Carbon Science Vol. 6, No. 3 September 2005 pp. 173-180 Densification of 4D Carbon Fiber Performs with Mesophase Pitch as Matrix-Precursor Hyeok-Jong Joo and Jae-Won Lee Dept. of polymer science & Engineering, Chungnam National University, Daejeon 305-764, Korea Ì e-mail: Joohj@cnu.ac.kr (Received May 27, 2005; Accepted September 2, 2005) Abstract In this study, AR (aromatic resin) pitch was employed as the matrix-precursor for carbon/carbon composite because it exhibits much higher coke yield than coal tar pitch. As a result, a fabrication process of carbon/carbon composites can be shortened. It has been known that the pitches may cause swolling problem during the carbonization process. In order to restrain the swelling occurrence, a small quantity of carbon black was added to the AR pitch. Due to addition of carbon black the swelling was decreased largely and the perform can be infiltrated with the AR pitch. The densification efficiency of the performs was compared with various matrix-precursors. The coke yield of matrixprecursors, the morphology and the degree of graphitization of carbon matrix were analyzed. Keywords : Mosophase pitch, Carbon/carbon composite, Densification of carbon material, Pressure carbonization 1. nt o lp rm 3000 o C p p m v n p ol,, r, kr p e q n p. ˆ /ˆ q 2500 o C p p ml ml p m p ov, n lr m p lž} p l r p ˆo [1-4]. p q p, ntm p nose conep leading edge p q pe ll vr d p p, mn turbine wheel, l p l~, oq p l, Î n m mold ~mp p n l hip jointm p ~q pn p [5-11]. ˆ /ˆ qp v t v p l vm p v precursor n. ˆ r tl ˆ pnp o p r, p p e ˆ pp p v precursor ˆ l p ˆ v }otlk. q n l} k l np p ~ p l l n, q p, s, t q k ˆ pp d p r, k ˆ e 90% p p ˆ pp lp p p pp, l np qrp v p [12, 13]. ˆ /ˆ q rp l p, ˆ, l rp ~k l q p l v n, qe p Œqm p rr p kp. l l ˆ p super acid catalyst(hf/bf 3 ) p n l t l oligomer lp l} l ˆ rs Mitsubishi Gas Chemical p AR(aromatic resins) v precursor r m. p ˆ / ˆ q rs o p r m p ˆ pp p pl rp eˆ p p. p p p ˆ o (preform)p rp q n m. ˆ rtl AR p p p pl r p l np p p o p ~ l AR v l r ˆ o p rp p v precursor rs m. rl rn l} k p r 10 MPa p l k rp nml rrp q m. 2. x 4D(4, 4 directional) ˆ /ˆ q rs o l n o ˆ lìp PAN o
174 H.-J. Joo and J.-W. Lee / Carbon Science Vol. 6, No. 3 (2005) 173-180 Table 1. Properties of carbon fiber used for the fabrication of 4D carbon/carbon composites Fiber type Filament count Diameter T.S. (Mpa) T.M. (Gpa) U.E. (%) Yield (g/1000m) T.C. (Kcal/mh o C) C.T.E. (1/ o C) Density (g/cm 3 ) High strength 12,000 6.85 3528 245 1.3 800 15 0.1 10 6 1.80 Table 2. Typical properties of AR pitch Physical properties Appearance Black pellet (D: 3 mm, L: 7 mm) Bulk Density (g/cm 3 ) > 0.65 Specific Gravity (25 o C) 1.23 Specific Heat (cal/g/ o C) 0.65 Softening Point ( o C) by Mettler 275 Mesophase Content (%) 100 Hydrogen/Carbon (atom/atom) 0.58-0.64 Flash Point ( o C) > 300 Ash (ppm) < 20 (TZ-307) p Table 1. 4D ˆ /ˆ qp o n q Mitsubishi Gas Chemical l t AR(aromatic resins) oligomer l} l lp AR n. AR 100% s pdp p p p Table 2m. k rl AR p r o r n ˆ Ìp ˆ ~ r n mp s p Table 3. AR p p p rl o p ~ r n m. p rp n p p s pp, s l p p rp l} e Žo lr. DBP, v dibutyl phthalate p Žop lr n p ˆ. l DBP p p p l s kk o p. e l AKZO NOBEL l Ketjen black EC 600JD n mp Table 4l p p p ˆ. x pp p o rp m r o v precursor n AR p m l npr r r r 400 o C l ˆ p k 300cPp r m. r r m p s Table 4. Analytical properties of ketjen black (EC 600JD) Analytical properties Iodine Absorption (mg/g) 1050 DBP (ml/100 g) 495 Surface Area [BET] (m 2 /g) 1270 Volatiles (%) 0.7 PH 9.0 Calcium Carbonate Content (%) 0.1 Average Diameter (nm) 30 Residue at Sieve (ppm, 325 mesh) 15 Specific Gravity (g/l) 115 Metal Content Ni (ppm) 2 V (ppm) > 1 Fe (ppm) 90 Cu (ppm) > 1 Mn (ppm) > 1 ˆ. p r o vpp 50%p l l p r l AR l r p(l r 114.7 o C) ˆˆ 5 wt%l 30 wt% v ~ l npr l matrix-precursor n m. 4D ˆ /ˆ qp rs rp [21]l l l rs m, ˆ o perform s [22]l m p 4 (4D) rs m. kë ˆ Fig. 2l p l. rs ˆ o p k n PIC(pressure infiltration carbonization) p l, ~ p p l e p k ˆ e. }p kl 1e k 400 o C v dmeˆ e p m l 1e k ov l npe. n p p r l p rp o 1 e l ~ 470 o C dmeˆ p k ˆ ov m. p k ˆ ov l o l p np v ˆ Table 3. Properties of coal tar pitch used for the fabrication of the 4D carbon/carbon composites as a matrix impregnant Pitch type QI (wt%) B.I. (wt%) S.P (wt%) C (%) H (%) N (%) S (%) C/H Carbon Yield (%) Coal tar pitch 6.31 29.30 114.7 92.61 4.44 1.20 0.49 1.738 39.52
Densification of 4D Carbon Fiber Performs with Mesophase Pitch as Matrix-Precursor 175 Fig. 1. Temperature and pressure profile for pressure infiltration and carbonization. eˆ p. v rp ˆ p 30 bar, 50 bar 100 bar k l e p np np Œ, qn k p p v kp e ˆ pl p v m. 2.2.1. r r p e p kk o ASTM C373-88 l p t p pn l (bulk) m. ep p. Bulk Density, B = D ------------- M S D : e p 150 Cl s ml p o S : e p v l 5e p m v p t M : e p p r r 2.2.2. p ˆ p r p ˆ pp r o TA Instruments p Model 51 Thermo Gravimetric Analyser(TGA) n m. v o v 100 cc/minp tp m, m ml 800 C v o 10 C/minp o dm m. Ë 2.2.3. o AR, ˆ ˆ, HPC-25C, HPC-30Cl l p C, H, N, S p o p C/H o o p m. n p FISONS Instrument p EA-1110p n m, p p r l ˆ l 60 Cl 2e k s l r o m. Ë 2.2.4. l l 1 rp, e p o l 1000 o C v ˆ. e ˆ l p ˆ v p 2400 o C v l m. 1000 o C v l} ˆ v tl kv pnl, v p o p sq l rl p p r. ˆ p s lp e pl q l r honeycomb ˆp s p l l s r. p rl ˆ vp svp v d k, sp l p p p p. p e l v precursor n AR p l, k rl qn k p vp o ~ ˆ ˆ l l m s m. l e p r s rl n X- r (XRD) RIGAKU p D/MAX-ÕC pn m, rkp 40 kv 45 ma, r p 2θ = 20~90 o p ol 3 o /minp scan speed r m. lp q q l p 2θ Bragg's lawl p m. Ën λ = 2d sin θ Ë l λ, θ d X-ray Žq, r p. rp p rp Scherrerep pn l m. ËLc = Kλ / β cosθ Ë l K 0.9p, λ Žq(1.54056 Å), β radianp e (002) l p FWHM(full width half maximum)p. l (g) p p Maire-Meringep pn l m. g = 3.440 d --------------------------- 002 0.086 2.2.5. morphology 1 r l e p autoclavel tl v m l np ˆ ~ mp p llv. p p e s l p AR, ˆ ˆ, p l l p kp. p o Mediacybernetics p Image-Pro Plus 4.5, Image analyzer n m. 1 r l l n l Struers Minitomp n l e p, 70 o Cl k 2e k se. p t e p 30 p p p m. 2400 o C l cokes 1 p ˆ /ˆ qp sm morphologyp prp s o TOPCON p SM-500 Scanning Electron Microscope(SEM)
176 H.-J. Joo and J.-W. Lee / Carbon Science Vol. 6, No. 3 (2005) 173-180 pn l m. 3. y kyœ "3ve t x AR l} rl p p pl ˆ /ˆ qp rs rl ˆ o p p pp r. pm p po p p rl o p ~ l k ˆ rp m, ˆ dp Image analyzer Fig. 2 3l ˆ l. Fig. 2p AR l p 1 wt%, 3 wt% 5 wt% ~ l ˆ dl. p ~ v k AR d l kt qp p p l p. p 1 wt%m 3 wt% ~ e l p r q j ƒrpp p p. AR ˆ np~ r p r ˆ l np p o p r p ~ p v p p pl p p., p ~ n, p rp l v np~ p q p l qnp l p ~ p l p el p Ž l ~ n el p p e ˆ p. p r p ~ mp p l o kl l l l v. Fig. 2l m y p 5 wt% ~ n l l. Fig. 3l AR l ˆ ˆ 10 wt% ~ nl q p q l p. p n AR (Fig. 3) p v lpp k p. l l 3 wt% p ~ p ~ pl p l. p p rrp AR l ˆ ˆ 10 wt% ~ o p p e p. 30 wt%p ˆ ˆ ~ n o p n l 10 wt% ~ e ƒ l. l l 3 wt% p ~ lp l. 30 wt% ˆ ˆ AR l ~ lp p p vp ˆ ˆ yp p l p ˆ v kk. y NPSQIPMPHZ w l l s X- r l p m. Table 5 AR p v ˆ k l XRD Fig. 2. The result of image analysis of bubbling phenomenon of AR pitches.
Densification of 4D Carbon Fiber Performs with Mesophase Pitch as Matrix-Precursor 177 Fig. 3. The result of image analysis of bubbling phenomenon of pitches. p. lp ˆ l} m 2000 o C p l r, d 002. lp mr r p p p 3.354 Ål r rp Lc p } m l t v l 300 Å p ˆ. Table 5l AR ˆ k p v l v pp, AR m ˆˆ AR p l p s n p ˆ. l p ~ AR m ˆˆ kq l p p. vp ˆ rp ~ l s llv lp s vp s m v l l p m p. ˆ p s v, k, dm ˆ s p ˆl p l ˆ. Fig. 4m Fig. 5p AR l vp k p k ˆ dp e AR l p 3 wt% ~ l ˆ k 100 barl ˆ eˆ d e p e 2400 Table 5. XRD analysis of graphite derived from pitches and modified pitches Specimen Carbonization pressure(bar) d 002 (Å) Crystalline thickness Lc (Å) Graphitization degree (%) AR pitch 30 3.4010 107.599 45.35 AR pitch 50 3.3871 206.006 61.51 AR pitch 100 3.3833 208.653 65.93 AR pitch + 3 wt%c.b. 100 3.3858 160.275 63.02 Coal tar pitch 100 3.3909 190.592 57.09 Coal tar pitch+ 3 wt%c.b. 100 3.3972 143.097 49.77 AR pitch + 10 wt% coal tar pitch 100 3.3858 220.487 63.02 AR pitch + 10 wt% coal tar pitch+ 3 wt%c.b. 100 3.3934 149.396 54.19 AR pitch + 30 wt% coal tar pitch 100 3.3820 202.444 67.44 AR pitch + 30 wt% coal tar pitch+ 3 wt%c.b. 100 3.3845 199.466 64.53
178 H.-J. Joo and J.-W. Lee / Carbon Science Vol. 6, No. 3 (2005) 173-180 Fig. 5. SEM micrographs of graphite morphologies derived from AR pitch added carbon black and coal tar pitch by pressure-carbonization at 100 bar. p Table 5p m. p ~ e l l rp d 002 e l r p, rp Lc q ˆ.» QSFDVSTPS ve k d Fig. 4. SEM micrographs of graphite derived from AR pitch by pressure-carbonization. o C v l } l dp rq vp. l m p p ~ v kp e l l} r l s q lp r mll p s p pl. p 3 wt% ~ r p ˆ l e l k s ll. p ~ e p p Fig. 5l ˆ p. p l q p lamellar ˆm p Ž s p el p. p l p ~ l v l lr p. p p rp ˆ pp q p ˆ pp o v l r p s p l plk. ss vp o p l ˆ oqm oqp ˆ pp rp m. e l vprecursorp p o p l ˆ / oq Table 6l ˆ. ˆ oqp p AR ˆ ˆ l ˆ p ˆ / oqp r ˆ. p p AR p v p ˆ ˆ l rv e p p p. Fig. 6p AR m ˆ ˆ p lt p p. p 200 o C r eq, 400 Ë l q pl. 600 o C l pp p m p p p. 800
Densification of 4D Carbon Fiber Performs with Mesophase Pitch as Matrix-Precursor 179 Table 6. Elemental analysis of pitches carbon hydrogen nitrogen C/H ratio Coal tar pitch 93.333 4.4391 1.2794 1.75 AR pitch 94.2759 5.2007 0.1963 1.51 Fig. 7. Density increase measured with various C/C composites derived from 4D preform after carbonization pressure at different pressures. Fig. 6. TGA curve of AR & coal tar pitch. o C v cokep pp AR 70.83 wt% ˆˆ p 40.29 wt% r ˆ. AR pp p opp p polyaromatic q p p l cokes s p. y AR m v n l 1 rp ˆ 4D ˆ /ˆ q e p r l m. Fig. 7p rl k p rs ˆ /ˆ qp v p ˆ p. q l ˆ k p p ˆ pp kr sp pp p p. p 3 wt% ~ AR m AR l 10% ˆˆ p q p lt p. ˆˆ l 3 wt% p ~ nl l l p p. Fig. 8p p ~ l v ˆ p. ˆ rl k p 100 bar rn m. AR p 1 wt% ~ 3 wt% ~ n n ˆ. v 5 wt%, 10 wt%p p ~ l e kp p kp k mp p q v kk l r v kk. Fig. 8. Density increase of C/C composites derived from 4D preform according to amount of added carbon black. (pressure: 100 bar) k ˆ v p l l np v kp (powder) ˆm p np ˆ l. ˆˆ p n p ~ l p rrp ˆ. ˆˆ AR AR l 10 wt%p ˆˆ ~ mp p v p k ˆ. Fig. 9 100 kp k rp m profilel v precursorl 3 wt%p p ~ v precursor l p p lt p. p p s p AR l ˆˆ 10 wt% ~ mp
180 H.-J. Joo and J.-W. Lee / Carbon Science Vol. 6, No. 3 (2005) 173-180 l r. l ˆˆ l AR n p, ~ l p l r ˆˆ n pp m. 1 p rl AR l ˆˆ 10 wt% ~ 3 wt%p p ~ m p q sp pp ˆ l. r p n p vp rp eˆ pp p. y Fig. 9. Density of C/C composites derived from 4D preform with various matrix-precursors (added 3 wt% carbon black, pressure: 100 bar) p v q p k p. 4. l l weaving typep 4 ˆ o p rs, k ˆ rp ˆ /ˆ q r s m. 4D ˆ o p rl r rkp ˆ p rp o l v mesophase v precursor n m., ˆ rl AR n p l ˆ v p l n rp o l p ~ l e p p p ll. AR p ˆ rl p p ~ rl plp, ˆ /ˆ qp prp v o ~ p 3 wt% r rpl. p ~ m l} rl l l l p ~ v kp [1] Fitzer, E. Carbon 1987, 25(2), 163. [2] Lamicq, P. J. International Carbon Conference, Bordeaux, France, 1984. [3] Sheehan, J. L. Carbon 1989, 27, 709. [4] Jones, L. E.; Thrower, P. A. Carbon 1991, 29, 251. [5] By Courtesy SEP (Societe Eupropeene de Propulsion), Puteaux, France, 1982. [6] Curry, D. M.; Scott, H. C.; Webster, C. N. 25 th National SAMPLE Symposium 1979, 1524. [7] Burchell, T. D. The European Carbon Conference Carbon 96, Newcastle, UK 1996, July 187. [8] Fitzer, E. Carbon fibers and their composites (A Review), High temp.-high pressure 1984, 16, 363-392. [9] Fitzer, E.; Gkogkidis, A. Carbon fiber reinforced carbon composites fabricated by liquid impregnation, Petroleumderived carber, ACS Symposium series 303 1986, 346-378. [10] Batha, H. D. et al. Engineered materials handbook composites, ASM International 1987, 922-923. [11] Baojian, P. et al. Tribological characteristics of carbon/ carbon composites, 19th Biennial Conference on Carbon 1989, 352-353. [12] Fitzer, E.; Yamada, S.; Schaffer, W. Carbon 1969, 7, 643. [13] Fitzer, E.; Terwiesch, B. Carbon 1973, 11, 570-574. [14] Joo, H. J.; Lee, Y. J. Carbon 2002, 3(2), 85. [15] Joo, H. J.; Lee, Y. J. Composites part A35, 2004, 1285.