摘要:

The mechanism of action of quaternary ammonium salt catalysts in the synthesis of aromatic polyesters was investigated. The possibility of formation of compounds of these salts and bisphenols and their extraction in the form of an ion pair into the organic phase was investigated. The structure of the compounds obtained was determined.

ISSN:0022-233X    

DOI:10.1080/00222337908066614

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Reaction rates of interfacial polycondensation of bisphenol A and chlorobisphenol II with isophthaloyl chloride were investigated. Rate constants and activation energies were determined The reaction rate was found to depend on stirring speed, catalyst, type of bisphenol, and temperature.

ISSN:0022-233X    

DOI:10.1080/00222337908066615

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

p,p′-Phenolphthalein-bis(trimellitic) dianhydride was obtained by the reaction of diacetyloxyphenolphthalein with trimellitic anhydride. The structure of the new compound was proved by elementary analysis, infrared spectroscopy, and acid value determination. The course of acidolysis reaction was examined in the temperature range of 240–280°C. The compound obtained is a powder having a melting point of 135–138° C, has high thermal stability, and is easily soluble in many organic solvents and low-molecular epoxy resins. Application of p,p′-phenolphthalein-bis(trimellitic) dianhydride in synthesis of soluble polyester-imides and as a hardening agent for low molecular weight epoxy resins is proposed.

ISSN:0022-233X    

DOI:10.1080/00222337908066616

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Hardening of a low molecular epoxy resin with p,p′-phenol-phthalein-bis(trimellitic) dianhydride has been studied by using differential scanning calorimetry. The relationships of glass transition temperature of the systems being examined versus time, temperature of hardening, and dianhydride content in the compositions have been determined. The activation energy of crosslinking reactions in systems containing 50% of the stoichiometric amount of dianhydride has been evaluated. The value of activation energy obtained indicates a high reactivity of dianhydride in the examined reactions. The hardened epoxy composition exhibits excellent thermal stability, good hardness, and good resistance to acid solutions.

ISSN:0022-233X    

DOI:10.1080/00222337908066617

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Alternating polyesterimides soluble in m-cresol, dimethyl-formamide, and dimethyl sulfoxide have been obtained by the reaction of p,p′-phenolphthalein-bis(trimellitic) dianhydride with primary aromatic diamines. The course of reaction between dianhydride and diamines and the cyclization process of polyesteramidoacids have been studied. One-step synthesis of polyesterimides by polycyclization in m-cresol solution has been developed. The coatings from polyesterimides prepared possess good thermal stability and advantageous mechanical properties.

ISSN:0022-233X    

DOI:10.1080/00222337908066618

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

This paper describes the attachment of sugar (sucrose) onto low molecular weight poly(vinyl alcohols) (etherification) to produce a new class of synthetic sweetener. Because of its regulated molecular weight, the new sweetener would pass through the digestive tract and be excreted in its original molecular form. We have termed the new class of sweeteners poly-sugar. The etherification of sucrose with poly(vinyl alcohol) can be carried out either in dimethyl sulfoxide or water. We have prepared poly-sugars with varying degrees of etherification (3.4–5.4). Highly etherified products were bitter, but a poly-sugar with a 4.23 degree of etherification was sweet without any bitter aftertaste.

ISSN:0022-233X    

DOI:10.1080/00222337908066619

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Block polymers of AB, BAB, and ABA type, derived from preformed poly(ethylene oxide) (PEO) of different molecular weight and hydroxy-terminated polybutadiene (HTPB) were prepared. Poly(ethylene oxide-b-butadiene) and poly(butadiene-b-ethylene oxide-b-butadiene) were prepared by reaction of PEO, which was previously endcapped with TDI, with HTPB at a 1:1 or 1:2 reactants molar ratio. Poly(ethylene-oxide-b-butadiene-b-ethylene oxide) were prepared by reaction of isocyanate-endcapped HTPB with PEO at a molar ratio of reactants of 2:1. High reaction yields were obtained. Correlation between tensile properties and water absorption with block polymer composition was found.

ISSN:0022-233X    

DOI:10.1080/00222337908066620

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Poly(ethylene oxide-b-3,3-dimethylthietane) was prepared by coupling of preformed poly-3,3-dimethylthietane (PDMT) with poly(ethylene oxide) (PEO). PDMT was endcapped with 2,4-toluene diisocyanate (TDI) and then reacted with molar excess of PEO. AB type block polymers were obtained. Absorption by complexation of silver nitrate and iodine by these block polymers was investigated. It was found that the presence of the PEO segmer in the block polymer was essential for complexation. Iodine absorption was not accompanied by other side reactions leading to chain scission of the polysulfide, as was found with poly(propylene sulfide).

ISSN:0022-233X    

DOI:10.1080/00222337908066621

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Some structurally and molecularly uniform phenolic oligomers with additional functional groups have been prepared by known methods of stepwise synthesis, and their dissociation behavior in nonaqueous solvent has been studied by electrometric titration techniques. Hyperacidity and stepwise neutralization of some of the functional groups in the oligomer molecules have been interpreted in terms of intramolecular hydrogen bonding, homoconjugation, and ion association in a medium of low dielectric constant.

ISSN:0022-233X    

DOI:10.1080/00222337908066622

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Hydroxy radical-initiated poly(methyl methacrylate) and polystyrene have been reacted with o-sulfobenzoic anhydride to produce dye-active sulfonate groups and these were measured by a dye-partition technique with methylene blue. The important advantages over chlorosulfonic acid, previously employed in the dye-partition analysis for the conversion of hydroxy into sulfate groups, are that o-sulfobenzoic anhydride does not react at sites other than the hydroxy functionality and that it introduces the dye-active moiety (sulfonate) into the polymer via a hydrolytically more stable linkage.

ISSN:0022-233X    

DOI:10.1080/00222337908066623

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor