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This study investigates the morphology and properties of biocomposites based on a blend of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) and poly (lactic acid) (PLA) 50/50 (w/w) reinforced with untreated (UNDF) and alkali‐treated (ATDF) Diss (Ampelodesmos mauritanicus) fibers at 20 wt. %. Moreover, PHBV‐g‐MA used as the compatibilizer was added at 5 wt. % to the alkali‐treated biocomposites. Morphology, and crystallinity, thermal, thermo‐mechanical, rheological and mechanical properties of PHBV/PLA biocomposites were studied. The study showed that the treated Diss fibers were uniformly dispersed in both PLA and PHBV phases. This results in a good interfacial adhesion between the components, as observed by scanning electron microscopy (SEM). Further, the results also indicated that the compatibilized biocomposite samples showed an enhancement in crystallinity degree and heat deflection temperature (HDT) passing from 48.7% to 62.4% and 119.2 to 132.9°C, respectively, in comparison with the neat blend. Similar trend is also observed with the tensile data indicating a significant increase in Young's modulus by almost 48.5% compared to PHBV/PLA matrix. This is due to better interactions between Diss fibers and PHBV/PLA matrix. The results suggest the occurrence of a synergistic effect between PHBV‐g‐MA and alkali‐treated Diss fibers in the development of materials with interesting properties and could be a potential means to expand their applications. [ABSTRACT FROM AUTHOR]

This work aims at investigating the effect of two eco‐friendly chemical treatments of Agave Americana fibers (AAFs) on morphology and mechanical properties of poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) (PHBHHx) biocomposites prepared by melt compounding. Acid citric and sodium bicarbonate treatments are used separately to modify the fiber surface before their incorporation into PHBHHx matrix at 30 wt%. The study reveals through SEM observations that the fracture surface of untreated PHBHHx biocomposite shows a poor fiber‐matrix adhesion with the presence of many microvoids at interface and also some fibers pullout. However, less surface defects with a finer morphology are observed on the treated biocomposite samples resulting in improved tensile and flexural properties compared with neat polymer, being however, more pronounced for those modified with sodium bicarbonate. The study highlights the beneficial effect of the green treatments investigated to enhance the mechanical properties of PHBHHx biocomposites. [ABSTRACT FROM AUTHOR]

The effect of hydroxyapatite (HAp) synthesized by the chemical precipitation process on the morphology and properties of composites based on poly(lactic acid) (PLA) was investigated at various filler content ratios, i.e., 5, 10 and 15 wt%. Both neat PLA and PLA-based composites were first prepared using the solvent casting method, followed by melt compounding in an internal mixer, whereas tensile specimens were obtained by thermo-compression. The study revealed that the addition of 5 wt% of HAp into the PLA led to a slight improvement in both the thermal stability and tensile properties of the composite material in comparison with neat PLA and other composite samples. Indeed, the values of the tensile strength and modulus increased from approximately 61 MPa and 2.9 GPa for the neat PLA to almost 64 MPa and 3.057 GPa for the composite sample, respectively. Moreover, the degradation temperature at a 5 wt% mass loss also increased by almost 5 °C compared to other samples, due probably to a finer dispersion of the HAp particles in the PLA, as observed under a scanning electron microscope. Furthermore, the FT-IR spectra displayed some changes in the chemical structure of the PLA/HAp (5 wt%), indicating the occurrence of filler-matrix interactions. At a higher filler content ratio, a decrease in the properties of the PLA/HAp composites was observed, being more pronounced at 15 wt%. The PLA composite containing 5 wt% HAp presents the best compromise among the investigated properties. The study highlighted the possibility of using HAp without any prior surface treatment as a reinforcement in PLA composite materials. [ABSTRACT FROM AUTHOR]

Green biocomposites based on poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) reinforced with Agave Americana fibers (AAF) were elaborated by melt compounding at various fiber content ratios, that is, 10, 20, and 30 wt.%. Morphology before and after tensile testing, rheological, viscoelastic, mechanical, and thermal properties of the biocomposite samples were investigated with respect to the AAF content. Tensile and DMA data showed a significant increase in both Young's modulus and storage modulus of PHBHHx biocomposites with the AAF content, however, more relevant at 30 wt.%. However, a slight decrease in tensile strength and strain at break was observed, while thermal stability remained almost unchanged whatever the AAF content. The study highlighted the reinforcement effect of AAF in PHBHHx biocomposite materials, in particular at filler content of 30 wt. %. Graphical Abstract [ABSTRACT FROM AUTHOR]

The development of new bio‐based and biodegradable composites with enhanced performances is an efficient route to achieve a sustainable materials production. In this work, biocomposites materials based on PHBHHx reinforced with Agave leaves fibers (ALF) are elaborated by melt compounding at various filler content ratios, i.e., 10, 20, and 30 wt%. Thermal stability, tensile, and surface properties are investigated aiming to evaluate the effect of the ALF content on the material properties. The results show that the addition of ALF leads to reinforcement effect on PHBHHx, which is more pronounced at 30 wt%. Conversely, thermal stability of the biocomposites slightly decreases compared with the neat polymer, while the surface properties are almost unchanged whatever the filler content. [ABSTRACT FROM AUTHOR]

In this study, biocomposites of poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) (PHBHHx)/cellulose microcrystalline (MCC) extracted from olive husk flour are prepared by melt compounding at various filler content ratios, i.e., 10, 20, and 30 wt%. The effect of the MCC content on the morphology, thermal stability, crystallinity, and water uptake of the PHBHHx biocomposites is investigated. The results showed that the addition of MCC to PHBHHx decreased the thermal stability of the biocomposites compared to that of neat polymer, however more pronounced at a higher filler content. This is due probably to the tendency of MCC particles to agglomerate, inducing heterogeneities and defects within the polymer matrix observed by scanning electron microscopy. Furthermore, both crystallinity and water uptake after 24 h of immersion increased with the filler content. [ABSTRACT FROM AUTHOR]

The paper deals with the influence of surface treatment of olive husk flour (OHF) by trimethoxyoctadecylsilane (TMOS) on the morphology and physical properties of bio-composites based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). Biocomposites based on PHBV/OHF: 80/20 (w/w) before and after filler treatment were prepared by melt compounding, while the modification of OHF surface by TMOS was performed by thermo-chemical vapor deposition. Scanning electron microscopic observations showed that modification of OHF by TMOS led to homogeneous and finer dispersion of the filler particles in PHBV matrix, indicating improved compatibility between the two components. Further, TGA data revealed an increase in thermal stability of treated PHBV/OHF biocomposites. An increase in the crystalline index determined by DSC was also observed due to the nucleating effect of OHF in the polymer matrix, however more pronounced for the treated biocomposites. The latter exhibited better tensile properties, as confirmed by DMA results, showing higher reinforcing effect of OHF for the treated biocomposites. This study highlighted significant improvements of the properties of PHBV/OHF biocomposites through silane treatment of OHF. [ABSTRACT FROM AUTHOR]

Highlights The present research investigates the influence of chemical modifications on the surface of Diss fibers (Ampelodesmos mauritanicus) as an effective reinforcing agent for biocomposites based on poly (3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV). The Diss fiber surface underwent three different chemical treatments: alkaline, alkaline/peroxide, and alkaline/silane. Changes in morphology, mechanical properties, thermomechanical behavior, and contact angle measurements of the biocomposite materials were studied according to the following weight ratio PHBV/Diss fibers 80/20. Scanning electron microscopy (SEM) analysis of the fractured surface of the biocomposite samples revealed improved adhesion between Diss fibers and the PHBV matrix after surface modification, compared with the unmodified sample. The study demonstrated that the incorporation of Diss fibers leads to an enhancement in the mechanical performances of PHBV‐based biocomposites. The tensile properties of the modified biocomposites showed a significant increase in Young's modulus compared with the biocomposites with untreated fiber. Similar trends were observed in the data obtained from dynamic mechanical analysis (DMA) and contact angle measurement. Overall, the study highlights the beneficial effects of Diss fibers modification, particularly with the alkali–silane combination, in enhancing the properties of PHBV biocomposites, there by broadening their potential application fields. The study explores the potential of Diss fibers as an effective reinforcement for PHBV‐based biocomposites. Fully biodegradable biocomposites based on PHBV/Diss fibers are melt‐compounded. Diss fibers are chemically modified by alkaline, alkaline/peroxide, and alkaline/silane. The chemical treatment has considerably enhanced the properties and morphology of the biocomposites, being however much higher for alkaline/silane treatment. The method can be used for specific applications and large‐scale production. [ABSTRACT FROM AUTHOR]

In recent years, there has been a great interest in biodegradable polymer composites. Besides polylactides, polyhydroxyalcanoates (PHA) are the most commonly used as matrices due to their biodegradability, biocompatibility and good properties compared with synthetic polymers. Despite many advantages, bio-fillers still have limited applications as reinforcement due to a lack of adhesion to polymers and their inherent high moisture absorption. Therefore, achieving a good adhesion between bio-fillers and the polymer represents one of the major challenges in composite materials. Therefore, the objective of this paper was to investigate the effect of PHBV grafted maleic anhydride (PHBV-g-MA) compatibilizer used at 5 wt. %, on the morphology and properties of PHBV/OHF biocomposites at various filler contents, i.e., 10, 20 and 30 wt.%. The study showed that PHBV-g-MA improved filler dispersion in the matrix and promoted the interactions between PHBV and OHF resulting in improved thermal stability and tensile and barrier properties compared to the non-compatibilized biocomposites. [ABSTRACT FROM AUTHOR]

The paper reports some experimental results on the effect of different chemical modifications of Diss fibers on the properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) biocomposites involving alkaline, combined alkaline/peroxide and combined alkaline/silane treatments. The biocomposite samples loaded at 20 wt% were prepared by melt compounding. Scanning Electron Microscopy (SEM) showed a better fiber-matrix interaction between Diss fiber and matrix after surface fiber treatment. Differential Scanning Calorimetry (DSC) and X-ray Diffraction (XRD) results indicated an increase in crystallinity index of the biocomposites. In addition, the incorporation of Diss fibers treated with alkali-silane resulted in an improvement in Heat Deflection Temperature (HDT) and shore D hardness from 141.1 °C and 75.1–145.7°C and 86.2, respectively, in comparison with the neat matrix. This also agreed with the flexural properties results, which showed a significant increase in flexural modulus by almost 30 % compared to the neat PHBV. The same trend was observed for water absorption. Overall, combined alkali-silane treatment was found to be most efficient surface treatment method to develop strong interfacial adhesion between PHBV and Diss fiber, increasing the scope of application in manufacturing of light weight green composites. • Effect of various surface treatments on Diss fibers used as reinforcement in PHBV-based biocomposites. • Structural and properties characterization of Diss fibers and PHBV/Diss fibers biocomposite 80/20 (w/w). • Interesting Diss source of cellulosic reinforcing materials. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the effect of various surface treatments on Aloe Vera fibers (AVF) used as reinforcement in PHBHHx biocomposites prepared by melt compounding. AVF were subjected to various surface treatments including alkaline, organo-silanes and combined alkaline/organo-silanes treatments. Both untreated and treated AVF were added to PHBHHx at filler content of 20 wt% and the resulted biocomposites were characterized using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), water absorption test and rheological measurements. The study showed that the combined alkaline/organo-silanes treatment of AVF resulted in better morphology and properties of PHBHHx biocomposite compared to untreated AVF and those treated either with alkaline or with organosilanes. Indeed, SEM analysis of the fracture surface of PHBHHx/AVF treated with combined alkaline-organosilanes showed better fiber-matrix interactions compared to the other samples. As a result, rheological properties, i.e., complex viscosity (η∗), storage modulus (G′) and loss modulus (G″) were increased. Higher resistance to water absorption was observed for PHBHHx/AVF treated with combined alkaline-organosilanes. Whereas, the various surface fiber treatments led to no noticeable change in thermal characteristics of the biocomposites. This study highlights the effectiveness of combined alkaline/organo-silanes treatment of AVF over alkaline and organo-silanes and their applications in PHBHHx biocomposites as an interesting source of cellulosic reinforcing materials. • Effect of surface treatments on Aloe Vera fibers (AVF) used as reinforcement in PHBHHx biocomposites. • Morphological and properties characterization of AVF and PHBHHx/AVF: 80/20 (w/w) biocomposite before and after treatments. • Improvement in fiber-matrix interface achieved by the combined alkaline-organosilanes treatment of AVF. • Interesting AVF source of cellulosic reinforcement materials. [ABSTRACT FROM AUTHOR]