Materials for Turbine Power Blades, Reinforcements, and Resins - Hybrid Anisotropic Materials for Wind Power Turbine Blades - page 80

50

Polyether polyurethane

30

Polybd/polyether Polyurethane

10

-10

-30

-50

0 5 10 15 20 25 30 35 40

Days @ 75°C

45 50 55 60 65 70 75

FIGURE 3.12
Change.in.tensile.strength,.hardness,.and.elongation.after.water.immersion.

3.8.3.5 Adhesion Properties

Adhesion.strength.to.both.galvanized.steel.and.aluminum.is.high,.charac-
terized.by.a.lap.shear.within.(758-1172)*10 4 .Pa.(American.Society.for.Testing.
and.Materials.(ASTM).D102)..It.changes.little.with.aging,.water.immersion.at.
room.temperature.and.boiling.point,.and.saltwater.immersion.

3.8.4 AIRTHANE PET-91A-Based Elastomers

This.approach.has.been.thoroughly.validated.by.the.General.Electric.Company.
as.a.part.of.the.program.to.construct.lightweight.aircraft.engine.blades.in.the.
late.1990s..Through.rigorous.trials,.a.material.with.superior.erosion.character-
istics.was.obtained.from.the.prepolymer.of.the.TDI.and.TMEG,.a.component.
commercially.supplied.by.GE's.Air.Products.and.Chemicals,.Inc..(Bridgeville,.
Pennsylvania),. namely. Airthane â . PET-91A.. When. cured. by. Bis-dianiline.
diamine.curative,.supplied.by.Lonza.(Basel,.Switzerland).under.the.trademark.
Lonzacure â ,. the. resulting. elastomer,. combined. with. N-phenylbenzamide.
(antioxidant). and. TINUVIN â . 765. (hindered. amine. light. stabilizer),. has. been.
molded.into.the.blade.metal.core.scaffold..The.new.composite.blade.led.to.sig-
niicant.manufacturing.cost.reduction,.weight.savings,.and.erosion.protection.
properties. veriied. by. substantial. testing. panels.. Subsequently,. the. program.
has. been. terminated. because. of. changed. corporate. priorities. and. the. tech-
nology.never.was.commercialized..Some.of.the.properties.of.the.Lonzacure.
Airthane.PET-91A.elastomer.are.given.in.Table 3.14. 35 .Multiple.variants.of.both.
prepolymer.and.cure.options.are.commercially.available.components.
NAT.intends.to.build.on.the.unrealized.potential.of.this.group.of.elasto-
mers.based.on.the.commercially.available.material.and.enhance.their.prop-
erties.for.heat.conductivity.
Many. characteristics. are. not. easily. attainable. by. polyacrylonitrile. (PAN)-
based.carbon.ibers..For.example,.PAN-based.ibers.have.a.maximum.modulus.