Materials for Turbine Power Blades, Reinforcements, and Resins - Hybrid Anisotropic Materials for Wind Power Turbine Blades - page 77

damaging.them.and,.in.turn,.causing.turbulence.that.negatively.affects.aero-
dynamics.and.reduces.output.
“We've.seen.irsthand.the.damage.caused.by.leading.edge.erosion.when.
conducting. our. inspections. for. wind. turbine. maintenance. and. repairs,”.
said.Chris.Bley,.director.of.business.development.for.Rope.Partner..“We've.
seen. sites. where. signiicant. erosion. occurs. in. as. little. as. two. years. after.
installation.”
The.study.is.important.because.wind.turbine.maintenance.is.costly.and,.
thus,. of. concern. to. investors.. An. unscheduled. crane. to. access. failed. parts.
can. run. $70,000;. anything. to. cut. down. on. emergency. maintenance. calls. is.
effectively.money.in.the.bank.
3M's.interest.lies.in.its.expertise.with.polyurethane.tape,.which.it.offers.for.
application.in.the.wind.power.and.aerospace.industries..One.example.is.its.
use.on.helicopter.blades.

3.8.3 Polybutadiene Resins

Careful. analysis. carried. out. by. the. “NAT. (Neo. Advent. Technologies. LLC).
team,”.identiied.polybutadiene.resins.and.polyurethane.derived.from.it.as.a.
promising.material.for.generating.an.erosion-resistant.polymer.framework..
Frequent.heating.of.this.material.for.deicing.purposes.presents.the.challeng-
ing. task. of. having. a. polymer. with. high. stability. at. elevated. temperatures..
This.can.be.addressed.with.polybutadiene.resins.
Polybutadiene.resins.are.a.novel.class.of.the.hydroxyl-terminated.polybu-
tadiene.homopolymers.with.a.structure.that.is.depicted.in.Figure 3.8.
They.are.low.molecular.weight.reactive.liquids.that.offer.broad.formulat-
ing.opportunities..Several.key.attributes.are.responsible.for.the.formulating.
advantages.provided.by.polybutadiene.resins.

3.8.3.1 Hydroxyl Functionality

Polybutadiene.resin.end.groups.are.predominantly.primary.allylic.hydroxyl.
groups. (Figure 3.9). 34 . These. groups. have. high. reactivity. with. a. variety. of.
isocyanates.to.yield.polyurethane.polymers..The.hydroxyl.functionalities.of.
the. two. widely. used. grades,. polybutadiene. R-45HTLO. and. polybutadiene.
R-20LM,.are.typically.2.4.to.2.6.per.polymer.chain.

HO OH

n

0.6 0.2 0.2

FIGURE 3.8
Chemical.structure.of.the.polybutadiene.resins.(n.=.50.for.polybutadiene.R-45HTLO;.n.=.25.
for.Poly.butadiene.R-20LM)..(From.Li,.H..1998.. Rheological behavior of vinyl ester resin ..Online.at.
www.scolar.lib.vt.edu/theses..With.permission.)