R.P. Burford

Chromatographic analysis of polyether based polyurethanes after alkali fusion

Abstract An analytical procedure for the characterization of polyether polyurethanes is reported. The diamine and polyether fragments are separated by gas and gel permeation chromatography after cleavage with molten alkali. Diamines were analysed as their trifluoroacetamide derivatives. The composition of the polyethers were determined by cleavage to the corresponding polyol acetates using mixed p- toluene sulphonic acid—acetic anhydride reagent and separation using gas chromatography.

Application of alkali and acid fusion reactions to the gas chromatographic analysis of silicone-polyester resins

Abstract An application of alkali and acid fusion reactions to the gas chromatographic (GC) analysis of silicone—polyester resins is described. The resins are cleaved into polyol, dicarboxylic acid and fatty acid fragments by means of hydrolytic fusion and then these fragments after separation and derivatisation are analysed using GC. The organic pendant groups on the siloxane part of the polymer are split off as the corresponding hydrocarbons. The methane and benzene thus formed is estimated by gas—solid chromatography.

Chromatographic analysis of polyester-based polyurethane elastomers after alkali fusion

Abstract An analytical procedure is described for rapid qualitative and quantitative analysis of polyester-based polyurethane elastomers. The elastomers are conventionally the complex reaction product of an isocyanate-terminated linear polyester prepolymer cross-linked with either a diamine or a diol chain extender. The polymer is cleaved into the corresponding diamine, dicarboxylic acid and glycol fragments by molten alkali fusion at high temperature. These products are analysed using gas and liquid chromatography, after separation using a liquid—liquid extraction procedure. Dicarboxylic acids are converted to dimethyl ester derivatives before gas chromatographic analysis while diisocyanate is examined as the diamines and diols, as liberated.

Chromatographic analysis of thermoplastic, medical-grade, polyether-based polyurethane elastomers

Abstract An analytical procedure is described for rapid qualitative analysis of medical-grade polyether-based polyurethane elastomers. The elastomers are conventionally the complex reaction product of an isocyanate-terminated linear polyether prepolymer with either a diamine or a diol chain extender. The polymer is cleaved into the corresponding diamine, polyether, diol, or hydrocarbon by molten alkali fusion at high temperature. These fragments are analysed by gas and gel-permeation chromatography, after separation by a liquid—liquid extraction procedure. Polyethers are further cleaved into the corresponding polyol acetates by using a mixed anhydride reagent, before gas chromatographic analysis.

Gas chromatographic analysis of polyether-based polyurethanes after acid fusion

Abstract An analytical procedure is described for rapid qualitative and quantitative analysis of polyether-based polyurethanes. Polyurethane foams are conventionally the complex reaction product of an isocyanate terminated branched polyether prepolymer extended with water. The polymer is cleaved into the diamine corresponding to the polyether portion of the polymer, by using mixed anhydride reagent. These products are analysed using gas chromatography after separation using liquid-liquid extraction procedure. The procedure is discussed and compared with an earlier reported scheme where the polymer was first fragmented by alkali fusion and the liberated polyether subsequently degraded using mixed anhydride reagent.

Chromatographic analysis of elastomer antidegradants and accelerators

Summary The use of various chromatographic methods in the analysis of all classes of elastomer antidegradants and accelerators is reviewed. The review of extraction methods is also included.

Gas chromatographic analysis of polyester-based polyurethane elastomers after acid fusion

Abstract An analytical procedure is described for the rapid qualitative and quantitative analysis of polyester-based polyurethane elastomers. The elastomers are normally the complex reaction products of an isocyanate-terminated linear polyester prepolymer cross-linked with either a diamine or a diol chain extender. The polymer is cleaved into the corresponding diamine, dicarboxylic acid and glycol acetate fragments by acid fusion using mixed anhydride reagent. These products are analysed by using gas chromatography, after separation using a liquid-liquid extraction procedure. Dicarboxylic acids are converted to dimethyl ester derivatives before gas chromatographic analysis, while diisocyanates are examined as the diamines and diols as acetyl derivatives.

Gas chromatographic procedure for the qualitative analysis of silicone polyester resins after alkaline fusion

Abstract The qualitative analysis of linear silicone polyester resins after alkali fusion is described. The identification of all fragments of the resins i.e. polyol, carboxylic acid, silicate, methane and benzene is achieved by gas chromatography. Polyol, carboxylic acid and silicate fragments are separated simultaneously as their trimethylsilyl derivatives.

Gas chromatographic analysis of cross-linked polyester-basedpolyurethane foams containing tri- and tetrafunctional alcohols after alkali fusion

Abstract An analytical procedure is described for rapid qualitative and quantitative analysis of polyester-based polyurethane foams containing tri- and tetrafunctional alcohols. The foams are conventionally the complex reaction products of an isocyanate-terminated partially cross-linked polyester prepolymer further cross-linked with water. The polymer is cleaved into the corresponding diamine, dicarboxylic acid and polyol fragments by molten alkali fusion at high temperature. These products are treated with trimethylsilylimidazole to convert polyols into volatile trimethylsilyl derivatives and hence to eliminate the extraction steps previously employed, which are of limited success with the polyfunctional alcohols. Dicarboxylic acids are converted after extraction into dimethyl ester derivatives. The polyol and acid derivatives and diamines corresponding to the diisocyanates were determined by gas chromatography.

The quantitative analysis of the polyester components of crosslinked silicone-polyester-aminoformaldehyde condensation products

Abstract Analysis of normally hydrolysis-resistant polymers, including silicone-polyesters, have recently been reported. Here we extend these methods to the analysis of condensation products of silicone-polyester resins and conventional butylated aminoplasts. Crosslinked systems employing butylated derivatives of urea-formaldehyde, melamine-formaldehyde and benzogaunamine have been degraded using an acetic acid-acetic anhydride reagent. Simultaneous hydrolysis of the polyester components and cleavage of both the ether crosslinks and the butoxy groups of the aminoplast occurred. Reaction conditions were also established where urea-formaldehyde, when used as a crosslinking agent, is simultaneously degraded using the same reagent. While the products were first examined as crosslinked condensation products, the procedures are also applicable to precondensation mixtures of the polyesters and the aminoplasts. The methods are suitable for quality control procedures.