Thermoplastic polymers as modifiers for urea-formaldehyde (UF) wood adhesives. I. Procedures for the preparation and characterization of thermoplastic-modified UF suspensions
Acrylic thermoplastic copolymers with different degrees of hydrophilicity were prepared and introduced into a commercial aqueous urea-formaldehyde (UF) suspension at 5-10% w/v. The most hydrophilic acrylic thermoplastic was introduced into the UF suspension as an aqueous solution, whereas the most hydrophobic acrylic was introduced as a surfactant-stabilized suspension. Acrylics with intermediate hydrophilicity were introduced into the UF suspension as a self-dispersed aqueous suspension. The thermoplastic-modified UF suspensions with 5% thermoplastic (58% solids) had a viscosity at 30°C of ∼ 114 cP, compared with a viscosity of ∼112 cP for the original UF suspension (60% UF solids). At 10% thermoplastic (63% solids), all the thermoplastic-modified UF suspensions exceeded 200 cP. The viscosity of the UF suspension modified with self-dispersed thermoplastic was reduced by ∼ 50% by reducing the thermoplastic molecular weight. SEM micrographs of cured thermoplastic-modified UF showed phase-separated thermoplastic domains in a continuous UF phase for the UF modified with self-dispersed and surfactant-stabilized thermoplastic, but UF modified with the water-soluble thermoplastic showed a single phase. © 2002 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 87.
Journal of Applied Polymer Science
Thermoplastic polymers as modifiers for urea-formaldehyde (UF) wood adhesives. I. Procedures for the preparation and characterization of thermoplastic-modified UF suspensions.
Journal of Applied Polymer Science,
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