Hygrothermal effect on moisture kinetics and mechanical properties of hemp/polypropylene composite: Experimental and numerical studies

• Published in: Polymer composites 2016-08, Vol.37 (8), p.2342-2352
• Main Authors: Toubal, Lotfi, Cuillière, Jean-Christophe, Bensalem, Karim, Francois, Vincent, Gning, Papa-Birame
• Format: Article
• Language: English
• Subjects: Absorption; Finite element method; Mathematical analysis; Mathematical models; Mechanical properties; Moisture; Polymer matrix composites; Polypropylenes
• ISSN: 0272-8397; 1548-0569
• DOI: 10.1002/pc.23414

The exposition of thermoplastic composites reinforced with natural fibers to moisture and heat is likely to lower their mechanical properties and restrain their use in the design of parts. The present work is focussed on investigating the effects of hygrothermal aging on the mechanical behaviour of injected polypropylene reinforced with short hemp fibers. Moreover, the kinetic of isothermal moisture absorption has been studied for four immersion temperatures. The experimental results show that the time taken to reach saturation decreases significantly with increase in immersion temperature. These tests also reveal that moisture absorption in this type of materials does not follow Fick's law. Thus, a new model is proposed to predict this behaviour by the use of a variable coefficient of diffusion. This model is implemented using both analytical and finite element analysis (FEA) approaches. The results obtained with this new model show a very good correlation between experimental, analytical, and FEA absorption curves. POLYM. COMPOS., 37:2342–2352, 2016. © 2015 Society of Plastics Engineers