摘要
A method of preparing stable, film-forming polyurethane latices without the use of emulsifying agents is described in this article. The reaction of polypropylene glycol with a stoichiometric ratio(NCO:OH=2:1) of tolylene-diisocyanate in the presence of ketones and catalyst produces an isocyanate terminated prepolymer. Then addition of diethylene glycol as chain extender to prepolymer solution can yield a relatively high molecular weight poly(urethane-ether) which is readily dispersed with aqueous tartaric acid after tartaric acid and water diffuse into the suspended globules of the latex and produces the chain extended urethane. A linear or crosslinked high molecular weight self-emulsifiable polyurethane carl be obtained due to the reaction of the hydroxy group of tartaric acid and little water with isocyanate endgroups. The results of FTIR also show that an expected polyurethane emulsion has been successfully synthesized.
A method of preparing stable, film-forming polyurethane latices without the use of emulsifying agents is described in this article. The reaction of polypropylene glycol with a stoichiometric ratio(NCO:OH=2:1) of tolylene-diisocyanate in the presence of ketones and catalyst produces an isocyanate terminated prepolymer. Then addition of diethylene glycol as chain extender to prepolymer solution can yield a relatively high molecular weight poly(urethane-ether) which is readily dispersed with aqueous tartaric acid after tartaric acid and water diffuse into the suspended globules of the latex and produces the chain extended urethane. A linear or crosslinked high molecular weight self-emulsifiable polyurethane carl be obtained due to the reaction of the hydroxy group of tartaric acid and little water with isocyanate endgroups. The results of FTIR also show that an expected polyurethane emulsion has been successfully synthesized.
