Performance of long Canadian natural fibers as reinforcements in polymers

Abstract

Fiber morphology has a significant effect on the mechanical properties of fiber/polymer composites. The performance of nine types of long wood fibers (initial aspect ratio of >40), two long agricultural fibers (initial aspect ratio of >40), and one short fiber wood flour (initial aspect ratio of ¼ 5-10) are compared. The fibers were compounded in polypropylene in a Brabender mixer and subsequently injection molded. The longer natural fibers (both wood fibers and agricultural fibers) did not provide significant additional reinforcement when compared to the wood flour. The fibers were extracted from the final specimens and measured using a Fiber Quality Analyzer. They were found to be severely degraded by processing, while the wood flour morphology was only slightly modified. The degree of length degradation was found to be dependent on fiber strength.

A Review of the Impact Performance of Natural Fiber Thermoplastic Composites

“…However, a negative correlation between fiber content and NI strength has also been reported in other many NFTC studies (Li et al, 2001(Li et al, , 2012Marcovich and Villar, 2003;Yang et al, 2006;Czél and Kanyok, 2007;Ashori et al, 2008;He et al, 2008;Nourbakhsh and Ashori, 2008;Yao et al, 2008;Liu et al, 2009;Guo et al, 2010). The reasons proposed for this included: 1) a change in the nature of the fracture from ductile to brittle reduction of the deformability of the polymer (Mohanty and Nayak, 2010).…”

“…The increase of NFTC NI strength by the addition of compatibilizer has been observed in several studies (Sanadi et al, 1994(Sanadi et al, , 1999Karnani et al, 1997;Feng et al, 2001;Li et al, 2001;Lei et al, 2007;Ashori et al, 2008;Beg and Pickering, 2008;Lee et al, 2009;Araujo et al, 2010;Guo et al, 2010;Mohanty and Nayak, 2010;Paul et al, 2010;Malfatti et al, 2017). This is often related to an increase in the fiber-matrix adhesion/compatibility, which leads to higher energy required for crack propagation (Feng et al, 2001;Marcovich and Villar, 2003;Ashori et al, 2008).…”

“…Due to differences in the nature of matrix materials, fibers, test conditions and number of fiber contents examined, the task of drawing conclusions or general statements from the above information is certainly challenging. Regarding the NI strength, which is related to the crack propagation phenomenon, a positive correlation between fiber content and NI strength has been observed in several studies (Rana et al, 1998;Garkhail et al, 2000;Jayaraman, 2003;Singleton et al, 2003;Mohanty et al, 2004aMohanty et al, ,b, 2006Bledzki et al, 2007Bledzki et al, , 2009Bax and Müssig, 2008;Khalid et al, 2008;John and Anandjiwala, 2009;Bettini et al, 2010;Guo et al, 2010;Mohanty and Nayak, 2010). According to some authors, with an increasing fiber content, the energy absorbed through the pull-out mechanism will also increase (John and Anandjiwala, 2009;Bettini et al, 2010).…”

“…For jute and flax composites there was an initial slight increase in the UI strength from 20 to 35 wt% fiber content but then a decrease for 44 wt%. Guo et al (2010) analyzed the NI behavior of a large variety of injection molded NFs reinforced PP composites with MAPP as coupling agent. Results showed how difficult is to achieve uniform criteria regarding the use of coupling agents and fiber contents.…”

“…The authors reported that composites without MAPP had slightly higher average NI strength (however the difference was within the measurement error). Guo et al (2010) analyzed the effect of 2 wt% MAPP coupling agent in a large number of injection molded NF reinforced PP composites with 30 and 50 wt% fiber. The study of NFTP NI strength showed little significant effect of MAPP on the NI performance across the range of different fiber types considered.…”