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Polylactic acid (PLA) composites reinforced with 10 wt% of flax (FF) or bamboo (BF) fibers were prepared via an internal mixer and/or twin-screw extrusion. Alkali pretreated fibers were soaked in silane to improve adhesion between fibers and matrix. 0.8 wt% of Joncryl™, a grafted copolymer acting as PLA chain extender, was also used alone or in combination with silane treatment of fibers to improve interfacial adhesion. The influence of silane treatment and/or Joncryl on the composite materials on mechanical, thermal and thermomechanical properties of materials processed through injection molding was investigated. Improved adhesion of the fibers to the matrix was shown using a scanning electron microscope. Fourier Transform Infrared Spectroscopy indicated that chemical bonds were formed between the silane coupling agent and fibers. X-ray Photo-electron Spectroscopy confirmed that fibers and silane derivatives were effectively coupled. XPS also highlighted that silane coupling agent reacted in higher amounts on bamboo than flax fibers, probably due to a higher amount of lignin in the case of bamboo fibers. Thermogravimetric analyses indicated that silane-treated flax and bamboo increased the thermal stability of the corresponding composites (PLA-SFF and PLA-SFB) compared to non-treated fiber composites. The incorporation of Joncryl alone entailed a degradation of the thermal stability of the corresponding composites (PLAJ-FF and PLAJ-FB) but enhanced the PLA/fibers interfacial adhesion. The combination of Joncryl and silane treatment resulted in strong improvements of thermal stability and interfacial adhesion for the PLAJ-SFF and PLAJ-SBF composites. Increase in tensile moduli and decrease in tensile strengths with the incorporation of the pristine fibers were noted. For silane-treated fibers, the tensile modulus and the strength of the corresponding composites were improved when adding Joncryl alone or in combination with silane. From also rheological and molar weight measurements, it could be concluded that Joncryl acts both as PLA chain extender and coupling agent. [ABSTRACT FROM AUTHOR]

Extrusion and hot compressing molding processes were used to create bio-polyethylene (BioPE) composites reinforced with argan byproducts (shell, pulp, and argan cake) as bio-fillers. The thermal stability of the composites wass analyzed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Dynamical mechanical analysis and rheological testing were used to investigate their mechanical properties. The morphological results showed a good adhesion between the argan and BioPE matrix. More efficient mechanical properties have been distinguished in the case of argan byproduct-based composite. A higher Young's modulus was noted for all the biocomposites compared to pure BioPE. Thermal analysis revealed that the addition of bio-filler to polymer reduced decomposition temperatures. This study provides an ecological alternative for upgrading the valorization of abundant and underutilized Moroccan biomass. Furthermore, the possibility of using argan byproducts in composite manufacturing will help open up new markets for what is currently considered waste. [ABSTRACT FROM AUTHOR]

Fused deposition modelling is a rapidly growing additive manufacturing technology due to its ability to build functional parts with complex geometries. The mechanical properties of a built part depend on several process parameters. The effect of wood content on the properties of 3D printed parts has been studied. Four types of filaments using poly(butylene succinate-co-adipate) (PBSA) with different reinforcement levels of Typha stem powder 0%, 5%, 10%, and 15% by weight were used for 3D printing. The density of the filaments and parts printed in this study increased with the Typha stem powder content. The thermal stability, mechanical performance, and viscoelastic properties of the different biocomposite filaments and 3D printed objects were analysed. The results show an increase in the crystallisation kinetics and a slight decrease in the thermal stability of the biomaterials. Compared to virgin PBSA FDM filaments, the PBSA biocomposite filament filled with Typha stem powder showed an increase in the tensile strength of the parts and specimens from 2.5 MPa to 8 MPa and in the modulus of elasticity from 160 MPa to 375 MPa, respectively, with additions of 5%, 10%, and 15% by mass. The addition of Typha stem fibres generated an increase in the elastic behaviour and relaxation time of the biomaterial structure, visualised by increases in the values of the viscosity components. The surface morphology reveals a decrease in the porosity of the printed samples. [ABSTRACT FROM AUTHOR]

Poly(butylene succinate-co-butylene adipate) (PBSA)-based materials are receiving growing attention in the packaging industry for their promising biodegradability. However, poor gas barrier properties and low durability of biodegradable polymers, such as PBSA, have limited their wide-spread use in food packaging applications. Here we report a scalable solution to improve gas barrier properties and stabilize PBSA against photo-aging, with minimal modifications to the biodegradable polymer backbone by using a commercially available and biocompatible layered double hydroxide (LDH) filler. We investigate and compare the mechanical, gas barrier, and photoaging properties of PBSA and PBSA-LDH nanocomposite films produced on a pilot scale. An increase in rigidity in the nanocomposite was observed upon addition of LDH fillers to neat PBSA, which direct the application of neat PBSA and PBSA-LDH nanocomposite to different food packaging applications. The addition of LDH fillers into neat PBSA improves the oxygen and water vapour barriers for the PBSA based nanocomposites, which increases the attractiveness of PBSA material in food packaging applications. Through changes in the viscoelastic behaviour, we observe an improved photo-durability of photoaged PBSA-LDH nanocomposites compared to neat PBSA. It is clear from our studies that the presence of LDH enhances the lifetime durability and modulates the photodegradation rate of the elaborated biocomposites. [ABSTRACT FROM AUTHOR]

In the furniture, automotive and contruction industries, there is increased demand for cost-effective and lightweight biocomposites. The objective of this work was to develop new natural fibre-based composites with specific properties. Palm and pineapple leaf fibres were chosen in association with polypropylene (PP). The first step was to investigate the effect of these natural fibres as reinforcement for PP. The evolution of chemical structure and crystallinity was proposed with infrared spectroscopy measurements and differential scanning calorimetry thermograms, respectively. The assessments of mechanical properties with tensile tests and melt viscoelastic behaviour were also investigated. The study enabled to distinguish the influence of fibre content. The second step in our work was to assess the composite durability after ultraviolet exposure or thermal ageing. The oxidation level was calculated. The long-term evolution of thermal and mechanical properties was also proposed. As a result, the PP/pineapple leaf composite revealed a promising biocomposite. [ABSTRACT FROM AUTHOR]

Composites have been prepared with polypropylene (PP) as a matrix and pine flours, either thermally treated (Wtr) or not (W), as fillers resulting in wood plastic composites (WPCs). The treatment by retification at 280° mainly elevates the hydrophobicity of wood. The WPCs were fabricated with a co-rotating twin-screw extruder with the screw speeds of 500 and 1200 rpm and specimens were prepared by injection molding. Viscoelastic behavior, tensile test and Charpy impact test of Wtr PC were compared with PP and WPC. Wtr PC has a better dispersion and highest tensile modulus. As expected, a decrease in elongation at break and impact strength was observed for all composites. Processing at 1200 rpm improved by 60% the Young modulus of the WPC compared to 500 rpm, whereas 500 rpm was enough to obtain the highest modulus for Wtr PC. [ABSTRACT FROM AUTHOR]

An eco-friendly solution to produce new material for the material extrusion process is to use quarry waste as filler for biopolymer composites. A quarry waste that is still studied little as a filler for polymer composites is pozzolan. In this study, the optimization of the formulations and processing parameters of composites produced with pozzolan and bio-based polyethylene for 3D printing technology was performed. Furthermore, a precision irrigation system in the form of a drip watering cup was designed, printed, and characterized. The results showed that the presence of the pozzolan acted as a reinforcement for the composite material and improved the cohesion between the layers of the 3D printed objects. Furthermore, the optimization of the process conditions made it possible to print pieces of complex geometry and permeable parts for the control of the water flow rates with an order of magnitude in the range from mL/h to mL/day. [ABSTRACT FROM AUTHOR]

A new eco-composite polymer for material extrusion fabrication based on fine fraction pozzolan waste was developed. In addition, the composite materials obtained were used to produce a self-watering pot with complex geometry and a permeable porous part to regulate the passage of water from the storage area to the roots of the plant. Moreover, the system was devised with a cover characterized by a UV-B barrier film. The results have shown the possibility of the 3D printing of complex geometric parts as microporous structures or thin films using a composite based on poly lactic acid (PLA) and pozzolan. The pozzolan has an effect of reinforcement for the composite and at the same time improves the cohesion between the layers of the part during printing. [ABSTRACT FROM AUTHOR]