In Situ Reinforcement of PLA Using Nylon 6 in PLA/Nylon 6 Extrudate Blend via Twin-Screw Extrusion

Abstract:

This research was aimed to study the possibility of in-situ reinforcement of PLA by elongated Nylon 6 in PLA/Nylon 6 blend during elongating of PLA/Nylon extrusion. PLA was melt blending with Nylon 6 in a twin screw extruder with various compositions i.e. 5, 10, 15 and 20 % of Nylon 6. The extrudate was drawn after leaving extrusion orifice die of 3 mm in diameter, with the pulling speed of 12 cycles per minute. The extrudate gauge length 15 cm were used to perform tension test in order to investigate tensile properties. The blending between PLA and Nylon 6 with 11 phr of benzene sulfonamide (BSA), based on Nylon 6, as a plasticizer was also investigated at the same PLA/Nylon 6 blend ratios. The extrusion used conditions were also the same. Tension was also performed onto the extrudates with the gauge length 15 cm. Thermal degradation was also investigated. The SEM micrographs of blends in the longitudinal direction of PLA/Nylon 6 extrudate showed elongated of Nylon 6 in PLA matrix phase. The elongated of Nylon 6 phase in PLA matrix phase was found very clear in the plasticized blends. This phenomenon clearly occurred for the blends composition of both 95/5 and 90/10, with and without plasticizer. The results also showed that Young’s modulus of the blends with 5 % Nylon 6 was increased about 10 % whereas at 10 % nylon 6, the modulus was not significantly different from neat PLA. With the addition of plasticizer, nylon 6 was elongated more than that in the blend with un-plasticized Nylon 6. Due to the lack in interfacial adhesion, shown by SEM micrograph, tensile strength was found to be decreased. As expected, the elongation at break under tension was increased with the content of nylon 6. This was due to the toughening effect of elongated Nylon 6. Thermal stability, notified by degradation temperature of PLA, T_d, was found to be improved. This was due to the high thermal stability of nylon 6. The results from the research can inform that the elongated nylon 6 phase in PLA matrix can perform as fibrous reinforcement. At high content of nylon 6, i.e. 15 and 20 %, the elongation of nylon 6 was rather difficult due to the less matrix phase and low shearing between PLA and nylon 6. Phase compatibility improvement could be the factor to improve the in-situ reinforcement.

• Periodical: Key Engineering Materials (Volume 659)
• Pages: 428-435
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.659.428
• Online since: August 2015
• Authors: Chanchai Thongpin*, Kullanith Chaemprasith, Jakapan Teeralertpanich, Parisara Saensuk, Nontawat Kritape
• Keywords: Elongates Nylon 6 in PLA/Nylon 6 Extrudate, In Situ Reinforcement, Twin Screw Extrusion

References

[1] A. Awal, M. Rana and M. Sain, Thermorheological and mechanical properties of cellulose reinforced PLA bio-composites Mechanics of Materials, 80 (2015), 87-95.

DOI: 10.1016/j.mechmat.2014.09.009

[2] D. Notta-Cuvier, J. Odent, R. Delille, M. Murariu, F. Lauro, J.M. Raquez, B. Bennani, P. Dubois, Tailoring polylactide (PLA) properties for automotive applications: Effect of addition of designed additives on main mechanical properties, Polymer Testing, 36 (2014).

DOI: 10.1016/j.polymertesting.2014.03.007

[3] P. Stloukal, A. Kalendova, H. Mattausch, S. Laske, C. Holzer and M. Koutny, The influence of a hydrolysis-inhibiting additive on the degradation and biodegradation of PLA and its nanocomposites, Polymer Testing, 41 (2015) 124-132.

DOI: 10.1016/j.polymertesting.2014.10.015

[4] G. Gorrasi, C. Milone, E. Piperopoulos, M. Lanza and A. Sorrentino, Hybrid clay mineral-carbon nanotube-PLA nanocomposites films. Preparation and photodegradation effect on their mechanical, thermal and electrical properties, Applied Clay Science, 71 (2013).

DOI: 10.1016/j.clay.2012.11.004

[5] M. Stępień and Ł. Figiel , Morphology evolution and macroscopic behaviour of PLA-organoclay nanocomposites during extensional rheology: experimental study, Polymer Testing, Accepted Manuscript, Available online 9 January (2015).

DOI: 10.1016/j.polymertesting.2015.01.004

[6] X. Yi, L. Xu, Y.L. Wang, G.J. Zhong, X. Ji, and Z.M. Li, Morphology and properties of isotactic polypropylene/poly(ethylene terephthalate) in situ microfibrillar reinforced blends: Influence of viscosity ratio, European Polymer Journal, 46 (2010).

DOI: 10.1016/j.eurpolymj.2009.12.027

[7] F.C. Pai, S.M. Lai and H.H. Chu, Characterization and Properties of Reactive Poly(lactic acid)/polyamide 610 Biomass Blends, Journal of Applied Polymer Science, (2013) 2563-2571.

DOI: 10.1002/app.39473

[8] A. Nuzzo, E. Bilotti, T. Peijs, D. Acierno and G. Filippone, Nanoparticle-induced co-continuity in immiscible polymer blends-A comparative study on biobased PLA-PA11 blends filled with organoclay, sepiolite, and carbon nanotubes, Polymer 55 (2014).

DOI: 10.1016/j.polymer.2014.07.036

[9] R. Patel, D.A. Ruehle, J.R. Dorgan, P. Halley and D. Martin, Biorenewable Blends of Polyamide-11 and Polylactide, Polymer Engineering and Science, (2014) 1523-1532.

DOI: 10.1002/pen.23692

[10] T.S. Ellis, Phase behavior of polyamide-polyester blends: the influence of aromaticity, Polymer, 38 (15) (1997) 3837-3841.

DOI: 10.1016/s0032-3861(96)00935-4

[11] T.M. Ting, M.M. Nasef and K. Hashim, Modification of nylon 6 fibers by radiation-induced graft polymerization of vinylbenzyl chloride, Radiation Physics and Chemistry, 109 (2015), 54-62.

DOI: 10.1016/j.radphyschem.2014.12.010

[12] J. Shen, M. Wang, J. Li and S. Guo, In situ fibrillation of polyamide 6 in istactic polypropylene occurring in the laminating-multiplying die, Polymer for advance technology, Vol. 22 (2), 2011 237-245.

DOI: 10.1002/pat.1525

[13] R.C. Willemse, A. P. de Boer, J. van Dam and A.D. Gotsis, Co-continuous morphologies in polymer blends: the influence of the interfacial tension, Polymer, 40 (1999) 827-834.

DOI: 10.1016/s0032-3861(98)00307-3

[14] Y. Deyrail, R. Fulchiron and P. Cassagnau, Morphology development in immiscible polymer blends during crystallization of dispersed phase under shear flow, Polymer, 43 (2002) 3311-3321.

DOI: 10.1016/s0032-3861(02)00134-9

[15] S.L. Yang, Z.H. Wu, W. Yang and M.B. Yang, Thermal and mechanical properties of chemical crosslinked polylactide (PLA), Polymer Testing, 27 (2008) 957-963.

DOI: 10.1016/j.polymertesting.2008.08.009

[16] C. Wan, Y. Zhang and Y. Zhang, Effect of alkyl quaternary ammonium on processing discoloration of melt-intercalated PVC-montmorillonite composites, Polymer Testing 23 (2004) 299–306.

DOI: 10.1016/j.polymertesting.2003.08.001