The efficiency of two coupling agents in wood-polymer composites was investigated in this study. Thermal behavior of neat polypropylene, wood flour/polypropylene composite, maleated anhydride polypropylene-reinforced wood-polymer composite, and oxidized polypropylene-reinforced wood-polymer composite was investigated by means of differential scanning calorimetry and scanning electron microscopy in order to obtain information on the dispersion of the wood flour in the polymeric matrix, on the crystallization kinetics of polypropylene, and the macrostructure of its composites. The results confirm the expected nucleant effect of wood with and without the coupling agents used. The wide angle X-ray diffraction patterns indicated enhanced compatibility between polypropylene and wood with the addition of coupling agent. As a coupling agent, maleated anhydride polypropylene had a better performance in wood-polymer composites than polypropylene oxide and neat polypropylene because of its stronger interfacial bonding. Coupling agents help overcome the polarity disparity increase. All the results showed that with maleated anhydride polypropylene, oxidized polypropylene or without any coupling agent, wood flour acted as nucleating agent and increased the crystallization rate of polypropylene. For the composites, wood with maleated anhydride polypropylene was a more effective nucleating agent for polypropylene than wood with oxidized polypropylene. The mechanical properties were evaluated and the samples with coupling agent showed superior results like tensile and flexural properties.

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.

The effect of gamma radiation on the morphology, thermal behavior and mechanical properties of wood polypropylene composites has been investigated. Simultaneous thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) have been performed on wood polymer composite (WPC) samples of 9.5 ± 0.1 mg. These samples were exposed to different gamma dose in the range 10–100 kGy. The results indicated that gamma radiation improves the mechanical properties while the thermal stability is decreased. With gamma radiation, the scanning electron microscopy (SEM) of the micrographs became smoother and we can notice an improvement of interaction between polymer and wood fibers.

After a few years of calm, the investigations on the dynamic, especially nonlinear, systems returned to the front of the research in non-linear physics. We propose, in this chapter, a study of an electrical nonlinear transmission line, realized in a previous work, to use the latter to highlight certain properties (modulation instability—MI, Fermi-Pasta-Ulam (FPU) recurrence, fragmentation of solitons in wave trains, multiplication(increase) and division of frequencies, etc.), which are observed in several domains in applied physics: hydraulic, artificial neuronal, network physical appearance (physics) of the plasma, and the circulation.