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Licensed Unlicensed Requires Authentication Published by De Gruyter February 20, 2017

Extrusion Blow Molding of Polymeric Blends Based on Thermotropic Liquid Crystalline Polymer and High Density Polyethylene

  • C. Qian , C. D. Mansfield and D. G. Baird

Abstract

This work is concerned with the extrusion blow molding of polymeric blends containing thermotropic liquid crystalline polymer (TLCP) and high density polyethylene (HDPE), using a single screw extruder. The TLCP is synthesized from terephthalic acid, 4-hydroxybenzoic acid, hydroquinone and hydroquinone derivatives, the melting point of which is 280 °C. Because the TLCP is usually processed at much higher temperatures than HDPE, the thermal stability of HDPE at elevated temperature is evaluated. It is shown that HDPE is relatively stable in the processing temperature range of the TLCP used in this work (260 to 300 °C). Bottles are successfully produced from the blends containing 10, 20 and 50 wt% TLCP. The TLCP/HDPE blend bottles exhibit enhanced modulus relative to pure HDPE. However, the improvement in tensile strength is marginal. At 10 and 20 wt% TLCP contents, the TLCP phase exists as platelets aligning along the machine direction, while a co-continuous morphology is observed for the blend containing 50 wt% TLCP. To further enhance the mechanical properties of the blends, the preliminary effectiveness of maleic anhydride grafted HDPE (MA-g-HDPE) as a compatibilizer is studied. The injection molded ternary blends of TLCP/HDPE/MA-g-HDPE have demonstrated superior mechanical properties over the binary TLCP/HDPE blends, which suggests MA-g-HDPE as a potential compatibilizer for developing high performance TLCP/HDPE containers with enhanced mechanical properties.


*Correspondence address, Mail address: Donald G. Baird, Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA, E-mail:

References

Beekmans, F., Gotsis, A. D. and Norder, B., “Transient and Steady-State Rheological Behavior of the Thermotropic Liquid Crystalline Polymer Vectra B950”, J. Rheol., 40, 947966 (1996) 10.1122/1.550788Search in Google Scholar

Bualek-Limcharoen, S., Samran, J., Amornsakchai, T. and MeesiriW., “Effect of Compatibilizers on Mechanical Properties and Morphology of In-Situ Composite Film of Thermotropic Liquid Crystalline Polymer/Polypropylene”, Polym. Eng. Sci., 39, 312320 (1999) 10.1002/pen.11417Search in Google Scholar

Chinsirikul, W., Hsu, T. C. and Harrison, I. R., “Liquid Crystalline Polymer (LCP) Reinforced Polyethylene Blend Blown Film: Effects of Counter-Rotating Die on Fiber Orientation and Film Properties”, Polym Eng Sci., 36, 27082717 (1996a) 10.1002/pen.10670Search in Google Scholar

Chinsirikul, W., Hsu, T. C. and Harrison, I. R., “Liquid Crystalline Polymer (LCP) Reinforced Polyethylene Blend Blown Film: Effects of Counter-Rotating Die on Fiber Orientation and Film Properties”, Polym. Eng. Sci., 36, 27082717 (1996b) 10.1002/pen.10670Search in Google Scholar

Chiou, Y.-P., Chiou, K.-C. and Chang, F.-C., “In situ Compatibilized Polypropylene/Liquid Crystalline Polymer Blends”, Polymer, 37, 40994106 (1996) 10.1016/0032-3861(96)00247-9Search in Google Scholar

Crevecoeur, G., Groeninckx, G., “Morphology and Mechanical Properties of Thermoplastic Composites Containing a Thermotropic Liquid Crystalline Polymer”, Polym. Eng. Sci., 30, 53242 (1990) 10.1002/pen.760300906Search in Google Scholar

Datta, A., Baird, D. G., “Compatibilization of Thermoplastic Composites Based on Blends of Polypropylene with Two Liquid Crystalline Polymers”, Polymer, 36, 505514 (1995) 10.1016/0032-3861(95)91559-PSearch in Google Scholar

Datta, A., Chen, H. H. and Baird, D. G., “The Effect of Compatibilization on Blends of Polypropylene with a Liquid-Crystalline Polymer”, Polymer, 34, 75966 (1993) 10.1016/0032-3861(93)90360-MSearch in Google Scholar

Dutta, D., Fruitwala, H., Kohli, A. and WeissR.A., “Polymer Blends Containing Liquid Crystals: A Review”, Polym. Eng. Sci., 30, 10051018 (1990) 10.1002/pen.760301704Search in Google Scholar

Epacher, E., Tolveth, J., StollK. and Pukanszky, B., “Two-Step Degradation of High-Density Polyethylene during Multiple Extrusion”, J. Appl. Polym. Sci., 74, 15961605 (1999) 10.1002/(SICI)1097-4628(19991107)74:6<1596::AID-APP35>3.0.CO;2-DSearch in Google Scholar

Gotsis, A. D., Baird, D. G., “Rheological Properties of Liquid Crystalline Copolyester Melts. II. Comparison of Capillary and Rotary Rheometer Results”, J. Rheol., 29, 539556 (1985) 10.1122/1.549830Search in Google Scholar

Guo, T., Harrison, G. M. and Ogale, A. A., “Transient Shear Rheology and Rheo-Optical Microstructural Characterization of a Thermotropic Liquid Crystalline Polymer”, Polym. Eng. Sci., 45, 187197 (2005) 10.1002/pen.20265Search in Google Scholar

Handlos, A. A., Baird, D. G., “Processing and Associated Properties of in situ Composites Based on Thermotropic Liquid Crystalline Polymers and Thermoplastics”, J. Macromol. Sci. Polymer Rev., C35, 183238 (1995) 10.1080/15321799508009637Search in Google Scholar

Harlin, A., Vainio, T., “Effect of Polydispersity on the Thermomechanical Degradation of High-Density Polyethylene Polymerized Using a Chromium Catalyst”, Polym. Degrad. Stab., 39, 2934 (1993) 10.1016/0141-3910(93)90121-XSearch in Google Scholar

Heino, M. T., Hietaoja, P. T., Vainio, T. P. and Seppälä, J. V., “Effect of Viscosity Ratio and Processing Conditions on the Morphology of Blends of Liquid Crystalline Polymer and Polypropylene”, J. Appl. Polym. Sci., 51, 259270 (1994) 10.1002/app.1994.070510208Search in Google Scholar

Heino, M. T., Seppälä, J. V., “Extruded Blends of a Thermotropic Liquid Crystalline Polymer with Polyethylene Terephthalate, Polypropylene, and Polyphenylene Sulfide”, J. Appl. Polym. Sci., 44, 21852195 (1992) 10.1002/app.1992.070441215Search in Google Scholar

Heino, M. T., Seppälä, J. V., “Studies on Compatibilization of Blends of Polypropylene and a Thermotropic Liquid Crystalline Polymer”, J. Appl. Polym. Sci., 48, 16771687 (1993) 10.1002/app.1993.070480918Search in Google Scholar

Hsu, T. C., Lichkus, A. M. and Harrison, I. R., “Liquid Crystal Polymer/Polyethylene Blends for Thin Film Applications”, Polym. Eng. Sci., 33, 860863 (1993) 10.1002/pen.760331311Search in Google Scholar

Isayev, A. I., Subramanian, P. R., “Blends of a Liquid-Crystalline Polymer with Poly(ether ether ketone)”, Polym. Eng. Sci., 32, 8593 (1992) 10.1002/pen.760320203Search in Google Scholar

Jang, S. H., Kim, B. S., “Morphology and Mechanical Properties of Liquid Crystalline Copolyester and Poly(eEthylene 2,6-naphthalate) Blends”, Polym. Eng. Sci., 35, 53845 (1995) 10.1002/pen.760350611Search in Google Scholar

Kiss, G., “In situ Composites: Blends of Isotropic Polymers and Thermotropic Liquid Crystalline Polymers”, Polym. Eng. Sci., 27, 410423 (1987) 10.1002/pen.760270606Search in Google Scholar

Krishnaswamy, R. K., Wadud, S. E. B. and Baird, D. G., “Influence of a Reactive Terpolymer on the Properties of in situ Composites Based on Polyamides and Thermotropic Liquid Crystalline Polyesters”, Polymer, 40, 701716 (1998) 10.1016/S0032-3861(98)00257-2Search in Google Scholar

Langelaan, H. C., Gotsis, A. D., “The Relaxation of Shear and Normal Stresses of Nematic Liquid Crystalline Polymers in Squeezing and Shear Flows”, J. Rheol., 40, 107129 (1996) 10.1122/1.550733Search in Google Scholar

Machiels, A. G. C., Denys, K. F. J., DamJ.V. and De Boer, A. P., “Effect of Processing History on the Morphology and Properties of Polypropylene/Thermotropic Liquid Crystalline Polymer Blends”, Polym. Eng. Sci., 37, 5972 (1997) 10.1002/pen.11645Search in Google Scholar

Mcgrady, C. D., “Linking Rheological and Processing Behavior to Molecular Structure in Sparsely-Branched Polyethylenes Using Constitutive Relationships”, PhD Dissertation, Virginia Tech, Blacksburg (2009)Search in Google Scholar

Mcleod, M. A., Baird, D. G., “The Crystallization Behavior of Blends of Thermotropic Liquid Crystalline Polymers”, Polymer, 40, 37433752 (1999) 10.1016/S0032-3861(98)00592-8Search in Google Scholar

Meng, Y. Z., Tjong, S. C., “Preparation and Properties of Injection-Molded Blends of Poly(vinyl chloride) and Liquid Crystal Copolyester”, Polymer, 40, 27112718 (1999) 10.1016/S0032-3861(98)00507-2Search in Google Scholar

O’Donnell, H. J., Baird, D. G., “In situ Reinforcement of Polypropylene with Liquid-Crystalline Polymers: Effect of Maleic Anhydride-Grafted Polypropylene”, Polymer, 36, 31133126 (1995) 10.1016/0032-3861(95)97874-FSearch in Google Scholar

Postema, A. R., Fennis, P. J., “Preparation and Properties of Self-Reinforced Polypropylene/Liquid Crystalline Polymer Blends”, Polymer, 38, 55575564 (1997) 10.1016/S0032-3861(97)00099-2Search in Google Scholar

Qian, C., “Connecting the Rheological Behavior to the Processing of Thermotropic Liquid Crystalline Polymers in the Super-Cooled State”, PhD Dissertation, Virginia Tech, Blacksburg (2016)10.1016/j.polymer.2016.08.056Search in Google Scholar

Sabol, E. A., Handlos, A. A. and Baird, D. G., “Composites Based on Drawn Strands of Thermotropic Liquid Crystalline Polymer Reinforced Polypropylene”, Polym. Compos., 16, 330345 (1995) 10.1002/pc.750160411Search in Google Scholar

Saengsuwan, S., Bualek-Limcharoen, S., Mitchell, G. R. and OlleyR.H., “Thermotropic Liquid Crystalline Polymer (Rodrun LC5000)/Polypropylene in situ Composite Films: Rheology, Morphology, Molecular Orientation and Tensile Properties”, Polymer, 44, 34073415 (2003) 10.1016/S0032-3861(03)00244-1Search in Google Scholar

Seppälä, J., Heino, M. and Kapanen, C., “Injection-Moulded Blends of a Thermotropic Liquid Crystalline Polymer with Polyethylene Terephthalate, Polypropylene, and Polyphenylene Sulfide”, J. Appl. Polym. Sci., 44, 10511060 (1992) 10.1002/app.1992.070440614Search in Google Scholar

Son, Y., Weiss, R. A., “Compatibilizers for Thermotropic Liquid Crystalline Polymer/Polyolefin Blends Prepared by Reactive Mixing: The Effect of Processing Conditions”, Polym. Eng. Sci., 41, 329340 (2001) 10.1002/pen.10732Search in Google Scholar

Son, Y., Weiss, R. A., “Compatibilizers for Thermotropic Liquid Crystalline Polymer/Polyethylene Blends Prepared by Reactive Mixing”, Polym. Eng. Sci., 42, 13221332 (2002) 10.1002/pen.11034Search in Google Scholar

Sukhadia, A. M., Datta, A. and Baird, D. G., “Mixing History on the Morphology and Properties of Thermoplastic/LCP Blends”, Int. Polym. Proc., 7, 21828 (1992) 10.3139/217.920218Search in Google Scholar

Yan, D., Wang, W. J. and Zhu, S., “Effect of Long Chain Branching on Rheological Properties of Metallocene Polyethylene”, Polymer, 40, 17371744 (1998) 10.1016/S0032-3861(98)00318-8Search in Google Scholar

Zhang, H., Weiss, R. A., Kuder, J. E. and Cangiano, D., “Reactive Compatibilization of Blends Containing Liquid Crystalline Polymers”, Polymer, 41, 30693082 (2000) 10.1016/S0032-3861(99)00469-3Search in Google Scholar

Zhuang, P., Kyu, T. and White, J. L., “Characteristics of Hydroxybenzoic Acid-Ethylene Terephthalate Copolymers and their Blends with Polystyrene, Polycarbonate, and Polyethylene Terephthalate”, Polym. Eng. Sci., 28, 1095106 (1988) 10.1002/pen.760281704Search in Google Scholar

Received: 2016-04-29
Accepted: 2016-06-27
Published Online: 2017-02-20
Published in Print: 2017-03-03

© 2017, Carl Hanser Verlag, Munich

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