Flax/PP manufacture by automated fibre placement (AFP)

Abstract

Automated fibre placement (AFP) has been used to manufacture flax/polypropylene biocomposites for the first time. This required preparation of tape with a calibrated width from impregnated fibre sheets. The unidirectional tapes showed polymer-rich zones on the surface. During manufacture the polypropylene (PP) is melted locally with a laser. A consolidation step in a hot press is then required to reduce void content. The flax fibres, composed of polysaccharides, have limited thermal resistance so optimization of the thermal cycle is necessary, but subsequent characterization of mechanical behaviour showed no evidence of property loss in spite of an additional melting cycle. AFP appears to be a promising manufacturing method for biocomposites. Graphical abstract Highlights ► A new process to produce flax/PP tape for AFP is described, using calendering between rollers. ► Microstructure analysis shows surface polymer and good impregnation. ► AFP forming process allows manufacture of temperature sensitive natural fibres. ► Mechanical properties comparable to those for compression moulded plate specimens.

Variability of mechanical properties of flax fibres for composite reinforcement. A review

“…As noted above the curve is non-linear (Andersons et al, 2015). Similar behaviour has been noted for composites with thermoset (Baets et al, 2014) (Coroller et al, 2013) and thermoplastic matrix polymers, such as PP (Baley et al, 2016) and PA11 . The behaviour is generally considered in two strain ranges and thus low strain and high strain tangent modulus values can be determined (Bensadoun et al, 2015) (Shah, 2016) (Bensadoun et al, 2017).…”

Lay-Up and Consolidation of a Composite Pipe by In Situ Ultrasonic Welding of a Thermoplastic Matrix Composite Tape

“…The interest in continuous fiber-reinforced thermoplastic composites is continuously increasing due to their inherent benefits compared with thermoset composites such as damage tolerance, high impact resistance, chemical and solvent resistance, unlimited shelf life, low storage costs, weldability, and recyclability [ 1 , 2 , 3 ]. Other key advantages of thermoplastic composites include the potential of fast in situ out-of-autoclave processing, by applying pressure and heat in one step, and the potential for automation with significant decrease of work time and costs [ 4 , 5 ]. For these reasons, fiber-reinforced thermoplastic composites are continuously replacing traditional materials like metals and wood in many applications [ 6 , 7 ].…”

Defect Characteristics and Online Detection Techniques During Manufacturing of FRPs Using Automated Fiber Placement: A Review

“…Depending on the shape of the mold surface, the AFP process can use multiple prepreg tows (8~32 tows) to realize continuous variable angle placement. Additionally, it can cut/refeed the tow to adapt to the change of the manufacturing boundary, which can guarantee the processing requirements of complex structures [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. The AFP working principle [ 22 ] and AFP machine produced by Harbin Institute of Technology (HIT) are shown in Figure 1 .…”

“…Polymers 2020, 12, x FOR PEER REVIEW 2 of 22 complex structures [16][17][18][19][20][21][22][23]. The AFP working principle [22] and AFP machine produced by Harbin Institute of Technology (HIT) are shown in Figure 1.…”