Viscoelastic behavior of carboxyl-terminated (butadiene-co-acrylonitrile)-based composite propellant binder containing polyglycidyl-type bonding agent

Vis oelasti eha iou of a o l-te i ated utadie e-co-a

lo-it ile - ased o poslo-ite p opella t i de o tai i g

pol gl id l-t pe o di g age t

Saša J. B zić , Go da a S. Ušću lić , Mi ja a V. Di ić , Miloš To ić , Ves a Ž. Rodić , Boja a ). Fida o ski

Milita Te h i al I stitute, Belg ade, Se ia

Fa ult of Te h olog a d Metallu g , U i e sit of Belg ade, Belg ade, Se ia

A st a t

The i flue e of t is , epo p op l iso a u ate as o di g age t o the ph si o he -i al, -is oelast-i a d u -ia -ial te s-ile e ha -i al p ope t-ies of a o l-te -i ated uta-die e- o-a lo it ile u ed ith the pol gl id l ethe of gl e ol a d epi hlo h d i as i estigated. C oss-li k de sit alues e e esti ated s elli g easu e e t. Te pe a-tu e a d f e ue depe de ies of heologi al eha iou pa a ete s sto age odulus, loss odulus, loss fa to a d glass- u e t a sitio te pe atu e e e also a al zed. Based o the f e ue depe de ies of sto age odulus, put i the a ge of te pe atu e f o – to °C the e pe i e t, aste u es log G' s. log ω e e ge e ated,

ea hi g oade f e ue i te al i o pa iso to that used i the easu e e ts. B hoosi g the glass u e t a sitio te pe atu e to e the efe e e o e, Willia s–La -del–Fe e uatio o sta ts e e dete i ed. Fu the , ate ial o sta ts, f a tio al f ee olu e at the glass- u e t a sitio te pe atu e a d the al oeffi ie t of f ee olu e e pa sio e e al ulated. Although s all ua tit of t is , -epo p op l affe ts the

et o k de sit , the d a i e ha i al a al sis sho ed that the o di g age t o te t did ot affe t the glass- u e t a sitio te pe atu e of the tested ate ials.

Ke o ds: a o l-te i ated utadie e-o-a lo it ilе , is oelasti p ope ties, glass– – u e t a sitio te pe atu e.

“CIENTIFIC PAPER

UDC – : . :

He . I d. –

doi: . /HEMIND B

A aila le o li e at the Jou al e site: http:// .a he.o g. s/HI/

The esse tial i g edie ts of a o posite p opella t a e a ossli ked i de a o ga i pol e a d a o idize usuall a o iu pe hlo ate . The i de , as the a e i plies, holds the o positio togethe a d a ts as a au ilia fuel. The use of h d o l-te i al-ted HTPB a d a o l-l-te i al-ted CTPB pol utadie es as p epol e s fo o posite p opel-la ts is the ost o o hoi e of pol e i ate ials to a hie e the desi ed e ha i al p ope ties of the p opella t i o ket oto s [ – ]. I o de to i p o e u ia ial te sile ha a te isti s, a i te a tio et ee the a o iu pe hlo ate AP pa ti les a d the pol

-e i i d-e is -e -essa , hi h is a hi-e -ed o di g age ts added to o posite p opella t o positio . Bo di g age ts a e t pi all used i HTPB ased o -posite p opella ts si e these pol e s a e eakl pola [ ]. Due to the highl pola a o l –COOH g oup, a o l-te i ated p epol e s CTPB do ot e ui e the use of o di g age ts. If fo o posite p opella t p odu tio , a o l-te i ated

Co espo de e: “.J. B zić, Milita Te h i al I stitute, Ratka Resa-o ića , Belg ade, “e ia.

E- ail: sasa zi @g ail. o Pape e ei ed: “epte e , Pape a epted: No e e ,

e e- o-a lo it ile CTBN ased p opella t i de is take , e pe i e ts ha e sho that t is , epo p op l iso a u ate TEIC as o di g age t sig ifi -a tl i p o es u i-a i-al te sile h-a -a te isti s [ ]. The

ole ula st u tu e of the pol e ased o posite p opella t i de is the la gest fa to i dete i i g the e ha i al p ope ties of the i ed a d u ed p pella t. The e ha i al p ope ties of o posite p o-pella ts depe d st o gl o the ti e, te pe atu e, loadi g p o edu e a d loadi g histo [ ]. “i e the o di g age t is i g edie t that is added to odif the e ha i al p ope ties of the p opella t, p e ise k o ledge of the d a i e ha i al eha iou is e t e -el i po ta t.

The ai o je ti e of this pape is to oade ou k o ledge of appl i g d a i e ha i al a al sis to the stud of CTBN- ased p opella t i de . As fa as e a e a a e, the e a e o pu li atio s i the e te -si e lite atu e, e ept ou p e ious i estigatio , that ha e su e ed ot o l the is oelasti p ope ties of CTBN- ased o posite p opella t i de ut also the effe t of this t pe of o di g age t o the CTBN- ased

EXPERIMENTAL Mate ials

Fou CTBN ased o posite p opella t i de o -positio s Ta le sele ted fo this stud o sisted of

ph of CTBN × , BF Good i h, is osit at °C: . Pa s, a o l fu tio alit : . , u e a e -age ole ula eight: g/ ol, spe ifi g a it at °C: . g/ , glass-li uid t a sitio te pe atu e, Tg: – . °C , . ph of a tio ida t , '- eth le - is - - eth l- -te t ut l phe ol , o e iall a aila le as a p odu t alled AO a d u de a lot of othe a d a es Fluka AG, “ itze la d a d . ph of u e atal st i o III -a et la eto ate, Fe a a , Me k-“ hu ha dt, Ge a . Mi atio of p opella t i de i g edie ts is e p essed i ph , this ea s pa ts pe hu d ed of esi ased o pa ts of CTBN.

P efe ed u i g age ts fo a o l fu tio al p e-pol e s a e ultifu tio al epo ides. Whe epo

u i g age ts a e used to u e a a o fu tio al p epol e i o posite p opella t fo ulatio , the E/COOH atio et ee the t o o po e ts is p e-fe a l i the a ge of f o . to a out . . P ese e of a o iu pe hlo ate as o idize , auses side ea tio s i ludi g the u i g age t. As a esult, less o plete pol e et o k is fo ed. The E/COOH atio et ee the epo g oups E of the u i g age t to the a o l g oups COOH of the CTBN as . . The u i g of CTBN as a hie ed a epo id u i g usi g LX pol gl id l ethe of gl e ol a d

epi-hlo h d i , EW: , Ladd Resea h I dust ies, U“A . The he i al st u tu es of the p opella t i g e-die ts a e sho i Figu e .

T is , -epo p op l iso a u ate as p epa ed the ea tio of a u i a id a d epi hlo h d i i

a o da e ith a odified lite atu e ethod [ ]. I -estigated o posite p opella t i de sa ples diffe f o ea h othe i o di g age t o te t. Co posi-tio CPB is a aseli e p opella t i de o posiposi-tio

o tai i g o o di g age t. TEIC o te t ξ a ied f o . to . t.% of the total ass of the i es-tigated p opella t i de .

Methods

Mi i g of p opella t i de fo ulatio s as o -du ted i a . l DRAI“ FH pla eta i e at a te pe-atu e of °C. CTBN, AO a d TEIC e e le ded tho oughl fo i at a ie t p essu e a d the a uu i ed fo a othe i . LX as the added to the i tu e, i ed fo i utes at a ie t p essu e a d the a uu i ed fo a othe i . The , Fe a a as added to the i tu e a d the sa e p o edu e as epeated. Fi all , the p epa ed i tu e as ast a d u ed i teflo - oated etal plates to fo thi k sla s. The u i g as pe fo ed fo da s at °C.

The et o k de sit of a u ed p opella t i de sa ples as esti ated the deg ee of s elli g a app op iate sol e t at e uili iu [ ]. As sol e t, tol-ue as used. The g a i et i te h i tol-ue as applied fo easu i g the s ell atio of ossli ked p opella t i de et o ks. “ elli g test as a ied out o e -ta gula spe i e s ith le gth of , idth of

a d thi k ess of at the T = °C. I p e-li i a e pe i e ts, the sa ple as allo ed to s ell fo da s, ut ass e a e o sta t afte t o da s, i di ati g that e uili iu as ea hed. The efo e tested i de sa ples e e s elled fo t o da s.

“ ell atio is o puted as:

Ta le . I estigated p opella t i de o positio s, ph t.% of the total ass of the tested p opella t i de

“a ple P opella t i de

CTBN LX TEIC AO Fe a a

CPB . . . . . . .

CPB . . . . . . . .

CPB . . . . . . . .

CPB . . . . . . . .

HOOC CH2 CH CH CH2n CH2 CH

C N

mCOOH

CH2

H2C CH

O

C N

C N

C N

O

O O

CH2 CH CH2

O

CH₂ CH CH₂

O

a Ca o l-te i ated utadie e- o-a lo it ile CTBN T is , -epo p op l iso a u ate TEIC

d g d d

W W W K W

+ −

=

he e: Wd – sa ple eight efo e i e sed i tolue , Wg – sa ple eight afte t o da s i tolue a d K –

atio of the de sities of the sol e t to the pol e . The de sit of tolue e is . g/ , a d those of u ed p opella t i de sa ples e e i the a ge f o . to . g/ , easu ed follo i g A

hi-edes p i iple [ ].

The alue of et o k de sit , N, of the i de sa ples as esti ated the alue of usi g the Flo –Reh e e uatio , E . :

l −ν +ν +χν = −NV ν −ν

he e: ν – olu e f a tio of the i de i the s olle gel, χ – Flo –Huggi s pol e –sol e t i te a tio pa a ete , V – ola olu e of the sol e t, N – et-o k de sit et-of the tested i de sa ple. The alue et-of Flo –Huggi s pol e -sol e t i te a tio pa a ete χ take fo pol utadie e-tolue e s ste a d the alue of ola olu e V of s elli g sol e t a e: . a d · ol–_{, espe ti el [ ].}

The DMA easu e e ts e e a ied out i the to sio defo atio ode usi g a e ha i al spe -t o e-te odel RM“- a ufa tu ed the fo e Rheolog Busi ess U it of o pa Rheo et i “ ie tifi I ., Pis ata a , NJ, U“A. The te pe atu e a ge applied as f o – to °C, the heati g ate as °C i – _{a d the si gle f e ue poi t of Hz} as hose . “t ai a plitude as . %. The sa ples fo DMA tests e e of e ta gula a shape

× × – . Co ple shea odulus as dete i ed, G* ω = G'ω + iG''ω. E t a ted data e e the shea sto age a d loss oduli, G' a d G'', espe ti el , a d the loss fa to ta = G''/G'. Ea h

i de sa ple as fi st tested at a o sta t f e ue a d te pe atu e o e a o e e tio ed a ge.

The te pe atu e o espo di g to the a i u of the loss fa to is take as the o i al glass t a sitio te pe atu e, o e tl a ed as glass– u e t a -sitio te pe atu e Tg [ ]. Fi all , the is oelasti p ope ties e e easu ed o e th ee de ades of f

e-ue i the te pe atu e a ge f o – to °C, s a ed ith a heati g ate of °C i –_.

F e ue as a ied f o . to ad/s, ith e uidista t alues o a loga ith i s ale. The easu

e-e t e-ep odu i ilit is e-e high so o l o e-e sa ple-e pe ea h testi g o ditio as tested [ ].

D“C a al ses, i o de to i estigate the the all ased glass– u e t a sitio te pe atu e of the sa ples, e e a ied out usi g the D“C Q a ufa -tu ed TA I st u e ts ith li uid it oge ooli g fo lo te pe atu es. The te pe atu e s ale as ali

-ated usi g the elti g te pe atu e of high pu it i diu . The s all a ou t of the sa ple ∼ g as s a ed ith a heati g ate of °C i –, sta ti g f o – °C a d e di g at °C. The glass– u e t a sitio te pe atu e of the sa ple as dete i ed f o the idpoi t of the t a sitio .

The u ia ial te sile e ha i al p ope ties of the i estigated sa ples e e e aluated at °C usi g IN“TRON u ia ial te sile test a hi e fitted ith a N load ell. “ all dog o e sa ples

le gth, idth a d thi k ess e e used. C osshead speed of te sile a hi e as / i , hile the effe ti e gauge le gth of the test sa ples as . .

RESULTS AND DISCUSSION

Net o k de sit of p opella t i de sa ples

“i e the s olle i de sa ple is e tou hse -siti e a d p o e to a ki g, the g a i et i te h i ue is used fo easu i g the s ell atio of oss-li ked p opella t i de et o k. Results of the a al sis Ta le sho that ith the i ease of TEIC o te t, the oss-li k de sit of the i estigated i de sa ples i ease also. The highest N alue is o se ed fo CPB . ass% of TEIC i de sa ple. We o

-lude that the oss-li k de sit of a pol e et o k a ot e dete i ed defi itel usi g this ethod alo e. Gel f a tio , as a esult of sol-gel a al sis ould e i po ta t additio al ole ula pa a ete he p edi tio of oss-li k de sit of a pol e et o k is o te plated. Ho e e , the i ease i N alue sug-gests that the deg ee of oss-li ki g should i ease.

Ta le . Values fo et o k de sit N a d olu e f a tio of i de i s olle gel νof p opella t i de sa ples

dete i ed s elli g tests.

Pa a ete “a ple

CPB CPB CPB CPB

ξ / ass% . . .

ν . . . .

N× – / ol· – . . . .

The i ease of the et o k de sit alue poi ts to the fa t that the fu tio al epo g oups of TEIC a e i ol ed i the p opella t i de et o k fo atio .

D a i e ha i al a al sis of o posite p opella t i de sa ples

It follo s f o Figu e that the G' is al ost o s-ta t at lo te pe atu es a d it ea hes the a i u

alue i the egio elo the glass t a sitio – to – °C . The t a sitio f o the glass to the u e state the o set poi t o the G'–T u e at T = – °C has as o se ue e a d op i the G' alue a fa to of a out f o MPa at – °C to . MPa at – °C . With i easi g te pe atu e et ee T = – °C a d T = °C the G' u e e hi its a t ostep ha -a te , i di -ati e of t o sep-a -ate el-a -atio p o esses. “i ila te pe atu e depe de e of G' u e as o s-e s-ed i ths-e CTBN- ass-ed o posits-e p ops-ella t o positio ha i g AP [ ]. Thus, the e iste e of t o ela -atio p o ess o se ed i the o posite p opella t

o positio ould ot e att i uted o l to the i f-lue e of AP solid pa ti les o the pol e et o k

o ilit . Copol e s ofte sho a oade i g of the t a sitio egio ith a de ease i the slope of the odulus u e. Pa t of oade i g of the t a sitio egio ould e due to the hete oge eit i the ole-ula eight et ee oss-li ks. Also, the easo fo slo de ease of the sto age odulus ould e s-talli it ithi a pol e st u tu e of tested p opella t

i de sa ples [ ].

The glass– u e t a sitio te pe atu e Tg of elasto e o ded o posite p opella t is o e of the ost i po ta t p ope t dete i i g thei i -se i e appli atio [ ]. This ea s that the Tg alue of the o posite p opella t i de ust e lo e tha the i i u se i e te pe atu e usuall – to – °C depe di g o appli atio .

A ole ula i te p etatio of the is oelasti eha io a e gi e o side i g the ta , hi h des i es ole ula ea a ge e t egio s, o es-po di g to the i de f a tio s ith diffe e t o ilit . Pol utadie e - ased elasto e s o tai soft a d igid seg e ts [ ]. The soft seg e ts o sist of la ge fle i le o - stalli e pol e hai s, i this ase, pol utadie e , hile igid ha d seg e ts o sist of

oss-li ki g u its.

The peak of ta positio ed et ee T = – °C a d T = – °C its te pe atu e lo atio is desig ated as Tg, is att i uted to the glass– u e t a sitio te -pe atu e Ta le . This ela atio p o ess i ol es

eo ie tatio al otio s of p epol e CTBN ai hai s et ee the ossli ks ithi the soft seg e t egio s. These pol e et o k seg e ts ha e e lo de sit of este g oups a d a e the pol utadie e

-100 -80 -60 -40 -20 0

20 40 60 80

10

10

10

10

10

10

T_G''

G'(25 oC)=271.3 kPa tanδ_max=0.76

tanδ(-91 oC)=0.02 T_G'

G''(-60 oC)=57.8 MPa

G', G'' [

Pa]

T [

_C]

G

'

G

''

G'(-91 oC)=573 MPa

T g1

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

1,6

tan

(

δ

)

tan

(

δ

)

Figu e .Cha a te isti alues of the CPB aseli e o positio sho the DMA the og a of ω = . ad s– _{= Hz.}

Ta le . ta a alues a d Tg °C alues dete i ed G'', G', ta a d f o DSC u es

“a ple Tg / °C Ma i u alue of _ta

a

T i a of G'' Ta ge s ethod ith G' T i a . of ta δ D“C at °C/ i

CPB – . – . – . – . .

CPB – . – . – . – . .

CPB – . – . – . – . .

pa t of i de hi h eo ie t at e lo te pe atu es. The Tg alue fo the aseli e o positio , CPB , is – . °C.

The peaks, that appea at highe te pe atu es, et ee – a d °C, o espo d to the ela atio p o ess elated to the otio s ithi ha d seg e t u its. Ha d seg e ts ould also o tai pol e i hai s fo ed the ea tio of se o da h d o l g oups a d epo g oups [ ] Figu e . Ho e e , the pa ts of ta a o e see so e hat s atte ed i data, so i te p etatio is diffi ult to gi e.

The Figu e sho s te pe atu e depe de ies of the sto age odulus, G', loss odulus, G'' a d the loss fa to , ta of the o posite p opella t i de sa ples. CPB i de sa ple . % TEIC has the lo

-est alues of G' i the plateau of glass state. Modulus i the glass state is dete i ed p i a il the st e gth of the i te ole ula fo es a d the a the pol e hai s is pa ked [ ]. The i ease i sto age odulus alues ith i easi g TEIC o te t suggests that a toughe , o e igid et o k is o tai ed at highe TEIC o e t atio s. The esults a e o siste t ith s elli g easu e e ts hi h i di ate a i ease i the ossli k de sit ith i t odu tio TEIC i i de sa ples.

Fo the p opella t i de sa ples o l uite s all a iatio s i Тg e e o se ed, despite the ha ges i effe ti e ossli k de sit as e ide t i the sto age odulus alues. The easo is the o e t atio of oss-li k poi ts apa t f o the pol utadie e pa ts, hi h a e espo si le fo the ai glass u e t a -sitio at lo te pe atu es.

Fo all i de sa ples, ega dless the TEIC o te t, Tg alues a e lo ated i the a o te pe atu e a ge

Тg ≈ – °C .

Nu e ous studies i di ate that the est i ted o -ilit a d the hete oge eit of the pol e s ste a ise f o the p ese e of oss-li k ithi the pol e et o k [ ]. C osli ks a e leadi g to a ds the de -ease i u e of possi le o fo atio al otio s, i.e., o fo atio al f eedo of pol e hai

seg-e ts, seg-esulti g i li itseg-ed o ilit seg-egio s a ou d thseg-e ossli k poi ts. It is also sig ifi a t to o side the i flue e of ossli k de sit o the glass u e t a -sitio te pe atu e po-sitio .

E t e el high ossli k de sit alues shift the glass– u e t a sitio to a d highe te pe atu es. Glass– u e t a sitio te pe atu es, dete i ed D“C Figu e a d Ta le , a e lo e tha the o es dete i ed DMA. The easo is the stati dete

-i at-io , h-i h ea s o e ha -i al defo at-io ausi g st ai ha de i g is applied, egle ti g the olu e ha ge the al e pa sio [ ].

The i a ia e i Тg alues, ega dless of the ethod of dete i i g, i di ates that dista es et ee the ossli k poi ts ithi the pol e et o k of tested i de sa ples a e su h that the est i tio s affe ted the p ese e of the o di g age t du i g the ossli k p o ess do ot o t i ute to diffe e es i Тg alue. I othe o ds, oope ati e eo ie tatio al otio s of pol e et o k seg e ts, elated to ai

COOCH₂ CHCH₂

OCH₂ CHCH₂ OH

COOCH₂ CHCH₂

OH

CH₂ CHCH₂ O

+

Figu e .The ea tio of the epo g oup of o di g age t TEIC a d the se o da h d o l g oup of the i de s ste fo ed the u i g ea tio et ee CTBN a d the epo - ased u i g age t.

-100 -80 -60 -40 -20 0 20 40 60 80

105 106 107 108 109 104 105 106 107 108 0,0 0,2 0,4 0,6 0,8

c)

G'' [Pa

]

G' [

Pa]

T [o_C]

CPB00 CPB01 CPB02 CPB03

b)

tan

(

δ)

a)

ela atio t a sitio a e ot i flue ed. The o es-po di g ela atio ti e is o l ha ged i o the st u tu al ha ges i i de oss-li k st u tu e due to TEIC additio .

I Ta le a e sho the i te sit of Тg, ta a , alues o the loss fa to u e fo the tested p opella t i de s. The ta a alue is i flue ed the

seg-e tal otio of thseg-e pol seg-e hai s. Thseg-e lo seg-e thseg-e o ilit est i tio s o the pol e hai s a e, the highe the ta a alues. Although the ta a de ease ith additio of . t.% of TEIC, fu the i ease o di g age t o te t sig ifi a tl i ease this alue. The a i u as e o ded fo the CPB p opella t i de sa ple. This a e e plai ed i hi itio of the hai seg e t ela atio p o esses o a i ease i the igidit of the hai seg e ts, i easi g the p opella t pol e et o k hete o-ge eit .

F e ue depe de e of o posite p opella t i de sa ples

Figu e sho s the f e ue depe de es of G' of p opella t i de sa ples. “to age odulus i eases i a egula fashio ith i easi g f e ue o de

-easi g te pe atu e, suggesti g that ti e-te pe atu e supe positio of the data is possi le. “i ila esults e e o tai ed fo ea h of the fou p opella t i de sa ples.

The sto age odulus e sus te pe atu e u es at a ious f e ue ies e e shifted usi g the ti e–te -pe atu e su-pe positio p i iple tT“P , ased o the asu ptio of the e ui ale e loadi g i te pe atu e a d ti e [ ]. The a ou t of shifti g alo g the ho -izo tal -a is of ea h u e to alig ith the efe e e te pe atu e u e is ge e all des i ed the

Wil-lia s–La del–Fe WLF e uatio [ ], hi h defi es the shift fa to aT, i depe de e of the te pe atu e

ha ge:

(

)

o

log T

C T T a T

C T T

− −

=

+ −

The s ols a e: aT – shift fa to ep ese ti g the atio et ee the ti e eeded fo so e phe o e o to e de eloped at e tai te pe atu e T a d the ti e fo the sa e phe o e o at efe e e te pe atu e, T – test te pe atu e, То – efe e e te pe atu e, C, C – WLF o sta ts, hi h depe d o the efe e e te -pe atu e. The autho s of the WLF e uatio fou d that fo a a o phous pol e s, i depe de t of he -i al st u tu e a d -ith the glass t a s-it-io te pe atu e as efe e e te pe atu e, the t o o sta ts C a d C ha e u i e sal alues of . a d . °C, espe t el . But su el this is a ough app o i atio . Fo o e a u ate al ulatio s it is e essa to dete i e the alues of a shift fa to aT, a d o sta ts C a d C fo ea h ate ial i o side atio .

The aste u e efe e e te pe atu e as To = = – °C. I p a ti e, it is est to hoose a efe e e te pe atu e at the idpoi t of the data a d supe pose the data to this te pe atu e [ ]. Figu e sho s se -e al i po ta t f-eatu -es o -e i g th-e is o-elasti - es-po se of the p opella t i de sa ples. G' ea hes the

a i u at lo te pe atu es high f e ue ies . At highe te pe atu es lo e f e ue ies G' u es e te the u e plateau. Maste u es of the i de sa ples sho a g adual slope i t a sitio egio . “to age odulus ha ge alo g ith the st ai ate ha ge is s all, i di ati g these ate ials a e al ost i se siti e to the st ai ate, i.e., te pe atu e. The i flue e of

efe e e te pe atu e's hoi e o aste u e's posi-tio a d shape of sto age odulus f e ue depe -de e fo a i -de sa ple CPB is sho i Figu e .

It is otified that, ega dless of the efe e e te -pe atu e, aste u es a e of the sa e sha-pe, ut the

u e ep ese ti g highe efe e e te pe atu e is shifted to the highe f e ue . The te pe atu e dep-e ddep-e of shift fa to aT alues fo all i de sa ples is sho i Ta le .

F o the elatio et ee WLF e uatio o sta ts o tai ed ith t o efe e e te pe atu es the elatio gi e i E s. a d a e o tai ed. I o e ase, the glass– u e t a sitio te pe atu e Tg is efe e e, a d i the othe ase the efe e e te pe atu e is

a ed Tо.

,g

g o

C C C

C T T

=

+ −

,g g o

C =C +T T−

Fu the o , et ee the t o sets of o sta ts the E . is alid a d E . esults f o a o e:

,g ,g

C C =C C

g ,g o i f

T C− =T C− =T

Ti f is the te pe atu e at hi h, ega dless the a Tо is sele ted, the log aT T alue e o es i fi ite a o di g to WLF e uatio , see E . . Ph si all , it is the te pe atu e at hi h oope ati e otio s of pol

-e -et o k s-eg -e ts app-ea at i fi it-el s all d-ef- def-o atidef-o f e ue ies, ei g p e idef-ousl est i ted at glass– u e t a sitio te pe atu e. The WLF e uatio fo ulated ith Tg as efe e e is gi e i E . :

-6 -4 -2 0 2 4 6 8

4 5 6 7 8 lo g10 [G'(T 0 /T) (Pa)] 293K

log₁₀[ωa_T(rads-1)]

lo

g 10

[G' (Pa)]

log₁₀[ω(rads-1)] 223K

CPB00

-6 -4 -2 0 2 4 6 8

4 5 6 7 8

log₁₀G' log10G'(T0/T)

-6 -4 -2 0 2 4 6 8

4 5 6 7 8 lo g10 [G'(T 0 /T) (Pa)] 293K

log₁₀[ωa_T(rads-1)]

lo

g10

[G' (Pa)]

log₁₀[ω(rads-1)] 223K

-6 -4 -2 0 2 4 6 8

4 5 6 7 8

log₁₀G' log₁₀G'(T₀/T)

CPB01

-6 -4 -2 0 2 4 6 8

4 5 6 7 8 lo g 10 [G'(T 0 /T) (Pa)] 293 K

log₁₀[ωa_T(rads-1)]

lo

g10

[G'

(Pa)]

log₁₀[ω(rads-1)] 223 K

-6 -4 -2 0 2 4 6 8

4 5 6 7 8 CPB02

log₁₀G' log₁₀G'(T₀/T)

-6 -4 -2 0 2 4 6 8

4 5 6 7 8 log10 [G'(T 0 /T) (Pa)] 293K

log₁₀[ωa_T(rads-1)]

lo g10 [G' (P a) ]

log₁₀[ω(rads-1)] 223K

CPB03

-6 -4 -2 0 2 4 6 8

4 5 6 7 8

log₁₀G' log₁₀G'(T₀/T)

(

)

,g g

,g g

loga T_T C T T

C T T

− −

=

+ −

“i e the WLF e uatio is ased o the f ee olu e o ept, the follo i g elatio s a e de i ed [ ]:

,g

g

. B C

f =

g ,g

f

f C

α

=

he e: B is a o sta t i the Doolittle e uatio , hi h is assu ed e ual to u it , fg is the f a tio al f ee olu e of the elasto e at the Tg a d αf is the the al oeffi ie t of e pa sio of the f ee olu e a o e Tg.

Ta le p ese ts the WLF a d f ee olu e o s-ta ts fo the i estigated i de sa ples.

O tai ed esults o fi that WLF e uatio o s-ta ts C,g a d C,g, a e ot u i e sal , ut oughl app o i ated the u i e sal alues. If u i e sal o sta ts a e used, sig ifi a t istakes ould e ade fo esti ati g ho o posite p opella t eha es at diffe e t te pe atu es a d st ai ates. A o di g to lite atu e data, the e a e ode ate de iatio s f o the gi e C,g alue depe di g o the pol e t pe, hile

ith o sta t C,g de iatio s a e la ge [ ]. This also applies to ou i de sa ples. αf/B alues a e lo e tha the o e de i ed f o WLF e uatio . O tai ed fg/B

alues a e ithi the ou da ies fou d i lite atu e fo ost of pol e s ste s.

U ia ial te sile p ope ties of p opella t i de sa ples

The a e age a d sta da d de iatio “D alues of u ia ial te sile e ha i al p ope ties, i.e., the te sile st e gth σ , the st ai at a i u load a d You g's odulus Е fo the i estigated i de sa ples a e listed i Ta le .

All of the alues listed i Ta le e e o tai ed as a a e age of fi e spe i e s. The u ia ial te sile p pe ties of o posite p opella t depe d o te sile p o-pe ties of p oo-pella t i de , hi h i tu dete i es the st ai apa ilit of the p opella t. High st ai ap-a ilit of i de et o k is fap-a ou ap-a le o side i g lo g shelf life of p opella t s ste [ ]. The alue of the st ai at a i u load of the aseli e o positio , p i a il aused the p epol e CTBN ole ula eight, is . %, hi h is uite a epta le alue o pa e to that of othe ate ials used fo o posite p opella t a ufa tu e. CTBN- ased o posite p o-pella t i de gi es u h highe alue of the st ai at

-10 -8 -6 -4 -2 0 2 4 6 8

4 5 6 7 8 9

CPB00

log[

G'

To

/T

(Pa

)]

log [ωa_T (rads-1)]

T ref=- 20

o_C

T

ref=Tg

Figu e . Maste u es of sto age odulus G' fo the sa ple CPB sho fo t o efe e t te pe atu es, Тef = Тg a d Тef = Тo = – °C.

Ta le . E pe i e tal alues of WLF e uatio a d f ee olu e o sta ts

“a ple C C / °C C,g C,g / °C Ti f, / °C fg/B× - αf/B× - / K–

U i e sala _{– – . . – . .}

CPB . . . . – . . .

CPB . . . . – . . .

CPB . . . . – . . .

CPB . . . . – . . .

a i u load o pa e to the HTPB- ased o e, hi h a ha e the alue hi h does ot e eed %. Additio of . t.% TEIC i CTBN ased p opella t i de i eases all u ia ial te sile p ope ties. O o e ha d, i easi g the te sile st e gth a d You g's odulus is aused la ge a ou t of ha d seg e ts. O the othe ha d, the i o po atio of TEIC i to the p opella t i de fo ulatio i eases the alue of st ai at a i u load as a o se ue e of the i

-eased ole ula eight of the pol e hai s et ee the ossli k poi ts. TEIC at . t.% auses a i ease i te sile st e gth of . % ith a si ulta eous i

-ease i the st ai at a i u load alue of . %. Fu the i ease of TEIC o te t esulted i a slight de ease of alues of all u ia ial te sile ha a te isti s.

CONCLUSIONS

“a ples of o posite p opella t i de ased o a o l-te i ated utadie e- o-a lo it ilе u ed ith pol gl id l ethe of gl e ol a d epi hlo h d i LX- o tai i g the o di g age t t is , epo -p o-p l iso a u ate TEIC e e i estigated ith D“C, DMA a d u ia ial te sile testi g. Although the et o k de sit i eased ith additio of TEIC, the te

pe-atu e depe de es of heologi al pa a ete s e eal that the glass- u e t a sitio te pe atu e of the i estigated p opella t i de s does ot ha ge the additio of t is , -epo p op l iso a u ate. The glass– u e t a sitio te pe atu e, Tg, of all p opel-la t i de s as a out – °C dete i ed as a i u te pe atu e of ta ith DMA at Hz defo atio f e ue . Co side i g the te pe atu e depe de ies of ta the flu tuatio eha io a ou d a sto age te pe atu e is o se ed.

Ti e–te pe atu e supe positio as used to o s-t u s-t odulus-f e ue aste u es that ha e ee ge e ated fo the te pe atu e a ge f o – to °C o side i g the u e at – °C as efe e e. The e pe-i e tal f e ue a ge of th ee loga ith i de ades

easu ed et ee – to °C, is e te ded to te loga ith i de ades. B hoosi g the glass u e t a -sitio te pe atu e of tested i de sa ples to e the

efe e e te pe atu e i WLF e uatio a d ased o C a d C o sta ts alues at efe e e te pe atu e of – °C of the sa e e uatio , ot o l the alues of

u i e sal o sta ts C,g a d C,g ha e ee al ulated, ut also the f a tio al f ee olu e at the glass- u e t a sitio te pe atu e a d the the al oeffi ie t of f ee olu e e pa sio . The fo e is i ag ee e t, hile the latte is lo e tha the lite atu e data. Due to the e ui e e ts du i g i se i e appli atio s, o posite p opella t i de s ith lo glass u e t a -sitio a d e tai st ess–st ai apa ilities a e desi ed. Of the a ious o posite p opella t i de p ope ties, o e has ee o e diffi ult to a hie e tha the lo te pe atu e e ui e e ts. It has ee so diffi ult to fi d o posite p opella t i de that eet the – °C goal. Based o sho test esults, o side i g the fa t that this t pe of p epol e is o e iall a aila le, it a e stated that CTBN ould e su essfull used as o posite p opella t p epol e . Mo e spe ifi , Tg alues a out – °C , o side ed togethe ith fa o -a le -alues of the st -ai -at -a i u lo-ad, uite justif the use of the CTBN as p epol e fo ase- o ded

o posite p opella t g ai p odu tio .

I o de to a hie e highe alues of u ia ial te sile ha a te isti s, it is a epta le to i t odu e TEIC as o di g age t ithi the i de o positio i a ou ts ot highe tha . %.

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Ma ufa tu e, Haza ds a d Testi g, A e i a Che i al “o iet , Washi gto , DC, , Vol. , pp. – . [ ] B.K. Biha i, W.“. Wa i, N.P.N. Rao, P.P. “i gh, B.

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Ta le : Values of te sile st e gth σ , st ai at a i u load a d You g's odulus Е o u ia ial te sile test of CTBN ased p opella t i de sa ples at T = °C. SD: sta da d de iatio , ξ: TEIC o te t of the total ass of the i estigated p opella t

i de

“a ple ξ / t.% σ SD / MPa SD / % Е SD / MPa

CPB . . . .

CPB . . . .

CPB . . . .

Fille o the Rela atio P o esses, J. Appl. Pol . “ i. – .

[ ] H. P i e, U“ pate t .

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[ ] T. “e idoglu, M.A. Boh , Effe t of u i g age ts a d plasti ize s o the loss fa to u es of HTPB– i de s ua tified odelli g, i P o eedi gs of the th

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I)VOD

VISKOELASTIČNO PONAŠANJE VE)IVA KOMPO)ITNOG RAKETNOG GORIVA NA BA)I KARBOKSI-TERMINIRANOG BUTADIEN-CO-AKRILONITRIL KOPOLIMERA SA VE)UJUĆIM AGENSOM POLIGLICIDILNOG TIPA

“aša B zić , Go da a Ušću lić , Mi ja a Di ić , Miloš To ić , Ves a Ž. Rodić , Boja a ). Fida o ski Voj oteh ički I stitut, Ratka Resa o ića , Beog ad, S ija

Teh ološko– etalu ški fakultet, U i e zitet u Beog adu, Ka egije a , Beog ad, S ija

Nauč i ad

U adu je ispita uti aj t is , -epoksip opil -izo ija u ata kao ezujućeg age sa a fizičko–he ijske, iskoelastič e i jed oos e eha ičke ka akte istike ka oksi-te i i a og kopoli e a utadie -o-ak ilo it il u eže og sa poli-gli idil et o poli-gli e ola i epihlo hid i a. V ed osti gusti e u eže osti od eđe e su etodo u e ja. А alizi a e su te pe atu e i f ek e io e za is osti pa a eta a eološkog po aša ja odula saču a e G' i izgu lje e e e gije G'' , ta ge sa ugla gu itaka, ta , kao i te pe atu e ostaklji a ja, Тg. Na os o u

ed osti f ek e io ih za is osti odula saču a e e e gije, ekspe i e tal o od eđe ih u te pe atu o opsegu od – do °C, ko st uisa e su z i e

aste k i e, koje p ek i aju z at o ši i i te al f ek e ija loga ita skih dekada u od osu a o aj u ko e je še o e e je. Oda i o te pe atu e ostaklji a ja kao efe e t e te pe atu e, od eđe e su u i e zal e ko sta te WLF jed ači e, a os o u kojih su iz aču ate ed osti pa ijal e slo od e zap

e-i e a te pe atu e-i ostaklje-i a ja, fg/B, i koefi ije t toplot og ši e ja slo od e

zap e i e, αf/B. Iako ale količi e t is , -epoksip opil -izo ija u ata utiču a

gusti u u eže osti, ezultati di a ičke eha ičke a alize pokazuju da sad žaj o og ezujućeg age sa e utiče a te pe atu u ostaklji a ja ispiti a ih sasta a

ezi a.

Ključ e eči: Ka oksi-te i i a i kopoli-e utadikopoli-e - o-ak ilo it il •

Visoko-elastič a s ojst a •Te pe atu a