• Cristiano Fragassa Department of Industrial Engineering, University of Bologna Viale del Risorgimento 2, 40136 Bologna, Italy
  • Carlo Santulli School of Architecture and Design, University of Camerino, via Paolo Emilio 28, 00192 Roma, Italy
  • Ana Pavlović Department of Industrial Engineering, University of Bologna Viale del Risorgimento 2, 40136 Bologna, Italy
  • Milan Šljivić Mechanical Engineering, University of Banja Luka, Stepe Stepanovica 71, 78000 Banja Luka, Republic of Srpska, Bosnia & Herzegovina



A growing concern over environmental issues and the common interest to find a viable alternative to the use of glass or carbon composite reinforcements has led to an increased attention in ecologically sustainable polymer composites. These „green” materials are made by natural fibers, as reinforcement, filled with natural-organic fillers, i.e. derived from renewable or biodegradable sources. At the same time, this relatively new class of materials faces several limits in comparison to traditional composites especially regarding the properties of resistance. This paper investigates the advantages of use of combination of natural fibers for improving mechanical proprieties of „green” composite materials. At the moment, the prevailing opinion is that green composites are not usable in structural applications, and, as a consequence, have to be relegated to unworthy applications (as fillers). On the contrary, there are several evidences that mixing different natural fibers (in practice usually called „hybridization”) leads to an improvement of these material properties. Although usually quite limited in terms of percentage, these improvements from time to time allow a new enlargement in the fields of applications for green composites. Following a large state-of-the-art on green composites, including potential benefits and limits of these materials, the paper proposes several examples of hybridization showing its effect on mechanical proprieties.


[1] R. A. Clark, M. P. Ansell, Jute and glass fibre hybrid laminates, J Mater Sci., Vol. 21 (1986) 269–276.

[2] M. Ramesh, K. Palanikumar, K. Hema-chandra Reddy, Mechanical property evaluation of sisal–jute–glass fiber reinforced polyester composites, Composites Part B: Engineering, Vol. 48 (2013) 1–9.

[3] S. Öztürk, The effect of fibre content on the mechanical properties of hemp and basalt fibre reinforced phenol formaldehyde composites, J Mater Sci, Vol. 40 (2005) 4585–4592.

[4] I. M. de Rosa, C. Santulli, F. Sarasini, M. Valente, Effect of loading-unloading cycles on impact-damaged jute/glass hybrid laminates, Polym Compos, Vol. 30−12 (2009) 1879–1887.

[5] L. Devi, S. Bhagawan, K. Nair, S. Tho-mas, Water absorption behavior of PALF/GF hybrid polyester composites, Polym Compos, Vol. 32 (2011) 335–346.

[6] O. I. Benevolenski, J. Karger-Kocsis,
K. P. Mieck, T. Reubmann, Instrumented perforation impact response of polypropylene composites with hybrid reinforcement flax/glass and flax/cellulose fibers, J Thermoplast Compos Mater, Vol. 13 (2000) 481–496.

[7] H. M. Akil, I. M. de Rosa, C. Santulli,
F. Sarasini, Flexural behaviour of pultruded jute/glass and kenaf/glass hybrid composites monitored using acoustic emission, Mater Sci Eng A, Vol. 527 (2010) 2942–2950.

[8] J. Summerscales, A. Virk, W. Hall, Re-view of bast fibres and their composites: Part 3 – Modelling, Composites Part A, Vol. 44 (2013) 132−139.

[9] P. Wambua, J. Ivens, I. Verpoest, Natural fibres: can they replace glass in fibre reinforced plastics?, Compos Sci Technol, Vol. 63−9 (2003) 1259–1264.

[10] C. Santulli, M. Janssen, G. Jeronimidis, Partial replacement of E-glass fibres with flax fibres in composites and effect on falling weight impact performance, J Mater Sci, Vol. 40 (2005)

[11] J. H. S. Almeida Júnior, H. L. Ornaghi Júnior, S. C. Amico, F. D. R. Amado, Study of hybrid intralaminate curaua/glass composites, Mater Des, Vol. 42 (2012) 111–117.

[12] C. Santulli, Review. Impact properties of glass/plant fibre hybrid laminates, J Mater Sci, Vol. 42 (2007) 3699–3707.

[13] I. M. De Rosa, C. Santulli, F. Sarasini, M. Valente, Post-impact damage characterization of hybrid configurations of jute/glass polyester laminates using acoustic emission and IR thermography, Compos Sci Technol, Vol. 69 (2009) 1142–1150.

[14] G. Cicala, G. Cristaldi, G. Recca, G. Ziegmann, A. El-Sabbagh, M. Dickert, Properties and performances of various hybrid glass/natural fibre composites for curved pipes, Mater. Des. Vol. 30 (2009) 2538–2542.

[15] M. T. Majid Tehrani Dehkordi, H. No-sraty, M. M. Shokrieh, G. Minak, D. Ghelli, The influence of hybridization on impact damage behavior and residual compression strength of intraply basalt/nylon hybrid composites, Mater Des, Vol. 43 (2013) 283–290.

[16] M. T. Dehkordi, H. Nosraty, M. M. Shokrieh, G. Minak, D. Ghelli, Low velocity impact properties of intraply hybrid composites based on basalt and nylon, woven fabrics, Mater Des, Vol..31 (2010) 3835–3844.

[17] R. Petrucci, C. Santulli, D. Puglia, F. Sarasini, L. Torre, J.M. Kenny, Mechanical characterisation of hybrid composite laminates based on basalt fibres in combination with flax, hemp and glass fibres manufactured by vacuum infusion, Mater Des, Vol. 49 (2013) 728−735.

[18] H. N. Dhakal, F. Sarasini, C. Santulli, J. Tirillò, Z. Zhang, V. Arumugam, Effect of basalt fibre hybridisation on post-impact mechanical behaviour of hemp fibre reinforced composites, Composites Part A 75 (2015) 54−67.

[19] P. Amuthakkannan, V. Manikandan, J. T. W. Jappes, M. Uthayakumar, Influence of stacking sequence on mechanical properties of basalt–jute fiber- reinforced polymer hybrid composites, J Polym Eng, Vol. 32 (2012) 547–554

[20] C. Santulli, F. Sarasini, J. Tirillò, M. Valente, T. Valente, A.P. Caruso, M. Infantino, E. Nisini, G. Minak, Mechanical behavior of jute cloth/wool felts hybrid laminates, published online, Materials and Design, (2013), doi: 10.1016/j.matdes.2013.02.014.

[21] J. Sahari, S. M. Sapuan, Natural fiber reinforced biodegradable polymer composites, Rev. Adv. Mater. Sci., Vol. 30 (2011) 166−174.

[22] G. Bogoeva-Gaceva, M. Avella, et alt., Natural Fiber Eco-Composites, Polym. Compos., Vol. 28 (2007) 98–107.

[23] S. De Paola, C. Fragassa, G. Minak,
A. Pavlovic, Green Composites: a review of state of art, Proceedings of 30th Danubia Adria Symposium, Sept. 2013.

[24] A. Pavlovic, S. de Paola, C. Fragassa,
G. Minak, Mechanical characterization of green composites: earliest experimental evidences by flexural tests, Proceedings of 21th Composite/Nano Engineering (ICEE), 2013, 273−276.

[25] A. Hyseni, S. De Paola, G. Minak,
C. Fragassa, Mechanical characterization of eco-composites, Proceedings of 30th Danubia Adria Symposium, 2013, 145−148.