Polyurethane flexural modulus-temperature

Morimoto and Suzuki (12) studied the flexural properties of continuous-glass-fiber-strand mat-reinforced rigid polyurethane foam, and found that both the flexural modulus and the flexural strength increased and the temperature dependence decreased when longer fibers were used as reinforcement. The density of the matrix foam also enhanced these tendencies. 

Neither the uniform strain model nor the uniform stress model is appropriate for this microstructure. Consequently, the elastic moduli of polyurethanes lie between the limits set by Eqs (4.11) and (4.12). For a network chain of Me = 6000, the rubber elasticity theory of Eq. (3.20) predicts a shear modulus of about 0.4 MPa. The hard blocks will have the typical 3GPa Young s modulus of glassy polymers. Increases in the hard block content cause the Young s modulus to increase from 30 to 500 MPa (Fig. 7.13). For automobile panel applications it is usual to have a high per cent of hard blocks so that the room temperature flexural modulus is 500 MPa. 

Polyurethan- ethermo-plastic elastomer 24 0.003 700 NA 1.06 Elongation at break, low temperature characteristics and detergent resistance Tensile strength and flexural modulus... 

---