Journal of Polymers and the Environment

, Volume 27, Issue 5, pp 1096–1104 | Cite as

Compatibilizer Acidity in Coir-Reinforced PLA Composites: Matrix Degradation and Composite Properties

  • T. R. Rigolin
  • M. C. Takahashi
  • D. L. Kondo
  • S. H. P. BettiniEmail author
Original paper


Coir fibers are lignocellulosic fibers extracted from the outer husk of a coconut, known for their versatility and low cost. This study assessed the feasibility of producing coir reinforced poly(lactic acid) (PLA) composites and the use of maleic anhydride grafted PLA (PLA-g-MA) as compatibilizer. Composites were produced in a twin-screw extruder and the mechanical properties were evaluated by tensile, flexural and heat deflection temperature tests. The morphological properties were assessed by scanning electron microscopy (SEM). The effect of compatibilizer and fiber content on molar mass of the composites was assessed by means of size-exclusion chromatography. SEM images showed that addition of the compatibilizer improved interfacial adhesion. However, this finding was not reflected in the mechanical properties because the high acidity content of the compatibilizer, revealed by titration of acid groups, along with the residual moisture of the fibers, significantly decreased molar mass of the polymer, impairing the composite matrix properties.


PLA Coir fiber Composite Compatibilizer Degradation 



This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES)—Finance Code 001. The authors would like to thank Inbrasfama for the donation of coir fiber and the financial support by PPG-CEM.


  1. 1.
    Castro-Aguirre E, Iñiguez-Franco F, Samsudin H, Fang X, Auras R (2016) Poly(lactic acid)—mass production, processing, industrial applications, and end of life. Adv Drug Deliv Rev 107:333–366CrossRefGoogle Scholar
  2. 2.
    Wu C-S (2009) Renewable resource-based composites of recycled natural fibers and maleated polylactide bioplastic: characterization and biodegradability. Polym Degrad Stab 94:1076–1084CrossRefGoogle Scholar
  3. 3.
    Garlotta D (2001) A literature review of poly(lactic acid). J Polym Environ 9:63–84CrossRefGoogle Scholar
  4. 4.
    Auras R (2010) Poly(lactic acid) synthesis, structures, properties, processing, and applications. Wiley, HobokenCrossRefGoogle Scholar
  5. 5.
    Dammer L, Carus M, Raschka A, Scholz L (2013) Market developments of and opportunities for biobased products and chemicals. Nova-Institute for Ecology and Innovation, HürthGoogle Scholar
  6. 6.
    Dong Y, Ghataura A, Takagi H, Haroosh HJ, Nakagaito AN, Lau K-T (2014) Polylactic acid (PLA) biocomposites reinforced with coir fibres: evaluation of mechanical performance and multifunctional properties. Composites A 63:76–84CrossRefGoogle Scholar
  7. 7.
    Murariu M, Dubois P (2016) PLA composites: from production to properties. Adv Drug Deliv Rev 107:17–46CrossRefGoogle Scholar
  8. 8.
    Csikós Á, Faludi G, Domján A, Renner K, Móczó J, Pukánszky B (2015) Modification of interfacial adhesion with a functionalized polymer in PLA/wood composites. Eur Polym J 68:592–600CrossRefGoogle Scholar
  9. 9.
    Yussuf AA, Massoumi I, Hassan A (2010) Comparison of polylactic acid/kenaf and polylactic acid/rise husk composites: the influence of the natural fibers on the mechanical, thermal and biodegradability properties. J Polym Environ 18:422–429CrossRefGoogle Scholar
  10. 10.
    Gurunathan T, Mohanty S, Nayak SK (2015) A review of the recent developments in biocomposites based on natural fibres and their application perspectives. Composites A 77:1–25CrossRefGoogle Scholar
  11. 11.
    Pickering KL, Efendy MGA, Le TM (2016) A review of recent developments in natural fibre composites and their mechanical performance. Composites A 83:98–112CrossRefGoogle Scholar
  12. 12.
    Jang JY, Jeong TK, Oh HJ, Youn JR, Song YS (2012) Thermal stability and flammability of coconut fiber reinforced poly(lactic acid) composites. Composites B 43:2434–2438CrossRefGoogle Scholar
  13. 13.
    Tomczak F, Sydenstricker THD, Satyanarayana KG (2007) Studies on lignocellulosic fibers of Brazil. Part II: morphology and properties of Brazilian coconut fibers. Composites A 38:1710–1721CrossRefGoogle Scholar
  14. 14.
    Kulkarni AG, Satyanarayana KG, Sukumaran K, Rohatgi PK (1981) Mechanical behaviour of coir fibres under tensile load. J Mater Sci 16:905–914CrossRefGoogle Scholar
  15. 15.
    Mukherjee T, Kao NPLA (2011) Based biopolymer reinforced with natural fibre: a review. J Polym Environ 19:714–725CrossRefGoogle Scholar
  16. 16.
    Oksman K, Skrifvars M, Selin J-F (2003) Natural fibres as reinforcement in polylactic acid (PLA) composites. Compos Sci Technol 63:1317–1324CrossRefGoogle Scholar
  17. 17.
    Bax B, Müssig J (2008) Impact and tensile properties of PLA/Cordenka and PLA/flax composites. Compos Sci Technol 68:1601–1607CrossRefGoogle Scholar
  18. 18.
    Graupner N, Herrmann AS, Müssig J (2009) Natural and man-made cellulose fibre-reinforced poly(lactic acid) (PLA) composites: an overview about mechanical characteristics and application areas. Composites A 40:810–821CrossRefGoogle Scholar
  19. 19.
    Petinakis E, Yu L, Edward G, Dean K, Liu H, Scully AD (2009) Effect of matrix–particle interfacial adhesion on the mechanical properties of poly(lactic acid)/wood-flour micro-composites. J Polym Environ 17:83–94CrossRefGoogle Scholar
  20. 20.
    Lu T, Liu S, Jiang M, Xu X, Wang Y, Wang Z, Gou J, Hui D, Zhou Z (2014) Effects of modifications of bamboo cellulose fibers on the improved mechanical properties of cellulose reinforced poly(lactic acid) composites. Composites B 62:191–197CrossRefGoogle Scholar
  21. 21.
    Yu T, Hu C, Chen X, Li Y (2015) Effect of diisocyanates as compatibilizer on the properties of ramie/poly(lactic acid) (PLA) composites. Composites A 76:20–27CrossRefGoogle Scholar
  22. 22.
    Yu T, Jiang N, Li Y (2014) Study on short ramie fiber/poly(lactic acid) composites compatibilized by maleic anhydride. Composites A 64:139–146CrossRefGoogle Scholar
  23. 23.
    Carlson D, Nie L, Narayan R, Dubois P (1999) Maleation of polylactide (PLA) by reactive extrusion. J Appl Polym Sci 72:477–485CrossRefGoogle Scholar
  24. 24.
    Detyothin S, Selke SEM, Narayan R, Rubino M, Auras R (2013) Reactive functionalization of poly(lactic acid), PLA: effects of the reactive modifier, initiator and processing conditions on the final grafted maleic anhydride content and molecular weight of PLA. Polym Degrad Stab 98:2697–2708CrossRefGoogle Scholar
  25. 25.
    Lucas N, Bienaime C, Belloy C, Queneudec M, Silvestre F, Nava-Saucedo J-E (2008) Polymer biodegradation: mechanisms and estimation techniques—a review. Chemosphere 73, 429–442CrossRefGoogle Scholar
  26. 26.
    Bettini SHP, Antunes MC, Magnabosco R (2011) Investigation on the effect of a compatibilizer on the fatigue behavior of PP/coir fiber composites. Polym Eng Sci 51:2184–2190CrossRefGoogle Scholar
  27. 27.
    Rigolin TR, Costa LC, Chinelatto MA, Muñoz PAR, Bettini, SHP (2017) Chemical modification of poly(lactic acid) and its use as matrix in poly(lactic acid) poly(butylene adipate-co-terephthalate) blends. Polym Test 63:542–549CrossRefGoogle Scholar
  28. 28.
    Chawla KK (2012) Composite materials; Springer New YorkCrossRefGoogle Scholar
  29. 29.
    Takahashi MC, Rigolin TR, Kondo DL, Bettini SHP (2017) Compatibilização de compósitos de PLA e fibra de coco via inserção do PLA quimicamente modificado com anidrido maleico, por extrusão reativa in Congr. Bras. Polímeros. Águas de Lindóia, October, 2017, pp 2229–2233Google Scholar

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© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of Materials EngineeringUniversidade Federal de São CarlosSão CarlosBrazil

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