The reaction of cycloolefins with the components of the catalytic system WCl6/epichlorohydrin/Al(iBu)3, active in the ring-opening polymerization of cycloolefins, was investigated in order to get additional information on the mechanism of polymerization. The study led to the following conclusions. 1) Olefin complexation with the transition metal has a decisive influence on active center formation. 2) Trivalent tungsten species resulting from fast reduction of the cycloolef in/transition metal complex by aluminum alkyl or from a slow reduction process d W(VI) in the presence of cycloolef in alone, show a particularly high activity in ring-opening polymerization. 3) In the case of tricomponent systems (e.g., WCl6/Al(iBu)3/ epichlorohydrin or WCl6/Al(iBu)3/chloranil), the nature of the third component has a decisive effect on both polymerization kinetics and the molecular weight and structure of the resulting polymer. The data are discussed in the context of a reaction mechanism based on carbene complexes as active centers.

ISSN:0022-233X    

DOI:10.1080/00222338508056640

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor