Factors that Affect Fibrillation of the Liquid Crystalline Polymer (LCP)Phase in an Injection Moulded Polycarbonate / LCP Blend

Abstract:

The effects of compatibilization and mould geometry on the fibrillation of liquid crystalline polymer were investigated in this study. The blend is composed of polycarbonate (PC) and LC5000, a thermotropic liquid crystalline polymer consisting of 80/20 wt% of hydroxybenzoic acid and poly(terephthalate). The effect of compatibilization was investigated by studying the morphological properties of injection moulded plaques and significant enhancement in the fibrillation of LCP was observed in the moulded samples after addition of the compatibilizer. The effect of mould geometry was studied by comparing results obtained from three types of specimens, namely, specimens cut from large rectangular plaques, moulded rectangular bar specimens and molded dog-bone specimens. It was found that mould geometry had a direct influence on the magnitude of the elongational and shear stresses in the melt during molding and thus affected the degree of LCP fibrillation. Moreover, it was observed that the constriction at the “neck” of the dogbone geometry actually facilitated development of LCP fibre in the blend by increasing shear stress during moulding and promoting LCP fibre coalescence.

• Periodical: Key Engineering Materials (Volume 312)
• Pages: 133-138
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.312.133
• Online since: June 2006
• Authors: Lay Poh Tan, Chee Yoon Yue, K.C. Tam, Yee Cheong Lam, X. Hu
• Keywords: Compatibilizer, Fibrillation, Injection Molding, Liquid Crystalline Polymer, Mould Geometry

References

[1] G. Crevecouer and G. Groeninckx: Polym. Eng. Sci. Vol. 30 (1990), p.532.

[2] R.A. Weiss, W. Huh and L. Niclois: Polym. Eng. Sci. Vol. 27 (1987), p.684.

[3] G. Kiss: Polym. Eng. Sci. Vol. 27 (1987), p.410.

[4] B.R. Bassett and A.F. Yee: Polym. Composite Vol. 11 (1990), p.10.

[5] Y.S. Seo, S.M. Hong, S.S. Hwang, T.S. Park, U.K. Kim, S.M. Lee and J.L. Lee: Polymer Vol. 36 (1995), p.525. LCP phase Reduction in area, hence reduction in speed Fibre 1 Fibre 2 Fibre 1 + Fibre 2.

[6] S. C Tjong and Y.Z. Meng: Polym. Intern. Vol. 42 (1997), p.209.

[7] Q.W. Xu, H.C. Man and W.S. Lau: J. Mater. Proc. Tech, Vol. 63 (1997), p.519.

[8] D.R. Wiff and R.J. Weinert: Polymer Vol 39 (1998), p.5069.

[9] Q.H. Lin , J.Y. Jho, and A.F. Yee: Polym. Eng. Sci., Vol. 33 (1993), p.789.

[10] G.L. Chik, R.K.Y. Li and C.L. Choy: J. Materials Processing Tech Vol. 63 (1997), p.488.

[11] Golovoy, Kozlowski and Narkis : Polym. Eng. Sci. Vol. 32 (1992), p.854.

[12] L.P. Tan, C.Y. Yue, K.C. Tam, Y.C. Lam, X. Hu.: J. Appl. Poly Sci. Vol. 84 (2002), p.568.

[13] L.P. Tan, C.Y. Yue, K.C. Tam, Y.C. Lam, X. Hu.: J. Polym. Sci. Pt B: Polym. Phys. Vol. 41 (2003), p.2307.

[14] H.A. tone, B.J. Bentley and L.G. Leal: J. Fluid Mech. Vol. 173 (1986), p.131.

[15] H.A. Stone and L.G. Leal: J. Fluid Mech. Vol. 198 (1989), p.399.

[16] L.P. Tan, C.Y. Yue, K.C. Tam, Y.C. Lam and X. Hu: Polym. Int. Vol. 51 (2002), p.398.