액정고분자 복합계의 in-situ 횡당면 배향을 위한 공정개발

김영석; 이재욱

Korean Journal of Rheology, Vol.10, No.2, 82-91, June, 1998

Export Citation

액정고분자 복합계의 in-situ 횡당면 배향을 위한 공정개발

Process Development for in-situ Transverse Orientation of TLCP Fibril in PC/TLCP Blends

김영석, 이재욱

초록

액정고분자/폴리카보네이트 혼합계로 구성된 분자복합재를 쉬트상으로 가공할 때 취약해지기 쉬운 횡단면 방향의 물성을 향상시키기 위하여 미세섬유상의 배향을 in-situ 상태로 적 절히 제어할 수 있는 Simultaneous Convergent-Divergent(SCD) 다이를 설계·제작하고 압출실험을 수행하여 얻은 압출 쉬트를 대상으로 구조-물성-가공의 상관관계를 조사하였다 액정고분자의 첨가 함량에 따른 토오크와 토출량의 변화는 액정고분자를 10 wt% 소량 첨가하였음에도 현저한 감소 효과를 보였으며, 약 30wt%일 때 최소로 되었다 이는 액정고분자가 보강 기능외에 가공특성의 개선에도 큰 효과가 있어 가공조제로서의 가능성을 보이는 결과로 혼합계의 유변학적 특성 결과에서도 확인할 수 있었다 또 DSC와 DMA를 이용한 열분석 결과 액정고분자의 함량이 증가함에 따라 PC의 유리전이온도가 다소 감소하는 현상을 보임에 미루어 이 혼합계는 부분적으로 상용성을 갖는 것으로 볼 수 있으며, 모폴로I지 분석을 통해서도 이를 확인할 수 있었다. TLCP/PC 혼합계로 구성되는 분자복합재를 SCD 다이를 사용하여 제조한 압출 쉬트의 방향성에 따른 기계적 물성은 기존의 쉬트 다이보다 흐름 방향으로는 다소 낮은 물성치를 보이지만 횡단면 방향으로는 물성이 현저허 향상됨을 관찰할 수 있었다 모폴로지 분석 결과 기존의 쉬트 다이의 경우 벽면 부근에서는 액정고분자가 미세섬유상으로 형성되어 흐름 방향으로 배향되어 있지만 중심부에서는 액적 상태로 존재하는 반면, SCD다이의 경우 미세섬유상으로 형성된 액정고분자가 벽면에서부터 중심부로 갈수록 횡단면 방향으로 서서히 배향되어 있음을 확인할 수 있었다.

To enhance the transverse properties of molecular composite composed of TLCP/PC blend systems, we designed simultaneous convergent-divergent(SCD) die for proper control of the fibril orientation in in-situ state and examined the interrelationships of structure-property-processing characteristics after formation of sheet by extrusion process. The changes of torque and output flow rate showed the remarkable reduction in addition of only small amounts of TLCP and had a minimum reduction at 30 wt% of TLCP. Thus TLCP has a potential as a processing aid because TLCP showed the large effects on the improvement of processing characteristics as well as reinforcing factors, which was confirmed from the rheological characteristics of blend systems. In the thermal behavior obtained by DSC and DMA, we found that TLCP is partially com-patible with PC from the results that the Tg of PC component slightly decreases with increasing the content of TLCP. This was ascertained by morphological interpretation. A sheet was obtained by extruding the TLCP/PC blends with a SCD die. The mechanical properties of flow and transverse directions for extruded sheet obtained by SCD die put down the intermediate those by traditional sheet die. That is, the mechanical properties in the transverse direction of sheet obtained by SCD die obviously enhanced while the properties in the flow direction appeared some lower than those of traditional sheet die. SEM micrographs revealed that TLCP droplets in the specimen by traditional sheet die were fibrilated and elongated only in the flow direction near the wall. but they still remained at the center. On the contrary, morphology of the sheet obtained by SCD die shows that TLCP fibrils oriented progressively in the transverse direction from wall to center.

Keywords:Liquid crystalline polymer;molecular composite;rheological properties;simultaneous convergent-divergent die;in-situ transverse orientation

[References]

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Hsiung CM, Cakmak M, Int. Polym. Process., 3, 255 (1993)
Valenza A, La Mantia FP, Paci M, Magagnini PL, Int. Polym. Process., 3, 247 (1991)
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La Mantia FP, Valenza A, Makromol. Chem. Macromol. Symp., 38, 183 (1990)
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Sukhadia AM, Done D, Baird DG, Polym. Eng. Sci., 30, 519 (1990)
Min K, White JL, Fellers JF, Polym. Eng. Sci., 24, 1327 (1984)
La Mantia FP, Valenza A, Magagnini PL, Paci M, Rheol. Acta, 28, 417 (1989)

[1] Kiss G, Polym. Eng. Sci., 27, 410 (1987)

[2] Weiss RA, huh W, Nicolais L, High Modulus Polymers, p. 145, A.Z. Zachariades and R.S. Porter, eds., Marcel Dekker, New York (1988)

[3] Browtow W, Polymer, 31, 979 (1990)

[4] Crevecoeur G, Groeninckx G, Bull. Soc. Chim. Belg., 99, 1031 (1990)

[5] Kulichikhin VG, Plate NA, Polym. Sci. U.S.S.R., 33, 1 (1991)

[6] Chin HB, Han CD, J. Rheol., 23, 557 (1979)

[7] Tsebrenko M, Rezanera N, Vinnogradov G, Polym. Eng. Sci., 20, 1023 (1980)

[8] Amundsen RJ, Master's Thesis, The University of Michigan, Mich. (1990)

[9] Kohli A, Chung N, Weiss RA, Polym. Eng. Sci., 29, 573 (1989)

[10] Isayev AI, Modic MJ, Polym. Compos., 8, 158 (1987)

[11] Deery D, Kenig S, Siegmann A, Polym. Eng. Sci., 31, 451 (1991)

[12] Goettler LA, Leib RI, Lambright AJ, Rubber Chem. Technol., 52, 838 (1979)

[13] Bassett BR, Yee AF, Polym. Compos., 11, 10 (1990)

[14] Dutta D, Weiss RA, Polym. Eng. Sci., 13, 394 (1992)

[15] Hsiung CM, Cakmak M, Int. Polym. Process., 3, 255 (1993)

[16] Valenza A, La Mantia FP, Paci M, Magagnini PL, Int. Polym. Process., 3, 247 (1991)

[17] Incarnato L, Nobile MR, Frigione M, Motta O, Acierno D, Int. Polym. Process., 3, 191 (1993)

[18] Hoechst-Celanese Co., Vectra B950 Safety Data Sheet (1991)

[19] La Mantia FP, Valenza A, Polym. Eng. Sci., 29, 625 (1989)

[20] Nobile MR, Amendola MR, Nicolais E, Acierno L, Carfagna C, Polym. Eng. Sci., 29, 244 (1989)

[21] Gotsis AD, Baird DG, J. Rheol., 35, 1191 (1986)

[22] Volkov VS, Kulichikhin VG, J. Rheol., 34, 281 (1990)

[23] Crevecoeur G, Groeninckx G, Polym. Eng. Sci., 30, 532 (1990)

[24] La Mantia FP, Valenza A, Makromol. Chem. Macromol. Symp., 38, 183 (1990)

[25] Onogi S, Asada T, Rheology, Vol. 1, ed. G. Astarita, G. Marrucci and L. Nicholais, Plenum, New York (1980)

[26] Gotsis AD, Baird DG, J. Rheol., 35, 1191 (1986)

[27] De'Neve T, Navard P, Kleman M, J. Rheol., 37, 515 (1993)

[28] Sukhadia AM, Done D, Baird DG, Polym. Eng. Sci., 30, 519 (1990)

[29] Min K, White JL, Fellers JF, Polym. Eng. Sci., 24, 1327 (1984)

[30] La Mantia FP, Valenza A, Magagnini PL, Paci M, Rheol. Acta, 28, 417 (1989)