Korean Chemical Engineering Research

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(1)Korean Chem. Eng. Res., Vol. 43, No. 1, February, 2005, pp. 16-20. CO2 5Ï kÿg ?à ¿ô§ /@| ?÷O§W £ g». ¿

(2) K <÷K. †. èî¬HG dHàHê , ¤òQ ß8g wM 300 ö ³ 28³ [¤, 2004¸ 11ö 1³ >). 440-746 (2004 6. Preparation of Porous Polypropylene Membrane by a Thermally Induced Phase Separation Method in Supercritical CO2 Sang-Joon Lee and Jaygwan G. Chung† Department of Chemical Engineering, Sungkyunkwan University, 300, Chunchun-dong, Jangan-gu, Suwon 440-746, Korea (Received 28 June 2004; accepted 1 November 2004). ß È. CO ð»ª KÑ ùRHs «ÄGñ ·-é³1Wê #Ss HYGñ à ·-é³1W Ls fÆ|. · -é³1W 10 wt% ÆQÑ fÆê ·-é³1W L àÕo è!9, Ñ!9, n-z!9Ñ ¶ ÎÎ 78, 80, 73%. ·-é³1W Í ÍO¤´ ¯ßã2 4k ·-é³1W Í 10 wt% ³ ) ¯ßã 2 0.17 kg /mm . CO ð»ª Kõ ÄGñ #Ss K ê QÑÑ ¶ Í ÍGk 5~ ê á 94% fMæÉ. 5Í ÍWÑ ¶ Í Í|k 45 C ÆQÑ 99% fMæÉ. 6÷ « o 5Ñ2 2 IGæÉ. 150 bar Ft>(2 Ft« ÍWÑ ¶ #S 2 ÍGk÷, « Ft ÆQÑ2 Ft« ÍWÑ ¶ 2 ÂGj Ý|. 2 CO ð» ª K #SÑ ¬K Äg 7 ê î « ÀÉ. 2. 2. f. 2. o. 2. Abstract − Porous polypropylene membranes were prepared by a thermally induced phase separation method in supercritical CO2, where polypropylene and Camphene were used as raw materials. The porosity of polypropylene membranes with 10 wt% polypropylene concentration was 78, 80, 73% by using methanol, ethanol, and n-buthanol as an analytical solvent, respectively. The tensile strength increased with an increasing polypropylene concentration, where it was 0.17 kgf/mm2 at 10 wt% polypropylene concentration. The extraction rate for Camphene increased with time and Camphene was removed 94% in 5 min. It increased with an increasing temperature and was 99% at 45 oC, however, decreased with an increasing temperature at higher than 45 oC. The extraction rate increased with an increasing pressue up to 150 bar, however, decreased slightly with an increasing pressure over 150 bar. The extraction rate had a relation with the solubility of Camphene in supercritical CO2. Key words: Porous Polypropylene Membrane, Camphene, Supercritical CO2, Thermal Induced Phase Separation Method. 1.. C «. (>( õgê à Ê~É L é2 ·-¬³(polysulfone), ·-Ñºí¬³(polyethersulfone), ·-«ÂÃ(polyimide), ·- «ÂÎ(polybenzimida- zole), ·-2 4Î(polyoxadiazole), · -¯)²j(polyphosphazene) Ù« À[2]. U¾ ·-é³1W (polypropylene)o £ , ù , KH , ¤ Ú u\ « ´û Ê~É³ õgÉÀk[3] Bae Ù[4]o ·-é³1W s «ÄGñ à Ê~É Mg0Ls fÆGÊ fÆÆQÑ !ñ ¡dõ õgGk, Yangê Perng [5]o ùRrs «ÄGñ ·-é³1W à ~-Ls ÁSJk³ fÊO ¤ À2 ê õ è,|. Matsuyama Ù[6]o ùRr fÆ ÆQÑ !¶ ·é³1W à ~-L gÆõ ÆQO ¤ ÀÉ2 õgêõ è,|. Evren [7]o ·-é³1W à ~-Ls «ÄGñ. í0é« èWÑ !¶ Æd, ,ªd, Éd Ùk³ ¯Ño b®³Ò @ls 5 ¤ Àj æÉ(O Ñ !¶ h 1ê Ñ w( éfÍ [ÎGj ¬&æÉ. ÖÑ2 «6K éfõ gG , .g K õgÍ ,}æÊ Àk O à Ê~É L fÆQ ÄÑ ¬K õg2 «: îYÑ ÆJ, ¡J î[s çÊ À. à Ê~ÉLo í ê fÊ « Î¤Gñ ,~-, _Êñê, ò·, e·ê ço ~-à_ Lk³ O 4n¶ õ0M( é³ Gj JÄæÊ À[1]. † To. whom correspondence should be addressed. E-mail: [email protected]. 16.

(3) CO2. ð»ª KÑ ùRHõ «ÄK à ·-é³1W L fÆ. M èn s ¤HJk³ |. Mdro Ê~ÉL fÆWÄ« Jj ËÊ ¬ fÆßjÍ 1 ® Ç, AéÑ W¬ Ls fÆG, .K örk³ - Äæ Ê À. Mdro è³K ³ Ê~É ÄUk³z Äk fM, WÄk Í Ùs 0Gñ ~-õ KGñ ÊdQk ³ Ls fÆG2 ör« Q5Rr, 5Rr, ùRr Ú Ê~É õ «ÄG2 ör Ù« À. à Ê~É Lo Q5Rr 2 5 Rrk³ fÆæÊ ÀÉk MÑ2 ùRrs «ÄK Ê~É L fÆÑ îK õgÍ ,}æÊ À[8, 9]. 6÷ ,Ê Mdro ¯Ñ KgK ÄkËs ÄG, A éÑ h s 1Q ÎsÍ Àk £~K Mdõ ,}G, . g 0 äQÑ« 1®G2 Ys (nÊ ÀÉ. «6K éf Ys gGÊ Ê~É L í s íG, .g MdrÑ e Í uíÊ ÄgÍ o ð»ª Kõ JÄ|[10, 11]. Matsuyama Ù[12, 13]ê Lee Ù[14]o ð»ª Kõ «ÄGñ à 0 ~-Ls fÊG2) ð»ª CO Ft« 80-160 barÑ2 F t« ÍO¤´ L àÕ« Í|k 20-70 C p.Ñ2 5 Í s¤´ àÕ« ÍKÊ è,|. «A Matsuyama Ùê Lee Ùo ÎÎ ¯X³1 4§º«T Lê Y- Ls Ä|. 6÷ (>( ð»ª Kõ Äk³ ÄK õgËo ¯ X³1 4§º«T Lê Y- L Ù ³z Ê~É éÑ K_ æÉk pÄJk³ ÄæÊ À2 W¬ à Lo 4)>( ,Ê Kg Äkõ «ÄGñ fÆGÊ ÀÉ. á Y×Ñ2 CO ð»ª Kõ «ÄGñ ,ªJ U « Î¤GÊ ¤(Í« I K à ·-é³1W Ls fÆGk 5S(camphene)s ÍGñ à L U s f´|. ÆQÑ !ñ àÕê ¯ß ãõ WG|k CO ð»ª K äQÑ, 5, FtÑ ! ñ ¸S õ +_GÊ MJ ÆQs _|.. 17. O2. Fig. 1. Preparation of porous polypropylene membrane by a thermally induced phase separation method.. 2. o. 2. 2. 2.. / . 2-1. ' L é³ ÄK ·-é³1W(HP524J, Polymirae., Korea, Melting index: 3 g/10 min)o 24QÑ 8 100 C ÆQÑ £~ ¾ QÆK áÑ ÄGk, àÕs f´G2) ÄG2 5S (Camphene, 3,3-Dimethyl-2-methylenenor-camphene, Merck Co., U.S.A., ¨ 95% « )o ¥ Ms-ê_ Ç« ÄG. 2-2. /tà ·-é³1W à Lo Fig. 1ê ço ê_s M° fÆ|[15]. ·-é³1Ws 5Sê HYK á 150 C³ ÍùGñ ³ Ä Uk³ fÆ|. fÆê HYÄUs Â- 150 C³ ùæ´ À & í K-¶ «Ñ ³_

(4) Ê K-¶k³ FôG ñ Ls OËÉ. ·-é³1W ÄU« L =³ æ

(5) · -é³1W« ½ê K-¶s 15 C Í¤Ñ Ê 5~ 8 -QZ[15]. ê ·-é³1W ÊLs Fig. 2Q ço ä ,Ñ Ê_K á (V1)õ ù´ CO Í)õ -ÎQE ä,Ñ o á(V2s «ÄGñ K

(6) ÆQ) Lk³z 5Ss |. ä,(Ilshin Autoclave Co., Korea) Ä

(7) o 300 cm « ä QÑ, 5, FtÑ !ñ õ ÁSJk³ ÍG, .g W Y×s 0g »o êõ ¬³ äQÑ 5-40~, ä Ft 110o. o. o. o. Fig. 2. Schematic diagram of an experimental apparatus.. ä 5 35 C-65 C ÆQÑ Y×s |. ä « ³û á (V3)õ ù

(8) U = «d!2 ,Í æ´ ¬, k³ fMæÊ à ·-é³1W Ls »É[16]. ·-é³1W L àÕo è!9, Ñ!9, z!9 ÄUs Ä k³ ÄGñ +_|k R (1) [17]³ àÕ(p, %)s ª |. o. 190 bar,. o. ma -----ρa - × 100 p = -----------------ma mp ------ + -----ρa ρp. (1). 2 5O LÑ ¤ê ÄU 0

(9) (g), m 2 QÆê L 0

(10) (g) « ρ (g/cm )Q ρ (g/cm )2 ÎÎ Äk ÊQ Ê~É ¤( Êõ ÷. Ê~É Ls 1QÑ 8 ÄkÑ Í&ÉÍ 5 õ 5(25 C)>( -Ê ,

(11) Äkõ fMK á 10ð « Ñ MÉIÖ(AB204-S, Mettler Toredo, Co., Switzerland)õ «ÄG ñ èO 0

(12) s +_Gk, QÆ 1Ñ 80 C, 6QÑ 8 Q ÆQ á QÆ0

(13) s +_|. SEM(XL30 ESEM-FEG, FEI Co., U.S.A.)s «ÄGñ L

(14) s îû|k ·-é³1W L ¯ßã(tensile strength)2 ¯ß+_,(Instron UTM III, Toyo Baldwin, Japan)õ ÄGñ + _|. L zÑ ÍÍGÊ À2 5S 2 NMR(Varian 500 NB, Varian Co., U.S.A.)s «ÄGñ +_|. ma. p. 3. a. 3. b. o. o. 2. 3. 3.. ûG Z +{. 3-1. ?÷O§W ØK | C£ß Lð ·-é³1W Í L àÕÑ Âj2 s <4Ý, . Korean Chem. Eng. Res., Vol. 43, No. 1, February, 2005.

(15) « Cö_éî. 18. g ·-é³1W õ ÎÎ 10, 20, 30 wt% ÆQk³ ÎÎ fÆGÊ L

(16) s Fig. 3ê ç« WG|. ·-é³1W à Lo ·-é³1W Ñ !¶ îûê à ¡dÍ kÎ Â§Gk÷, ·-é³1W Í ÍO¤´ à ¿,Í Ê4(2 as îûO ¤ ÀÉ. à ~¯2 5S. Q -Î 5Ñ !¶ ¡G2 ak³ îûæÉ. -Î 5Í s¤´ à ¿,2 ÊÊ à ~¯¤2 Í|2) Fig. 3ê ç« 5 Í 35 C³ ³_K Î 5S Í ÍO¤´ à ¿,2 Í |. 6÷ à ~¯¤ Ý ñz2 ¶O ¤ ÇÉ. àÕo Äæ2 ÄkÑ !¶ à LÑ ¬K z· « ¶ (, AéÑ è!9(methanol), Ñ!9(ethanol), z!9(n-butanol) § Í( Äkõ «ÄGñ ÎÎ +_|k[17] ê2 Table 1Ñ ÷,. Ñ!9s ÄG2 Î àÕ« MJk³ Íß I2) « ao ·-é³1WÑ ¬K Ñ!9 z· « Íß o ê«, 10 wt% ÆQÑ 80% àÕs ä2 ak³ ÷

(17) . è! 9ê n-z!9s ÄG2 Î àÕo ÎÎ 78%Q 73%. 20 wt% ·-é³1Ws ÄG2 Î àÕo è!9, Ñ!9, n-z!9Ñ ÎÎ 76, 76, 69%k 30 wt% ·-é³1Ws. ÄG2 ÎÑ2 àÕo è!9, Ñ!9, n-z!9Ñ ÎÎ 74, 71, 64%. ·-é³1WLo ¤ Lk³ ÄkÑ ¬K `{ « í, ¤ Äk³¤´ z· o ÍK. è!9, Ñ!9, n-z !9 ¨k³ ¤ o ÍG, AéÑ z· Ígt G(O Äk ÊÍ (, AéÑ Table 1ê ç« ·-é³1W Í 30 wt%¯ L Î è!9, Ñ!9, n-z!9 ¨k³ z· o ©´Ê ê àÕ 4. «Q ç« ·-é³1W L o Äk³ Äê 5S« ê z~« àk³ æ, AéÑ ·-é³1W Í s¤´ àÕo 4. ·-é³1W Ñ !ñ L ¯ßãõ Fig. 4Q ç« + _|. ·-é³1W à Lo ·-é³1W Í ÍO¤´ ¯ ßãÍ ÍG2 s Ý. 10 wt% ·-é³1Ws Ä K L ÎÑ2 0.17 kg /mm ²'Ys ä2 ak³ îûæÉ k 20 wt%Q 30 wt% ·-é³1Ws ÄK L ²'Yo ÎÎ 0.24, 0.46 kg /mm . «Q ç« ·-é³1W Í ÍWÑ !¶ L ¯ßã(²'Y)Í ÍG2 ao ·-é³1W Í L _d ÍÑ s Âr O 4n¶ L z àÕs IGQ ê³ _ê.. Table 1. Porosities of polypropylene membranes with an increasing polypropylene concentration by using methanol, ethanol, (Unit: %) and n-butanol PP concentration Solvent Methanol Ethanol n-Butanol. 10 wt%. 20 wt%. 30 wt%. 78 80 73. 76 76 69. 74 71 64. o. 2. f. 2. f. Fig. 4. Relationship between tensile strength of membrane and strain with an increasing polypropylene concentration of (a) 10 wt%, (b) 20 wt%, and (c) 30 wt% in 10 min at 35 oC and 150 bar.. 3-2. C0 SÏ kÿg c'O, s, p¿ [ç ßç C£ß Lð CO ð»ª KÑ Ê~É L zÑ ÍÊg À2 5Ss Á SJk³ O ¤ À2 MJÆQs _G, .Gñ äQÑ, 5 , Ft ÆQ¥ õ {ê ç« +_|. ð»ª K2 ,

(18) ßt« 4 L z³ z·Í uíÊ, e ª¤Í í0 ÄgÍ kÎ uí[14]. U¾ CO ð» ª K2 Í« IGÊ h ndJ«, AéÑ à_Ñ Q « ÄæÊ À[16]. ð»ª KÑ äQÑÑ !ñ 5S õ <4Ý, .g ·-é³1W õ 10 wt%³ Ê_GÊ 45 C, 150 bar ÆQ Ñ 5, 10, 20, 30, 40~ ê á gK 5S õ Fig. 5Ñ ÷,. ð, LÑ2 90 wt% 5S« ÊéGÊ ÀÉk 5~ ê á ð, 94%Í æÉk 10~ ê áÑ2 ð, 2. 2. 2. o. Fig. 3. Cross section images of the membranes prepared with polypropylene concentration of (a) 10 wt%, (b) 20 wt%, and (c) 30 wt% in 10 min at 35 oC and 150 bar.. ¤@¤ C43× C1 2005 2.

(19) CO2. ð»ª KÑ ùRHõ «ÄK à ·-é³1W L fÆ. Fig. 5. Relationship between extraction rate of Camphene and time in supercritical CO2 at 45 oC and 150 bar in the presence of 10 wt% polypropylene concentration.. 99%Í æÉ. 10~ «áÑ2 IK 5S ¡ dõ îûO ¤ ÇÉk QÑÑ !¶ 2 ³_|. 10~ Ñ à_s 0Gñ O ¤ À2 M¬ 5S 2 89.1 wt% (90 wt% 0.99)« ÷Ë(2 ·-é³1W ¤( _ gÆ Ñ Í ÊGÊ À, AéÑ 5Ss 100% G, .g2 ÄGÊ À2 é à_ ÆQs ¡dQÿM÷ 3QÑ« s gt | . CO ð»ª K ¬U ¬,F ÆQÑ Ñ!9s «ÄGñ 5S õ +_g Ý

(20) 10~ ê á 82%õ ÷,k «ao ð »ª Kõ Äk³ ÄK ÎÝ u 17% _ o ê«. ³äJk³ U Äk2 5Í ÍWÑ !¶ ÄgÍ ÍG( O, ð»ª K2 FtÑ !¶ 5Q Äg Ñ îîª2 Æ QÑ !¶ ¡K[18]. Fig. 6o CO ð»ª KÑ 5Ñ !ñ 5S ÁSs ÷ ak³ 35 C, 45 C, 55 C, 65 C 5 ÆQÑ õ ÷,. ð»ª K ÁSo 35 CÑ 96%, 45 CÑ 99%³ Í YY 9GÍ 55 C, 65 CÑ2 ÎÎ 88%, 85%³ Í YY 4. 150 bar FtÆQÑ 5S 2 45 C >(2 5Ñ !¶ ÍGÍ « 5p.Ñ 2 5Í ÍWÑ !¶ 1¾s Í ÝG2 s Ý . «ao 150 bar CO ð»ª KÑ 45 C >(2 5SÑ ¬K ÄgÍ 9|(O 45 C « 5Ñ2 CO ð»ª K ÊÍ 4(

(21) 1¾s ÄgÍ ©´, ê³ @ÎæÉ . CO ð»ª K ¬U ¬,F ÆQÑ Ñ!9s «ÄGñ 5 S õ +_g Ý

(22) 45 C 5 ÆQÑ 10~ ê á 84%õ ÷,k «ao ð»ª Kõ Äk³ ÄK ÎÝ u 15% _ o ê«. CO ð»ª K2 Ft« ÍWÑ !¶ ÊÍ ÍG

(23) Ä gÍ ÍK[19]. Fig. 7Ñ2 ð»ª K FtÑ !ñ 5 S õ ÷Ék, 10~, 45 C äÆQÑ 110, 130, 150, 170, 190 bar FtÆQÑ !ñ õ WG|. ð»ª K Ft« 110, 130, 150 bar³ AÑ2 5S . 19. Fig. 6. Relationship between extraction rate of Camphene in supercritical CO2 and temperature in 10 min at 150 bar in the presence of 10 wt% polypropylene concentration.. 2. 2. o. o. o. o. o. o. o. o. o. o. 2. o. 2. 2. o. 2. o. Fig. 7. Relationship between extraction rate of Camphene in supercritical CO2 and pressure in 10 min at 45 oC in the presence of 10 wt% polypropylene concentration.. Í ÎÎ 93, 94, 99%³ FtÑ !¶ Í|. 6÷ 170, 190 bar Ñ2 ÎÎ 88, 85%³ Ft« ÍWÑ !¶ Í Ý| . «ao CO ð»ª K Äg2 FtÑ !¶ ÍG Fig. 7 Ñ Ý«2 àQ ç« 150 barÑ Í Íß Ik « FtÆQÑ ÄgÍ Íß o ak³ æÉ. ð»ª K Äg(X), Ft(P), 5(T) Ñ îª2 R (2)³ ÷,[18]. 2. 1 0.369 –1 –2 * log X= X = ----  2.79 × 10 T – 9.32 + ------------- + log P – log P  V V . (2). R (2)õ QdQÿ

(24) 45 C 5ÆQÑ 80, 100, 130 bar FtÆQÑ 5S Äg2 1.45, 1.52, 1.64 mol%³ ¾ o. Korean Chem. Eng. Res., Vol. 43, No. 1, February, 2005.

(25) « Cö_éî. 20. ÍGÍ 150 barÑ 1.69 mol%³ Íß ÄgÍ o ak³ ÷

(26) . -Ê 160, 200, 300 barÑ2 1.65, 1.58, 1.51 mol%³ ¾ Ý|. Fig. 7ê WGg å A, Í Íß I Ft 150 barÑ Äg Íß I. 5S 2 CO ð»ª K 5S ÄgQ î « À2 ak³ Ý¯. 2. 4.. û «. á õgÑ2 CO ð»ª Kõ «ÄGñ ·-é³1W à Ls fÆGk ð»ª K äQÑ, 5, Ft« à L àÕê ¯ßãÑ Âj2 Ñ îGñ Y×|. « A 5Ss ÄGñ L àÕs ÆQGk Y×s 0g »o ê2 {ê çI. (1) Ñ!9s ÄG2 Î àÕ« MJk³ Íß Ik 10, 20, 30 wt% ·-é³1W ÆQÑ àÕo ÎÎ 80, 76, 71%. (2) 10 wt% ·-é³1Ws ÄK L ÎÑ 0.17 kg /mm ²'Ys ä2 ak³ îûæÉk 20ê 30 wt% ·-é³1 Ws ÄK L ²'Yo ÎÎ 0.24, 0.46 kg /mm . (3) ð, LÑ2 90 wt% 5S« ÊéGÊ ÀÉk 5~ ê á ð, 94%Í æÉk 10~ ê áÑ2 ð,. 99%Í æÉ. 10~ áÑ2 ¡dÍ ÇÉ. (4) ð»ª K ÁSo 35 CÑ 96%, 45 CÑ 99%³ Í YY 9GÍ 55, 65 CÑ2 ÎÎ 88, 85%³ Í YY 4. (5) ð»ª K Ft« 110, 130, 150 bar³ AÑ2 5S Í ÎÎ 93, 94, 99%³ FtÑ !¶ Í|. 6÷ 170, 190 barÑ2 ÎÎ 88, 85%³ Ft« ÍWÑ !¶ Í Ý|. 2. 2. f. 2. f. o. o. o. ÷ô{S ma. : mass of the solution absorbed in the wet membrane [g]. mp p. : mass of the dry membrane [g] : porosity of the membrane [%]. P P*. : pressure [bar] : saturation pressure [bar]. T V. : temperature [oC] : volume [cm3]. X. : solubility [mol%]. +÷¿ï SÛ. ρa. : density of solutions [g/cm3]. ρp. : density of the polypropylene [g/cm3]. +S 1. Kang, M. H., Chai, H. N. and Yang, W. K., “Relationship on Ionic Conductivity and Ionic Permeability through Polymer Membrane,” Appl. Chem., 6(1), 328-331(2002).. ¤@¤ C43× C1 2005 2. 2. Park, H. B. and Lee, Y. M., “Polymer Electrolyte Membranes for Fuel Cell,” J. Korean Ind. Eng. Chem., 13(1), 1-11(2002). 3. Lee, S. G., Lee, J. H., Choi, K. Y. and Rhee, J. M., “Phase Inversion Behavior of Polypropylene/Polystyrene Blends,” Polymer(Korea), 22(2), 258-268(1998). 4. Bae, B., Chun, B. H., Ha, H. Y., Oh, I. H. and Kim, D., “Preparation and Characterization of Plasma Treated PP Composite Electrolyte Membranes,” J. Membr. Sci., 202(1-2), 245-252(2002). 5. Yang, M. C. and Perng, J. S., “Microporous Polypropylene Tubular Membranes via Thermally Induced Phase Separation using a Novel Solvent-Camphene,” J. Membr. Sci., 187(1-2), 13-22(2001). 6. Matsuyama, H., Yuasa, M., Kitamura, Y., Teramoto, M. and Lloyd, D. R., “Structure Control of Anisotropic and Asymmetric Polypropylene Membrane Prepared by Thermally Induced Phase Separation,” J. Membr. Sci., 179(1-2), 91-100(2000). 7. Evren, V., “A Numerical Approach to the Determination of Mass Transfer Performances through Partially Wetted Microporous Membranes: Transfer of Oxygen to Water,” J. Membr. Sci., 175(1), 97-110(2000). 8. Kim, H. J., Kang. Y. S. and Kim, J. J., “Polymeric Microporous Membranes,” Polym. Sci. Technol., 2(2), 81-87(1991). 9. Atkinson, P. M. and Lloyd, D. R., “Anisotropic Flat Sheet Membrane Formation via TIPS: Atmospheric Convection and Polymer Molecular Weight Effects,” J. Membr. Sci., 175(2), 225-238(2000). 10. Kim, J. R. and Kyong, J. B., “Solubilities of Solids in Supercritical Fluids,” J. Korean. Chem. Soc., 34(4), 325-330(1990). 11. Lee, J. S., Jeon, B. J., Jung. I. H. and Hong, I. K., “Determination of Diffusion Coefficients of Extracts in Supercritical Carbon Dioxide,” J. Korean Ind. Eng. Chem., 6(2), 320-330(1995). 12. Matsuyama, H., Yano, H., Maki, T., Teramoto, M., Mishima, K. and Matsuyama, K., “Formation of Porous Flat Membrane by Phase Separation with Supercritical CO2”, J. Membr. Sci., 194(2), 157-163(2001). 13. Matsuyama, H., Yamamoto, A., Yano, H., Maki, T., Teramoto, M., Mishima, K. and Matsuyama, K., “Effect of Organic Solvents on Membrane Formation by Phase Separation with Supercritical CO2”, J. Membr. Sci., 204(1-2), 81-87(2002). 14. Lee, S. B., Kim, H. J., Jung, I. H. and Hong, I. K., “Preparation of High Performance Membrane using Supercritical Carbon Dioxide and Gas Permeability of the Membrane,” Theories and Applications of Chem. Eng., 1(1), 912-915(1995). 15. Matsuyama, H., Maki, T., Teramoto, M. and Asano, K., “Effect of Polypropylene Molecular Weight on Porous Membrane Formation by Thermally Induced Phase Separation,” J. Membr. Sci., 204(1-2), 323-328(2002). 16. Lee, S. J., Kim, M. S. and Chung, J. G., “Characteristics of Microporous Polycarbonate Membrane Prepared by a Phase Inversion Method with Supercritical CO2”, J. Korean Ind. Eng. Chem., 14(8), 1058-1063(2003). 17. Shi, Q., Yu, M., Zhou, X., Yan, Y. and Wan, C., “Structure and Performance of Porous Polymer Electrolytes Based on P(VDF-HFP) for Lithium Ion Batteries,” J. Power Sources, 103(2), 286-292(2002). 18. Kim, J. R., Kim, H. K. and Kyong, J. B., “Solubilities of Naphthalene in Supercritical Fluids,” J. Korean. Chem. Soc., 32(4), 311-317(1988). 19. Sun, Y. P., Supercritical Fluid Technology in Materials Science and Engineering, Marcel Dekker, Inc., New York, NY(2002)..

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