Polylactic Acid /High-Ratio Natural Kenaf Fiber Biocomposite Sheets Processed by Calendering Melt Mixing Technique

Document Type : Research Article


Department of Mechanical Engineering, Isfahan University of Technology, Isfahan, Iran


Biodegradable polymers reinforced with cellulose-based natural fibers are of high strategic necessities toward the environment preservation acts. Numerous studies have reported the formulation of polylactic acid based bio-degradable micro-composites loaded with natural fibers. However, the use of high natural filler content has been shown to be an underlying challenge in terms of bio-based composites' processability. This study mainly aims at the processability of thermoplastic bio-degradable composites of polylactic acid/Kenaf using a two-roller calendering machine on the melt mixing manner assisted with high shear forces. The results indicated successful processing of the green composites containing 0-30 wt% of kenaf using the sheet forming process from direct mixing of kenaf and polylactic acid granules. It was shown that the tensile modulus increased by 130% and the density of the parts decreased by ~10% at the filler loading of 30 wt% with respect to the neat polylactic acid whilst the tensile strength decreased irrespective of the filler loading. The results further showed the melting temperature decreases supporting better processability by increasing the kenaf fraction. The crystallization against the decrease in the density was correlated to the decrease in the toughness of the parts. Moreover, the morphology and structural studies whilst supporting the changes in mechanical performance supported the effect of processing on the fillers orientation and the possible presence of agglomerated phase at higher filler loadings.


Main Subjects

[1] A. Ashori, Wood–plastic composites as promising green-composites for automotive industries!, Bioresour. Technol., 99(11) (2008) 4661-4667.
[2] D.J. Gardner, Y. Han, L. Wang, Wood–Plastic Composite Technology, Current Forestry Reports, 1(3) (2015) 139-150.
[3] G. Koronis, A. Silva, M. Fontul, Green composites: A review of adequate materials for automotive applications, Compos. B. Eng, 44(1) (2013) 120-127.
[4] E. Zini, M. Scandola, Green composites: an overview, Polym. Compos., 32(12) (2011) 1905-1915.
[5] R. Gunti, A. Ratna Prasad, A. Gupta, Mechanical and degradation properties of natural fiber‐reinforced PLA composites: Jute, sisal, and elephant grass, Polym. Compos., 39(4) (2018) 1125-1136.
[6] R.B. Yusoff, H. Takagi, A.N. Nakagaito, Tensile and flexural properties of polylactic acid-based hybrid green composites reinforced by kenaf, bamboo and coir fibers, Industrial Crops and Products, 94 (2016) 562-573.
[7] G.-L. Gavril, M. Wrona, A. Bertella, M. Świeca, M. Râpă, J. Salafranca, C. Nerín, Influence of medicinal and aromatic plants into risk assessment of a new bioactive packaging based on polylactic acid (PLA), Food Chem. Toxicol., 132 (2019) 110662.
[8] I.S. Tawakkal, M.J. Cran, S.W. Bigger, Effect of poly (lactic acid)/kenaf composites incorporated with thymol on the antimicrobial activity of processed meat, Journal of Food Processing and Preservation, 41(5) (2017) e13145.
[9] P.K. Bajpai, I. Singh, J. Madaan, Development and characterization of PLA-based green composites: A review, J. Thermoplast. Compos. Mater., 27(1) (2014) 52-81.
[10] N. Sarifuddin, H. Ismail, Z. Ahmad, The Effect of Kenaf Core Fibre Loading on Properties of Low Density Polyethylene/Thermoplastic Sago Starch/Kenaf Core Fiber Composites, Journal of Physical Science, 24(2) (2013).
[11] O. Seong, Han, M. Karevan, I.N. Sim, M. Bhuiyan, Y. Jang, J. Ghaffar, K. Kalaitzidou, Understanding the Reinforcing Mechanisms in Kenaf Fiber/PLA and Kenaf Fiber/PP Composites: A Comparative Study, International Journal of Polymer Science, 2012 (2012) 679252.
[12] H. Anuar, A. Zuraida, J. Kovacs, T. Tabi, Improvement of mechanical properties of injection-molded polylactic acid–kenaf fiber biocomposite, J. Thermoplast. Compos. Mater., 25(2) (2012) 153-164.
[13] I. Tharazi, A. Sulong, N. Muhamad, C. Haron, D. Tholibon, N. Ismail, M.M. Radzi, Z. Razak, Optimization of hot press parameters on tensile strength for unidirectional long kenaf fiber reinforced polylactic-acid composite, Procedia engineering, 184 (2017) 478-485.
[14] G. BEN, T. MATSUDA, Y. UENO, Development and mechanical properties of kenaf fibers green composites with pultrusion method, Journal of the Japan Society for Composite Materials, 36(2) (2010) 41-47.
[15] G.S. Mann, L.P. Singh, P. Kumar, S. Singh, Green composites: A review of processing technologies and recent applications, J. Thermoplast. Compos. Mater., 33(8) (2020) 1145-1171.
[16] A.U. Birnin-Yauri, N.A. Ibrahim, N. Zainuddin, K. Abdan, Y.Y. Then, B.W. Chieng, Effect of maleic anhydride-modified poly (lactic acid) on the properties of its hybrid fiber biocomposites, Polymers, 9(5) (2017) 165.
[17] I.S. Tawakkal, M.J. Cran, S.W. Bigger, Effect of kenaf fibre loading and thymol concentration on the mechanical and thermal properties of PLA/kenaf/thymol composites, Industrial Crops and Products, 61 (2014) 74-83.
[18] N.I.A. Razak, N.A. Ibrahim, N. Zainuddin, M. Rayung, W.Z. Saad, The influence of chemical surface modification of kenaf fiber using hydrogen peroxide on the mechanical properties of biodegradable kenaf fiber/poly (lactic acid) composites, Molecules, 19(3) (2014) 2957-2968.
[19] N. Graupner, J. Rößler, G. Ziegmann, J. Müssig, Fibre/matrix adhesion of cellulose fibres in PLA, PP and MAPP: a critical review of pull-out test, microbond test and single fibre fragmentation test results, Compos. - A: Appl. Sci. Manuf, 63 (2014) 133-148.
[20] M. Nematollahi, M. Karevan, P. Mosaddegh, M. Farzin, Morphology, thermal and mechanical properties of extruded injection molded kenaf fiber reinforced polypropylene composites, Materials Research Express, 6(9) (2019) 095409.
[21] M. Nematollahi, M. Karevan, M. Fallah, M. Farzin, Experimental and Numerical Study of the Critical Length of Short Kenaf Fiber Reinforced Polypropylene Composites, Fibers and Polymers, 21(4) (2020) 821-828.
[22] T.-J. Chung, J.-W. Park, H.-J. Lee, H.-J. Kwon, H.-J. Kim, Y.-K. Lee, W. Tai Yin Tze, The improvement of mechanical properties, thermal stability, and water absorption resistance of an eco-friendly PLA/kenaf biocomposite using acetylation, Applied Sciences, 8(3) (2018) 376.
[23] S. Jia, D. Yu, Y. Zhu, Z. Wang, L. Chen, L. Fu, Morphology, crystallization and thermal behaviors of PLA-based composites: wonderful effects of hybrid GO/PEG via dynamic impregnating, Polymers, 9(10) (2017) 528.
[24] A. Gao, Y. Zhao, Q. Yang, Y. Fu, L. Xue, Facile preparation of patterned petal-like PLA surfaces with tunable water micro-droplet adhesion properties based on stereo-complex co-crystallization from non-solvent induced phase separation processes, Journal of Materials Chemistry A, 4(31) (2016) 12058-12064.
[25] Z. Abdul Hamid, Surface Modification of Poly (lactic acid) (PLA) via Alkaline Hydrolysis Degradation, Advanced Materials Research, 970 (2014) 324-327.
[26] J.-M. Park, J.-Y. Choi, Z.-J. Wang, D.-J. Kwon, P.-S. Shin, S.-O. Moon, K.L. DeVries, Comparison of mechanical and interfacial properties of kenaf fiber before and after rice-washed water treatment, Compos. B. Eng, 83 (2015) 21-26.
[27] M.S. Huda, L.T. Drzal, A.K. Mohanty, M. Misra, Effect of fiber surface-treatments on the properties of laminated biocomposites from poly (lactic acid)(PLA) and kenaf fibers, Compos. Sci. Technol., 68(2) (2008) 424-432.
[28] H. Anuar, A. Zuraida, Thermal properties of injection moulded polylactic acid–kenaf fibre biocomposite, Malaysian Polymer J, 6(1) (2011) 51-57.
[29] G. Papageorgiou, D. Achilias, S. Nanaki, T. Beslikas, D. Bikiaris, PLA nanocomposites: Effect of filler type on non-isothermal crystallization, Thermochim. Acta, 511(1-2) (2010) 129-139.
[30] D. Wu, L. Wu, L. Wu, B. Xu, Y. Zhang, M. Zhang, Nonisothermal cold crystallization behavior and kinetics of polylactide/clay nanocomposites, J. Polym. Sci., Part B: Polym. Phys., 45(9) (2007) 1100-1113.
[31] P.-Y. Chen, H.-Y. Lian, Y.-F. Shih, S.-M. Chen-Wei, R.-J. Jeng, Preparation, characterization and crystallization kinetics of Kenaf fiber/multi-walled carbon nanotube/polylactic acid (PLA) green composites, Mater. Chem. Phys., 196 (2017) 249-255.
[32] S.O. Han, M. Karevan, I.N. Sim, M.A. Bhuiyan, Y.H. Jang, J. Ghaffar, K. Kalaitzidou, Understanding the reinforcing mechanisms in kenaf fiber/PLA and kenaf fiber/PP composites: A comparative study, International Journal of Polymer Science, 2012 (2012).
[33] R. Qiao, H. Deng, K.W. Putz, L.C. Brinson, Effect of particle agglomeration and interphase on the glass transition temperature of polymer nanocomposites, J. Polym. Sci., Part B: Polym. Phys., 49(10) (2011) 740-748.
[34] J. Seiler, J. Kindersberger, Insight into the interphase in polymer nanocomposites, IEEE Trans Dielectr Electr Insul, 21(2) (2014) 537-547.
[35] O.K.C. Tsui, T.P. Russell, C.J. Hawker, Effect of interfacial interactions on the glass transition of polymer thin films, Macromolecules, 34(16) (2001) 5535-5539.
[36] W. Zhao, Y. Su, X. Gao, J. Xu, D. Wang, Interfacial effect on confined crystallization of poly (ethylene oxide)/silica composites, J. Polym. Sci., Part B: Polym. Phys., 54(3) (2016) 414-423.
[37] Z. Tang, C. Zhang, X. Liu, J. Zhu, The crystallization behavior and mechanical properties of polylactic acid in the presence of a crystal nucleating agent, J. Appl. Polym. Sci., 125(2) (2012) 1108-1115.
[38] J. Feng, S.R. Venna, D.P. Hopkinson, Interactions at the interface of polymer matrix-filler particle composites, Polymer, 103 (2016) 189-195.
[39] F. Jones, A review of interphase formation and design in fibre-reinforced composites, J. Adhes. Sci. Technol., 24(1) (2010) 171-202.
[40] S.H. Ghaffar, O.A. Madyan, M. Fan, J. Corker, The influence of additives on the interfacial bonding mechanisms between natural fibre and biopolymer composites, Macromolecular Research, 26(10) (2018) 851-863.
[41] A. Hassan, M.M. Isa, Z.M. Ishak, N. Ishak, N.A. Rahman, F.M. Salleh, Characterization of sodium hydroxide-treated kenaf fibres for biodegradable composite application, High Perform. Polym., 30(8) (2018) 890-899.
[42] N. Saba, M. Paridah, M. Jawaid, Mechanical properties of kenaf fibre reinforced polymer composite: A review, Construction and Building materials, 76 (2015) 87-96.
[43] Y. Zare, K.Y. Rhee, D. Hui, Influences of nanoparticles aggregation/agglomeration on the interfacial/interphase and tensile properties of nanocomposites, Compos. B. Eng, 122 (2017) 41-46.