Materials for Turbine Power Blades, Reinforcements, and Resins - Hybrid Anisotropic Materials for Wind Power Turbine Blades - page 79

50

30

10

-10 Poly bd polyether polyurethane

-30

Polyether polyurethane

-50

0 5 10 15 20 25 30 35

Days at 75°C

40 45 50 55 60 65 70 75

FIGURE 3.10
Changed. tensile. strength. polybutadiene/polyester/polyurethane. composites.. (From. Li,. H..
1998.. Rheological behavior of vinyl ester resin .. Online. at. www.scolar.lib.vt.edu/theses.. With.
permission.)

50

30

10

Poly bd polyether polyurethane

-10

-30

Polyether polyurethane

-50

0 5 10 15 20 25 30 35 40

Days @ 75°C

45 50 55 60 65 70 75

FIGURE 3.11
Changed.hardness.of.polybutadiene.polyester/polyurethane.composites.

(Figure 3.12)..Additionally,.more.hydrophobic.materials.will.be.less.prone.to.
icing,.whereas.deicing.procedures.may.be.facilitated.

3.8.3.4 Low Temperature Flexibility

Another.attribute.of.the.polyurethane.systems.based.on.polybutadiene.res-
ins. is. their. outstanding. low. temperature. properties.. This. characteristic. is.
attributable.to.the.rubbery.polybutadiene.backbone.
Many.polyurethane.elastomers.derived.from.polybutadiene.resins.have.brit-
tle.points.as.low.as.-70°C..This.characteristic.of.the.polybutadiene.resin-con-
taining.formulations.also.contributes.to.excellent.thermal.cycling.properties.