Additive group contributions to density and glass transition temperature in polyurethanes

• Published in: Polymer engineering and science 1998-12, Vol.38 (12), p.2072-2076
• Main Authors: Fedderly, Jeffry, Compton, Eric, Hartmann, Bruce
• Format: Article
• Language: English
• Subjects: Applied sciences; Evaluation; Exact sciences and technology; Measurement; Organic polymers; Physicochemistry of polymers; Polymers; Polyurethanes; Properties and characterization; Thermal and thermodynamic properties; Thermal properties
• ISSN: 0032-3888; 1548-2634
• DOI: 10.1002/pen.10377

The method of additive properties was applied to the density and glass transition temperature, Tg, of linear amorphous polyurethanes. This method assumes that certain polymer properties result from the additive effects of unique constituent group properties and that these group properties are independent of their environment. To determine the component properties, 14 model polyurethanes were synthesized. The polymers contained only the following four groups: urethane, phenylene, methylene, and ether oxygen. The densities and Tg's of these polymers were measured. Using these measured values, the known composition of each polymer, and an appropriate additive from, the molar component properties were calculated using a matrix least‐squares simultaneous fit algorithm. An error analysis confirmed that the component values were determined with greater accuracy than literature results. The densities ranged from 1.0 to 1.2 g/cm3 and measured versus predicted densities agreed to within 0.3% on the average. Tg's ranged from −70°C to 70°C and measured versus predicted Tg's agreed to within 1.3% on the average.