an official journal of: published by:
an official journal of: published by:
Editor in Chief: RAFFAELLO COSSU


  • Vesna Žepič Bogataj - Slovenian Tool and Die Development Centre, TECOS, Slovenia
  • Peter Fajs - Slovenian Tool and Die Development Centre, TECOS, Slovenia
  • Carolina Peñalva - AITIIP Centro Tecnológico, Spain
  • Marko Omahen - OMAPLAST, Slovenia
  • Matjaž Čop - ADRIA Mobil, Slovenia
  • Ari Henttonen - ECOPULP Finland Oy, Finland

Released under CC BY-NC-ND

Copyright: © 2019 CISA Publisher


This work investigates the feasibility of using the recycled polypropylene (rPP), cellulose (CF) and newsprint (NP) fibres in polyolefin reinforced composites. Recycled PP filled with 40 wt.% of cellulose (rPP/CF) or newsprint (rPP/NP), with the addition of impact modifier (IM) and compatibilizing agent (CA), have been prepared with extrusion melting and injection moulding. Melting and crystallization behaviour of plain matrix and composites were measured by differential scanning calorimetry (DSC). Morphological and mechanical properties were also studied using scanning electron microscope (SEM) and tensile testing, respectively. Thermal stability of composites was similar to neat rPP for both types of the filler used. Though, the crystallinity was progressively decreased with the addition of CF or NP. The DSC further revealed an occurrence of the two distinct melting transitions, meaning that the examined materials were not based on pure polypropylene (PP), but are rather blends of high-density polyethylene (HDPE) and PP, what has been confirmed also by the Fourier transform infrared spectroscopy (FTIR). The largest single source of contaminations in recycled PP comes from HDPE since both polymers are identified by a similar density and can be accidentally mixed during the conventional physical separation process. Composites reinforced with CF have shown better mechanical performances than those based on reclaimed NP fibres, what can be attributed to the initial fibre quality. Tensile strength of the composites filled with CF and NP fibres was 36 MPa and 29 MPa, respectively, in disparity to 23 MPa measured for neat rPP. The fibre addition further resulted in substantial increase in Young modulus of the composites. The addition of CF and NP fibres lead to an improved modulus of elasticity by 16 and 47%, respectively. Waste paper in the form of recovered cellulose or reclaimed newsprint fibre can thus meet all the technical requirements to become an alternative to inorganic fillers in thermoplastic composites.


Editorial History

  • Received: 01 Jul 2019
  • Revised: 18 Sep 2019
  • Accepted: 20 Sep 2019
  • Available online: 26 Sep 2019


Ashori, A., Nourbakhsh, A. 2008. A comparative study on mechanical properties and water absorption behavior of fiber-reinforced polypropylene composites prepared by OCC fiber and aspen fiber. Polym. Compos., 29:574–78

Backström, M., Fellers, C., and Htun, M. 1999. The influence of kappa number and surface energy on paper-to-paper friction. Nord. Pulp Pap. Res. J., 14(3): 204-208

Camacho, W., Karlsson, S. 2001. NIR, DSC, and FTIR as quantitative methods for compositional analysis of blends of polymers obtained from recycled mixed plastic waste. Polym Eng Sci, 41: 1626-1635

EC (2015). Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions, Closing the loop – An EU action plan for the Circular Economy, COM. 2015, 614 final, Brussels/BE, 2 December 2015

EMF and McKinsey. 2015. Growth within: a circular economy vision for a competitive Europe, Ellen MacArthur Foundation and McKinsey Center for Business and Environment: 126

European Paper Recycling Council (EPRC) monitoring report. 2017. European Declaration on Paper Recycling 2016-2020. Available at

Gregersen, Ø.W., Skinnarland, I., Johnsen, P.O., et al. 1995. Qualitative Methods for the Study of Lignin Distribution in Wood and Surface layers of unbleached Pulp fibers and Paper. J. Pulp Pap. Sci., 21(8): 285-287

Holbery, J., Houston, D. 2006. Natural-fiber-reinforced polymer composites inautomotive applications. JOM, 58(11):80

Jariwala, H., Jain, P. 2019. A review on mechanical behavior of natural fiber reinforced polymer composites and its applications. Journal of Reinforced Plastics and Composites, 38 (10): 441-453

Kalia, S., Kaith, B.S., Kaur, I. 2011. Cellulose Fibers: Bio- and Nano-Polymer Composites, Green Chemistry and Technology. Springer, Heidelberg/Dordrecht/London/New York, 2011

Kibblewhite R.P. 1983. The fibers of radiata pine mechanical pulps. Appita J., 36(4): 272

Kowaluk G. 2017. Lignocellulosic Fibers Composites: An Overview, Handbook of Composites from Renewable Materials, 293-308

Kumar, A., Choudhary, V., Khanna, R., Cayumil, R., Ikram-ul-Haq, M., Sahajwalla, V., Kumar, I. Angadi, S., E. Paruthy, G., S. Mukherjee, P., Park, M. 2017. Recycling polymeric waste from electronic and automotive sectors into value added products. Frontiers of Environmental Science & Engineering, 11(5):4

LIFE17 ENV/SI/000119. Implementation of a new Circular Economy through the valorisation of postconsumer PLAstic waste and reclaimed pulp FIBer.

Lin, J.H., Pan, Y.J., Liu, C.F., Huang, C.L., Hsieh, C.T., Chen, C.K., Lin, Z.Y. and Lou, C.W. (2015) Preparation and Compatibility Evaluation of Polypropylene/High Density Polyethylene Poly-blends. Materials, 8, 8850-8859

Lopez-Manchado, M., Biagiotti, J., Torre, L., Kenny, J. 2000. Effects of reinforcing fibers on the crystallization of polypropylene. Polymer Engineering and Science, 40:2194-2204

Mochane, M.J., Mokhena, T.C., Mokhothu, T.H., 2019. Recent progress on natural fiber hybrid composites for advanced applications: A review. eXPRESS Polymer Letters, 13 (2), 159–198

PlasticsEurope. 2018. Plastics – the Facts 2018. PlasticsEurope-Association of Plastic Makers. Available at

Shen, Li., and Ernst Worrell. 2014. Plastic Recycling. In Handbook of recycling: State-of-the-art for practitioners, analysts, and scientists. Edited by Ernst Worrell and Markus A. Reuter, 179–90. Amsterdam [etc.]: Elsevier

Sichina, W.J. 2000. Characterization of the quality of recycled polymers using DSC. Perkin Elmer Instruments

Sydow, Z., Bieńczak, K. 2018. The overview on the use of natural fibers reinforced composites for food packaging. Journal of Natural Fibers, 00(00), 1–12

TN 48 Polymer Heats of Fusion. TA Instruments, 23

Wunderlich, B. 1990. Thermal Analysis, 417–431, Academic Press, USA, 1990

Yang, H.-S., Kim, H.-J., Park, H.-J., Lee, B.-J., and Hwang, T.-S. 2007. Effect of compatibilizing agents on rice-husk flour reinforced polypropylene composites. Composite Structures, 77(1): 45–55

Žepič, V., Poljanšek, I., Oven, P., Čop, M. 2016. COST-FP1105: Properties of PLA films reinforced with unmodified and acetylated freeze dried nanofibrillated cellulose. Holzforschung, 70:1125–1134