In this paper, 400 flax fibers with 10 different lengths (40 fibers at each length) are experimentally characterized (quasi-static tensile behavior) and then the results are statistically analyzed. The quasi-static tensile test results appeared to have a large dispersion, which makes it possible to measure the degree of variability in the ultimate tensile strength (UTS), failure strain, and the Young’s modulus of the fiber, at different gage lengths (10 mm to 500 mm). The variation in mechanical properties at each fiber length is established using two and three Weibull statistics based on maximum likelihood estimation (ML) and least square estimation (LS). Finally, all 10 groups for each tensile property are analyzed by one-way (ANOVA).

In this research work, we aim to study the effect of the incorporation of vegetable fiber reinforcement on the thermo-mechanical and dynamic properties of a composite formed by a polymeric matrix reinforced with cellulosic fibers with the various Washingtonia fiber (WF) loadings (0%, 10%, 20%, and 30% by wt%) as reinforced material in high-density polyethylene (HDPE) Biocomposites to evaluate the optimum fiber loading of biocomposites. In addition, several characterization techniques (i.e., thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermal mechanical analysis (TMA)) were used to better understand the characteristics of the new composites prepared. With these techniques, we managed to verify the rigidity and thermal stability of the composites so elaborated, as well as the success of the polymer and the structural homogeneity of the obtained biocomposites. Hence, the biocomposite with the best ratio (HDPE/20WF) showed a loss modulus (E″) of 224 MPa, a storage modulus (E′) of 2079 MPa, and a damping factor (Tanδ) of 0.270 to the glass transition (Tg) of 145 °C. In addition, thermomechanical analysis (TMA) of the biocomposite samples exhibited marginally higher Ts compared to the HDPE matrix. The best results were recorded with biocomposites with 20% WF, which showed better thermal properties. This composite material can be used as insulation in construction materials (buildings, false ceilings, walls, etc.).

In this study, biocomposites of HDPE/flax fibers in different formulations were developed and their tensile, 3-point bending, and morphological properties were extensively characterized. The interfacial bond in the fractured biocomposite samples was examined by scanning electron microscopy (SEM). While the thermal behavior of these novel HDPE/flax biocomposites was studied using DSC and ATG. The ratio of tested reinforcement by weight varies from 5% to 20% of natural flax fiber with different heating rates, namely 5°C/min, 10°C/min, and 20°C/min. The results for the mechanical properties obtained such as the tensile and flexural strength revealed an increase of 24 to 35 MPa and 15.82 to 19.72 MPa, respectively, compared to neat HDPE. On the other hand, the thermal tests revealed that the heating rate has a pronounced effect on the thermal behavior of the materials studied by shifting the degradation range of biocomposites to high temperatures.

Micronic and submicronic mineral fillers recently appeared as efficient reinforcing agents for polyolefins in addition to the benefit of bypassing the exfoliation/dispersion problem encountered in the case of incorporation of nanoscopic fillers such as clay. Submicronic-talc, designated as μ-talc, belongs to this kind of new fillers. This work was aimed at searching to optimize the crystallinity ratio of isotactic polypropylene in the presence of μ-talc in relation to the filler ratio of the composites and the cooling rate from the melt. In order to highlight the efficiency of the μ-talc on the crystallization of polypropylene comparison has been made with PP composites containing conventional talc particles. The study has been carried out on samples having μ-talc weight fractions covering the range 3–30%. In the context of optimizing the crystallinity ratio of the polypropylene matrix in the composites, calorimetric experiments have been planned using a full factorial design. The results were statistically processed by analysis of the variance via mathematical models for predicting the crystallinity ratio in relation to the cooling rate and the filler ratio. Contour graphs have been plotted to determine the effect of each parameter on crystallinity. The cooling rate proved to have a significantly stronger influence on crystallinity than the type and content of filler

In this study, biocomposites fibers (flax/epoxy) with different fiber ratios were manufactured and their tensile, 3-point bending and morphological properties were characterized. The interfacial binding of fractured composite samples after tensile and 3-point bending tests were examined by scanning electron microscopy (SEM). The mechanical results revealed an increase in the composite sample manufactured by second formulation CT090 (biocomposites UD [0/90°]_s treated by NaHCO₃) compared to the different formulations studied. For example, the stress and Young’s modulus values of qua-static traction of the biocomposite CT090 treated with sodium bicarbonate are obtained to be 70.13 MPa and 1420.47 MPa, respectively. The overall test results stated that bio sodium carbonate treatment enhanced the mechanical and morphological properties of the biocomposites in this study. Finally, the experimental results were subjected to a one-way analysis of variance (ANOVA) using MINITAB software.