Toughening at nanoscale makes plastics suitable for aircraft use

Russian researchers achieve synthesis of high reactivity lanthanide catalysts inve~tig:lted

A bn.-akthrough by research-

usually contain a cyclopenwdi·

Proceedings of Russian Acarl-

They ;l1so

ers at the Instillue of Organo-

cnyl moiety. which

incrc-.lSC~

em)' oj Sciences: CbemistlJ' (2000. No 5. p.9r).

acti\"ity of complc..x hydrides of

metallic Chemistry in Nizhny No\'gorod looks set 1O 010\'(: me dcn::lopmcnt of lanthanjdc comple..es as cataJyslS for po-

t.heir stability bllt dccreaSt..'"S cat-

a.lytic acth;ty and reactivity of

the

Eu and Sm as well as of the earlier obl hydride as cat"

the w-H group.

Applying the original

s~llthetic

alysts in polymerization. It was

'ymeri7..uion 11C
nle Russian

repon

procedure. the chemisb obtained the lanthanide hydrid<..-s

found that lhe:o.e compowl
report on

Lhat they ha\'e pioneered the synthesis of molecular hydri-

bound with tetrahydrofur.m

According to

(Il-IF). TIle hydrides are amor·

Chemweb.com chemists ha\Tc

des of bhdlem europium and

phous I>o\vders of dark-red

10 propylene e\'en at pressures as high as 20 atmospheres. but

focUS<.--d on hydride complc..xes

samarium that do not contain

(for samarium) or orange (for

ext remcly acth'e in styrene

of lamh:U1ides as potential cata-

C'J.rbocycl.ic Ijgands. nlC S)'llth· esized compounds have an un-

europium) colours. A com· position of hydrides was CSL'1b-

polymeri7..ation.lt is interesting that the average molecular

sarurJ.ted co-ordin:nion sphere

lished by using infr.l-red spectroscopy ;Uld l\~tR methods.

depends on the complex-foml-

:l

lysts for the last decade because lhey ha"-c extremely hig.h reactivity and catalytic activity in ft.--actions with non-suur
rbL... rchers

and Lherefore arc c'Ktremcly active. The researchers not

mass of the obt3ined polymer ing atom. h is equal to 150 (X)()

only developed the mt.::thod of

"Ole obtained hydrides with the

merization, hydroxylation and

S)'nthesis of the new com· pounds, but aJso studied their catalytic activity in polymeri7..a-

CrHF)2' where Ln is Eu or SOl, rt..'ally contain active hydrogen.

europium.

cycliz:ltion, To dale hydride

tion

For fu.nher information con· tact: Mikhail N.Bochkarev,

compkxes ha\'c been

s~'mhe­

general

formula

LnH 2

of alpha-olefins. They

'111e chemists proved this by

sized almost for all lanthanides

described their resuhs in the

(Ln), but these compounds

paper recenlly published in

studying the reduction of bromine-eontaining compounds.

for sam
e·mail: [email protected].

Toughening at nanoscale makes plastics suitable for aircraft use Tough, heat-fCsistant plastics may soon find their wa}' into car ;Uld :Iircr.lft engines

dissipated Lhe energy of the impact,- $:;I)'S L.::mntllti.

as a reo

particles. TIle silica panicles

resistant plaStiC and reinforced

they use are only 50 nm

with graphite fibre that unCO\"-

Lannutti dC\'eloped the of pro-

wide-about 100 times sma.lJcr than the width of a human hair

cred the need for tougher plas-

suh of research at Ohio Slate Uni\"ersiry. USA. ScientisLS at

ducing these malerials with

and e.lch panicle contains a

the uni\"eristy repon that they

Robert Seghi. associate profL"S-sor of restorative and prosLhet-

host of e\'en smaUer pores that measure only a couple of nano-

ing into an aircraft wing. or even a wrench faJling onto a

ic dentistry at Ohio State, and

metres :Icross.

and Ic.--a\"e behind only ule wo-

have patented a method of mixing plastic with silica [0

tics. lrnpacts Stich as a bird fly-

pan, would shatter the plastic

create a mmerial three to four

graduate srudentJiaz.hong Luo.

times tOugher than the plastic

Their goal, at first. was to

\Vhat m:lkes Lhe patented man-

muti. StiJl. the brittle plastic's

\"en graphite fibr<..-s. S3yS Lan·

:I..Iol1c.

create tough plastic dental fillings. After moderJ.te success

ufacturing method unique is

tolerance of temtxr:uuftS up to -f30°C makes it ideal for

that Lhe resea.rchers force mel-

Plastic engine parts would mean lighter. more fuel-

- they cn.>ated a plastic that was about as good as today's

efficient cars and aircrafts. but today's heat-resistant plas-

standard fillings - L'1nnuni tried the technique with a dif-

tics aren't tOugh enough they

ferem kind of plastic for Ohio

plastic over a large surface area. ~So b:lSiGtUy we can cre-

shatter at the smallest impact,

Aerospace lnstit"ute member BFGoodridl Co. BFGoodrich

ate toughn<..-ss that starts at uu:: nanoscale,- says Uumutti.

says John Lannutti, associate professor of materials science and engineering at Ohio Slate.

ted pl:lStic to fill these tiny

parts

pores. creating a strong bond between atoms of silica and

engines.

supplied plastic powder for

nle new composite material is

Lannuui's experiments, and will manufacture parts cont-

tOugher than plastic alone because it divides the force of an

aining thiS silica for further testing.

impact into many sm311 inter-

surrounding

consumers

jet

In labor:lIor)' t<..-sts, Lhe plasticsilica composite material ret:lim::d the he.lt-re~istance of fibre-reinforced plastiCS. but impro\'ed

Eventually

hot

resistance

10

may

impacts by four to th'e times.

find more pl:lStic parts under their car bonnets. or on a com·

L'1nnutti says the new coml>05itc isn't as hard as steel, bUl

merci:Ll :lircraft wi.ng -

places

displ3yS good he:ll resistance

whcre iron. steel. and alu·

at a fraclion of the weighl of

minum are used today. I..an· nulti adds. Sooner than that,

~tecl.

For further information: John

actions involving millions of

Lannutli and his colh.:agues

individual SiliCI particles. "We

call the mcthod

think thaI as a crack starts Irav-

toughening: or 'toughening across ~cales,' because il

though, military aircraft will probably take advantage of lhe

l"':lIlnutti,

strengthens material down 1O

technology. It was military test-

the scale of the individual

ing of pans made with heat-

versity; tel:+ 1-614-292·3926: c-mail: Lannutti. [email protected]

eling lhrough I hi.: composite, it breaks up into fincr and finer cracks, until the maleria.l has

'~)'ncrgistic

8----------------------------

Ohio

Stale

Materials

Uni-

Today