Search

This paper aims to investigate the optimal formulation of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx)/ZnO bionanocomposites for food packaging applications with respect to filler content ratio. Bionanocomposite samples prepared by melt-compounding at various ZnO-NPs contents (1.5, 3, and 6 wt%) were evaluated in terms of optical, thermal, viscoelastic, and mechanical properties. UV–Vis spectroscopy revealed a significant enhancement in the photochemical stability of PHBHHx/ZnO bionanocomposites compared with neat PHBHHx, which exhibits a strong absorption band at wavelengths below 380 nm, thus confirming the anti-UV activity of ZnO nanoparticles. Thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA) demonstrated improved thermal stability and increased stiffness/mechanical strength with increasing ZnO-NPs content. Notably, the bionanocomposite with 3 wt% of ZnO exhibited the most substantial improvements, with a 20% increase in thermal decomposition temperature and a 30% increase in storage's modulus at room temperature than the neat PHBHHx. Moreover, a decrease in loss modulus (E″) and tanδ indicated reduced energy dissipation and enhanced material elasticity. Overall, incorporating 3 wt% ZnO nanoparticles into PHBHHx resulted in a bionanocomposite with superior photochemical stability, thermal stability, and viscoelastic properties compared to both neat PHBHHx and other bionanocomposite samples, which makes it as a promising candidate for food packaging 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]

Chemical treatments are used to remove hydrophilic OH groups and surface particles from the fiber surface for increasing aspect ratio of fibers and subsequently, mechanical properties. In this paper, the effect of two eco‐friendly chemical treatments on morphology, chemical structure, and thermal stability of Agave Americana fibers (AAFs) is investigated. The first chemical treatment of AAF is based on citric acid (C6H8O7) to substitute OH groups contained in AAF by ester groups, while the second one involves sodium bicarbonate (NaHCO3) to remove the lignin and hemicellulose components with the aim to promote good fiber‐matrix adhesion. Attenuated total reflectance‐Fourier transform infrared spectroscopy (ATR‐FTIR) data shows that both treatments are efficient to remove hemicelluloses and a part of lignin contained in AAF resulting in a rough and clean fiber surface. Thermal stability of AAF has clearly increased by NaHCO3 treatment compared to untreated one, unlike C6H8O7, which reduces this property. The study highlights the possibility of substituting conventional polluting chemical treatments with environmentally friendly ones to modify the surface of plant fibers for polymer composites reinforcement. [ABSTRACT FROM AUTHOR]

Given the global challenge of plastic pollution, the development of new bioplastics to replace conventional polymers has become a priority. It is therefore essential to achieve a balance in the performances of biopolymers in order to improve their commercial availability. In this topic, this study aims to investigate the morphology and properties of poly(lactic acid) (PLA)/ poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) (at a ratio of 75/25 (w/w)) blends reinforced with halloysite nanotubes (HNTs) and compatibilized with poly(lactic acid)-grafted maleic anhydride (PLA-g-MA). HNTs and PLA-g-MA were added to the polymer blend at 5 and 10 wt.%, respectively, and everything was processed via melt compounding. A scanning electron microscopy (SEM) analysis shows that HNTs are preferentially localized in PHBHHx nodules rather than in the PLA matrix due to its higher wettability. When HNTs are combined with PLA-g-MA, a finer and a more homogeneous morphology is observed, resulting in a reduction in the size of PHBHHx nodules. The presence of HNTs in the polymer blend improves the impact strength from 12.7 to 20.9 kJ/mm2. Further, with the addition of PLA-g-MA to PLA/PHBHHX/HNT nanocomposites, the tensile strength, elongation at break, and impact strength all improve significantly, rising from roughly 42 MPa, 14.5%, and 20.9 kJ/mm2 to nearly 46 MPa, 18.2%, and 31.2 kJ/mm2, respectively. This is consistent with the data obtained via dynamic mechanical analysis (DMA). The thermal stability of the compatibilized blend reinforced with HNTs is also improved compared to the non-compatibilized one. Overall, this study highlights the effectiveness of combining HNTs and PLA-g-AM for the properties enhancement of PLA/PHBHHx blends. [ABSTRACT FROM AUTHOR]

The effect of gamma irradiation on neat Polyamide-11 (PA11) and PA11 filled with 3 wt% of halloysite nanotubes (HNTs) was investigated at various doses up to 100 kGy in air and at room temperature. The irradiation test was conducted on sample films prepared by a twin-screw extruder in the first step then cast extrusion. The study showed the formation of a maximum of gel fraction up to 10 and 20 kGy for neat PA11 and PA11/HNTs, respectively. Furthermore, the results indicated the occurrence of crosslinking at low irradiation dose, whereas chain scission took place at higher ones. Additionally, the results revealed that the presence of HNTs limits the impacts of gamma irradiation through a barrier effect. An optimum irradiation dose was found for thermal and mechanical properties, corresponding to the dose for maximum gel formation. Moreover, experimental design was implemented to highlight the main incidences and interactions of both halloysite incorporation and radiation dose on some relevant effects of gamma irradiation. [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]

In this work, the main objective is to investigate the effect of olive husk flour (OHF) used as a biofiller on the marine degradation of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) biocomposites up to 6 months of immersion in sea water at 25°C and 40°C. Film samples based on neat PHBV and PHBV are filled with 20 wt.% OHF is prepared by melt compounding. After 6 months of immersion in sea water, the study reveals a noticeable decrease in the absorption band intensity of ester groups of PHBV through Fourier transform infrared (FTIR‐ATR) spectroscopy, even more in the presence of OHF in PHBV biocomposite due to hydrolytic degradation. This phenomenon is, however, more pronounced at 40°C. This also agrees with differential scanning calorimetry (DSC) data, which indicates a large increase in crystallinity index (Xc) resulting from short chains reorganization. Moreover, scanning electron microscopic (SEM) analysis shows for both degraded samples, eroded and cracked surfaces, being however more pronounced for PHBV/OHF biocomposite at 40°C. This study highlights the role of OHF as a promotor of marine degradation of PHBV. [ABSTRACT FROM AUTHOR]

The effect of various clays nanofillers on the photo‐oxidation of polyamide 11 (PA11) has been investigated by accelerated ultraviolet (UV) test up to 780 h. Organo‐modified montmorillonite, halloysite nanotubes, and sepiolite were selected and incorporated separately to PA11 at 5 wt.%. The samples were prepared by melt compounding. Fourier transform infrared (FTIR) data showed a linear increase of carbonyl index (CI) in the first 360 h of exposure indicating a rapid oxidation of all samples without any induction period. Further, the nanocomposite samples exhibit faster oxidation kinetics than PA11, being however less pronounced for PA11/sepiolite. This is consistent with both the yellowing index (YI) evolution determined by UV–Vis spectroscopy and also the onset oxidation temperature (OOT) determined by differential scanning calorimetry (DSC). [ABSTRACT FROM AUTHOR]

The objective of the paper is to investigate the effect of organo‐modified sepiolite (MSep) on morphology, mechanical, and viscoelastic properties of polyamide‐11 (PA11) prepared by melt compounding at 5 wt.%. The study reveals that the addition of both unmodified sepiolite (USep) and organo‐MSep to PA11 improves the reinforcement effect of the nanocomposite materials compared to neat PA11, being however more pronounced for the organo‐modified one. Indeed, morphological analysis by transmission electron microscopy (TEM) shows a finer dispersion of organo‐MSep in PA11 matrix than the unmodified one, which is characterized by a significant presence of fibers aggregates in number and size. Further, dynamic mechanical analysis (DMA) results are in a good agreement with both tensile properties and TEM observations. [ABSTRACT FROM AUTHOR]

Hygrothermal aging of neat poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) and PHBV filled with an organomodified montmorillonite (C30B) at 3wt. was investigated at 65°C and 100% relative humidity (RH) up to 100 days. FT‐IR data indicated that the carbonyl intensity index decreased with exposure time for both samples, while the main degradation mechanism occurred through hydrolysis reaction. This led to chain scissions resulting in a decrease in molar mass. Water absorption increased with exposure time for both neat PHBV and PHBV/C30B (3wt%) bionanocomposite. Differential scanning calorimetry measurements showed a decrease in both crystallinity index and melting temperature after hygrothermal aging and thermogravimetric analysis data indicated also a decrease in thermal stability. Mechanical and viscoelastic properties were also altered, being, however, more pronounced for the neat PHBV. Overall, the PHBV bionanocomposite exhibited a better resistance toward hygrothermal aging at 65°C and 100% RH. [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 aim of the work was to investigate the combined effect of Sepiolite and Cloisite 30B on the morphology and properties of PHBV/PLA 50/50 w/w blend. Scanning electron microscopic analysis showed that the morphology of PHBV/PLA blend was relatively regular and homogeneous in the presence of Cloisite 30B and Sepiolite compared to the virgin blend, indicating a better compatibility between the two base polymers. The thermal stability of PHBV/PLA blend was enhanced by the clay fillers. Modulus and hardness were also increased in comparison with the virgin blend. The rheological measurements showed a significant increase in both the complex viscosity and storage modulus of the filled blend due to interactions between the clays fillers and the PHBV/PLA blend. [ABSTRACT FROM AUTHOR]

Abstract: In this study, multifilament fibers based on neat poly(lactic acid) (PLA), PLA/cellulose nanowhiskers (CNWs), and PLA/cellulose microcrystalline (MCC) loaded at 1 and 3 wt.% were prepared by melt‐spinning process in the presence of PLA‐grafted maleic anhydride (PLA‐g‐MA) used as the compatibilizer and PEG as the plasticizer. This study showed that the incorporation of MCC in PLA matrix whatever the loading rate was not suitable for multifilament fibers spinning compared with CNW, due to the restricted drawability and a poor dispersion of the MCC within the PLA matrix. Furthermore, the whole characterization studies indicated that the incorporation of 1 wt.% of CNW in PLA with addition of the compatibilizer led to better thermal stability, flame retardancy, and multifilament tensile properties compared with neat PLA and with other filled PLA multifilament fibers. [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]

The paper provides some experimental data on the effects of a poly(3-hydroxybutyrate-co-3-hydroxyvalerate) grafted maleic anhydride (PHBV-g-MA) used as the compatibilizer for poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/olive husk flour (OHF) composites prepared by melt compounding. The natural filler was added to PHBV at various contents, i.e. 10, 20, and 30 wt%, while the amount of PHBV-g-MA was 5 wt% based on neat PHBV. Morphology, contact angle measurements, water absorption (WA), mechanical, viscoelastic, and barrier properties of the various composites were investigated with and without the compatibilizer. The study showed through scanning electron microscopy that the addition of PHBV-g-MA to PHBV/OHF composites resulted in better and finer dispersion of the filler in the matrix, even at a higher content ratio, indicating improved affinity between the components. This is in agreement with the decrease in both surface energy and WA. Furthermore, tensile and dynamic mechanical measurements indicated a reinforcing effect of OHF in PHBV composites, being more pronounced in the presence of PHBV-g-MA. The barrier properties against oxygen and water vapor were also improved for the compatibilized composites. [ABSTRACT FROM AUTHOR]

The present article reports a study of oxidative degradation under eBeam irradiation of neat PHBV, neat PLA and PHBV/PLA blend (50/50 w/w) with and without Cloisite 30B (C30B) (3 wt%) at absorbed doses of 1 and 10 kGy. The changes in the chemical structure, the molecular weight, the thermal, mechanical and barrier properties as well as the morphology were evaluated. The data showed that eBeam irradiation of PHBV/PLA blend leads to oxidation reactions involving ester groups in both neat PLA and neat PHBV resulting in the formation of hydroperoxides groups. The presence of C30B in the polymer blend has no influence on the nature of the degradation process. However, the good dispersion of C30B nanoparticles provides more stability to the molar mass and the thermal, mechanical and barrier properties of PHBV/PLA blend. At absorbed dose of 10 kGy, the irradiated samples are completely safe. Furthermore, ecotoxicity testing of both non irradiated and irradiated samples clearly showed no toxicity. [ABSTRACT FROM AUTHOR]

The paper reports some experimental data on the effects of mixing rate on the morphology, carbonyl index (I CO ), rheological and viscoelastic properties of nanocomposite materials based on bitumen/organo-modified montmorillonite (OMMT) incorporated at 3 wt.%. The melt compounding process was carried out at 140 °C under various mixing rates, i.e. 750, 1500, 2000, 3000 and 4500 rpm. The results indicated through Wide angle X-ray scattering (WAXS) that up to 2000 rpm, bitumen/OMMT nanocomposites exhibited an intercalated structure whereas at 3000 rpm and more, an exfoliated structure was observed. Atomic force microscopy (AFM) showed an homogeneous dispersion of OMMT in the bituminous matrix accompanied with a decrease in the “bee like” structure, being however more pronounced at higher mixing rate. Differential scanning calorimetry (DSC) data indicated a decrease in the crystalline index (X c ) for both neat bitumen and bitumen nanocomposites with increasing the mixing rate. Complex viscosity (η ∗ ) and complex modulus (G ∗ ) were significantly improved compared to those of neat bitumen. Fourier transform infrared spectroscopy (FTIR) analysis showed a slight increase in the I CO value of bitumen/OMMT nanocomposites, especially at 4500 rpm compared to that of neat bitumen, which remained almost constant. [ABSTRACT FROM AUTHOR]

The effects of gamma irradiation on the morphology and physical properties of various blends based on poly(3-hydroxybutyrate- co -3-hydroxyvalerate) (PHBV) and polylactide (PLA): 50/50 w/w were studied with and without PHBV- g -MA and organomodified montmorillonite used as the compatibilizer and reinforcement agent, respectively. The different blend compositions prepared by melt compounding were compression molded to thin films of an average thickness of 150 μm, and subjected to 25, 50 and 100 kGy at room temperature; the dose rate being 1.0 Gy/h. Infrared spectra analysis indicated the occurrence of some chemical modifications in the irradiated samples, in particular an absorbed dose of 100 kGy resulted in the formation of a large absorption band in the carbonyl region. Size exclusion chromatography (SEC) data showed a decrease in the average molecular weight for all irradiated samples with increasing absorbed dose due to chain scission. Nanoindentation tests showed that γ-irradiation significantly decreased both modulus and hardness of neat PHBV and neat PLA after 100 kGy, whereas no noticeable changes were observed for PHBV/PLA blends. Thermogravimetric analysis (TGA) and pyrolysis combustion flow calorimetry (PCFC) tests revealed that the organomodified clay can act as a compatibilizer and compensate for the effect of irradiation on both thermal stability and fire retardancy of PHBV/PLA blends. [ABSTRACT FROM AUTHOR]

The hydrothermal degradation at 90°C in distilled water of metallocene linear low density polyethylene films (mLLDPE) has been studied using low density polyethylene (LDPE) for comparison. FTIR spectroscopy, DSC and chemiluminescence techniques were used for investigation of the hydrothermal ageing-induced changes. The stabilization effect of a commercially available HALS, namely Sanduvor PR 31, able to graft on polyolefin structures has been also studied, as well. It was found that intense oxidation process occurs in the case of LDPE: hydroxyl, carbonyl and unsaturated groups were identified in FTIR spectra. mLLDPE reference films presented considerably higher stability as compared to LDPE ones, this behaviour being assigned to the structural peculiarities. Sanduvor PR 31 induced higher stability in LDPE, possibly by grafting mechanism, but it did not present a significant effect in the case of mLLDPE. Besides a possible antagonist interaction with the process stabilizer or a graft-hindering effect of the alkyl side groups, the intrinsic higher stability of the mLLDPE which offers less active sites for grafting could be supposed to explain this lower effectiveness. [ABSTRACT FROM AUTHOR]

Abstract: The paper aims to study blend properties of biodegradable polymers of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and polylactide (PLA) prepared by melt mixing. Blend compositions based on PHBV/PLA were investigated according to the following weight ratios, i.e. 100/0, 75/25, 50/50, 25/75 and 0/100 wt%. The study showed through scanning electron microscopy (SEM) that blends of PHBV/PLA are not miscible. This is consistent with differential scanning calorimetry (DSC) data which indicate the presence of two distinct glass transition temperatures (Tg) and melting temperatures (Tm), attributed to the neat polymers, over all the range of blend compositions. Water and oxygen barrier properties of PHBV/PLA blends are significantly improved with increasing the PHBV content in the blend. Further, morphological analyzes indicated that increasing the PHBV content in the polymer blends results in increasing the PLA crystallinity due to the finely dispersed PHBV crystals acting as a filler and a nucleating agent for PLA. On the other hand, the addition of PLA to the blend results in a very impressive increase in the complex viscosity of PHBV. Moreover, the rheological data showed that, excluding the specific behavior of the neat polymers at low frequencies, i.e. less than 0.1 Hz, the complex viscosity of PHBV/PLA blends fits the mixing law well. [Copyright &y& Elsevier]

PS/organo-modified clay (5% w/w) nanocomposite has been subjected to a series of eight processing cycles in a twin screw extruder. The influence of multiple recycling on the properties of the nanocomposite was studied by following the changes in the morphology, the molecular structure, the melt flow index (MFI) and the thermal properties. The WAXS results indicate a strong intercalation of PS chains between silicate layers of the organoclay and the extent of intercalation appears to increase with increasing the number of cycles. The main effects of recycling are a reduction in molecular weight due to chain scission, although the occurrence of a crosslinking fraction is probable after 8 cycles. The thermal properties remain almost stable during reprocessing. [ABSTRACT FROM PUBLISHER]

Abstract: This paper presents some experimental results on property changes due to thermo-oxidative aging of bitumen modified by styrene–butadiene–styrene (SBS) and ethylene vinyl acetate (EVA) copolymer incorporated at various concentrations, i.e. 3, 5 and 7wt.%. The chemical compositions, the properties and the morphology of the samples have been determined and characterized using SARA (saturates, aromatics, resins and asphaltenes) analysis, conventional test methods and optical microscopy, respectively. The study reveals that polymer modification globally improves the conventional properties of the base bitumen as evidenced by a decrease in penetrability, an increase in softening point and a reduction in temperature susceptibility inducing a rubbery elastic behavior to the base bitumen. This effect is dependent on both the type and the content of polymer used. Moreover, samples prepared with SBS show better improvement as compared with EVA modified bitumens. The morphological analysis shows that there is a clear difference between the SBS and EVA modified bitumens. For 3wt.% SBS modified bitumens, the polymer phase is homogenously dispersed in a continuous bituminous matrix consisting of polymer particles swollen by the solvating phase of the bitumen. In the case of EVA modified bitumen with the same polymer content, much finer dispersion of EVA particles is observed. After thermo-oxidative aging, the results clearly indicate a hardening of samples, being more pronounced for the base bitumen and those modified with EVA. For all samples, aging reduces the content of aromatics and at the same time increases the contents of resins and asphaltenes, while changes in the content of saturates are almost negligible. These structural modifications may result from oxidation of the bitumen and some chemical interactions with the polymers. [Copyright &y& Elsevier]

Abstract: This work focuses on the effect of repeated processing cycles on the structure and properties of PS/Cloisite 15A (5% w/w) nanocomposite through a series of eight extrusion cycles using a co-rotating intermeshing twin screw extruder. For comparison, neat PS was also reprocessed as a reference material. Changes in the nanostructure were studied by wide angle X-ray scattering (WAXS) and rheological measurements. Molecular weight change was determined by size exclusion chromatography (SEC). Chemical changes were studied by Fourier transform infrared spectroscopy (FT-IR). Furthermore, the mechanical properties were investigated by a nanoindentation test method, whereas colorimeter techniques were used to analyze yellowness during reprocessing. The results of the WAXS analysis show that the d001 peak of the PS nanocomposite shifts to lower angles with increasing the number of reprocessing cycles indicating intercalated-delaminated structure. The rheological data reveal an enhancement of G′ in the melted state with reduction of the terminal slope of the nanocomposite samples over the PS matrix, thus confirming the occurrence of strong interaction between the silicate sheets and the polymer and their tendency to form a three dimensional superstructure. Further, in contrast to neat PS which undergoes a large reduction of molecular weight with increasing the number of cycles due to chain scission; in PS nanocomposites, the SEC data shows however that the degradation involves two mechanisms: chain scission as the most prevalent one, with the probability of occurrence of some crosslinking after 8 reprocessing cycles as demonstrated by the increase in both and . Repeated reprocessing globally yield colour changes in both the neat PS and PS nanocomposites whereas, the chemical structure and nanomechanical properties remain stable during reprocessing for PS nanocomposite. [Copyright &y& Elsevier]

The paper reports some results of an experimental study on ethylene vinyl acetate (EVA) copolymer/olive husk flour (OHF) composites incorporated at various filler ratios (15, 30 and 45 wt%) in the absence and the presence of ethylene-butyl acrylate-glycidyl methacrylate (EBAGMA) terpolymer used as a compatibilizer. The composite samples have been prepared by melt blending and their chemical structure, as well as morphological, mechanical and water absorption properties investigated. It is shown that the compatibility of EVA/OHF composites is improved by the addition of EBAGMA terpolymer. Indeed, FT-IR analysis shows that chemical interactions have occurred between the compatibilizer and the base blend components. Morphological results from SEM shows better dispersion of the wood particles in the EVA matrix and the resulting composite samples exhibit better tensile properties at break and lower water absorption than the uncompatibilized ones. Moreover, the results indicate that the loading concentrations of both OHF and EBAGMA have an effect on the composite properties. [ABSTRACT FROM AUTHOR]

Abstract: The effects of reprocessing cycles on the structure and properties of isotactic polypropylene (PP)/Cloisite 15A (OMMT) (5 wt. %) nanocomposites was studied in presence of maleic anhydride-grafted-polypropylene (PP-g-MA) (20 wt. %) used as the compatibiliser to improve the clay dispersion in the polymer matrix. The various nanocomposite samples were prepared by direct melt intercalation in an internal mixer, and further they were subjected to 4 reprocessing cycles. For comparative purposes, the neat PP was also processed under the same conditions. The nanocomposite structure and the clay dispersion have been characterized by wide angle X-ray scattering (WAXS), transmission electron microscopy (TEM) and rheological measurements. Other characterization techniques such as Fourier transform infrared spectroscopy (FT-IR), tensile measurements, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) have also been used to evaluate the property changes induced by reprocessing. The study showed through XRD patterns that the repetitive reprocessing cycles modified the initial morphology of PP/OMMT nanocomposites by improving the formation of intercalated structure, especially after the fourth cycle. Further, the addition of PP-g-MA promoted the development of intercalated/exfoliated silicate layers in the PP matrix after the second cycle. These results are in agreement with TEM observations indicating an improved silicate dispersion in the polymer matrix with reprocessing cycles displaying a morphology with both intercalated/exfoliated structures. The initial storage modulus (G′) of the nanocomposites, which was highly improved in presence of PP-g-MA seems to be less affected by reprocessing cycles at very low frequencies exhibiting a quasi-plateau compared to pristine PP/OMMT and PP. In contrast, the complex viscosity was found to decrease for the whole samples indicating that the main effect of reprocessing was a decrease in the molecular weight. Moreover, the thermal and mechanical properties of the nanocomposites were significantly reduced after the first cycle; nevertheless they remained almost unchanged during recycling. No change in the chemical structure was observed in the FT-IR spectra for both the nanocomposites and neat PP samples after 4 cycles. [Copyright &y& Elsevier]

Abstract: The degradation of polylactide (PLA)/Cloisite 30B nanocomposites under natural weathering was investigated as a function of clay loadings (1, 3 and 5wt.%) for up to 130 days using Fourier transform infrared (FT-IR) spectroscopy, size exclusion chromatography (SEC), nanoindentation measurements, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). For comparative purposes, the neat PLA was also considered. The FT-IR results showed that the photo-oxidation mechanism of PLA was not modified in the presence of Cloisite 30B, but only the degradation rates were accelerated. Moreover, the photo-oxidative degradation of PLA nanocomposite samples led to the formation of vinyl unsaturation, carbonyls, anhydrides and hydroperoxides groups as a result of the occurrence of several chemical mechanisms simultaneously. The decrease of the weight-average molecular weight, and the number-average molecular weight associated with an enhanced polydispersity of the nanocomposite samples indicated that chain scission was the most prominent phenomenon in natural weathering. The thermal degradation of the PLA was faster in the presence of clay. Modulus and hardness measured by nanoindentation increased slightly with exposure time for both neat PLA and PLA nanocomposite samples; the increase is also a function of the clay content. Finally, the weathering effect on the morphology of exposed samples observed by SEM revealed that the fractured surfaces exhibited many voids and cracks. These defects were much more pronounced for the PLA nanocomposites. [ABSTRACT FROM AUTHOR]

Photostability of low-density polyethylene (LDPE) films under natural weathering conditions was investigated in the absence and the presence of various structures of hindered amine light stabilizers (HALS) by chemiluminescence (CL) and Fourier transform infrared (FTIR) spectroscopy. The stabilizers studied were Sanduvor PR 31 (as grafted HALS) and Uvasil 299 and Tinuvin 123 (as non-grafted HALS). The HALS were added separately to LDPE at the same concentration, namely 0.3% (w/w). It was found that the weathered stabilized samples exhibited a relative long period during which the CL signal slowly increased, while for unstabilized samples, CL increased after a short induction period. This behavior could be explained by reduction in the rate of hydroperoxide decomposition caused by nitroxyl radicals. However, the very high increase in stability observed in the case of Sanduvor PR 31 sample could be assigned to the grafting effect of the HALS on the polymer chain. At longer exposure times, the oxidation induction time decreased slowly as a result of stabilizer consumption in the photooxidative process. These changes in CL parameters were found to correlate with carbonyl index determined by FTIR spectroscopy. [ABSTRACT FROM AUTHOR]

The effect of hindered amine stabilisers (HAS) on the thermal oxidation of low-density polyethylene (LDPE) films subjected to various gamma radiation doses in the range of 68–812 kGy, was studied by chemiluminescence (CL) at 190 °C in the presence of air. Different types of HAS were used, commercially known as Tinuvin 123, Sanduvor PR31 and Uvasil 299. It was found that under CL conditions, an antioxidative effect occurs for all unirradiated samples, being more relevant in the case of Sanduvor PR31. Our results indicate a specific decrease in the stability (depending on HAS nature) of irradiated materials with increasing irradiation dose. The initial intensity of CL emission (I0), which is related to the concentration of radiation-induced peroxy species was plotted as a function of dose and led to straight line dependence with the slope values placing the HAS effectiveness in the sequence: Tinuvin 123 > Sanduvor PR31 > Uvasil 299 ≫ none. [Copyright &y& Elsevier]

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]

Tensile and viscoelastic properties of poly(3‐hydroxybutyrate‐co‐ 3‐hydroxyhexanoate) (PHBHHx)/zinc oxide nanoparticles (ZnO‐NP) bionanocomposites prepared by melt compounding at various ZnO‐NP content ratios, i.e., 1.5, 3, and 6 wt% are investigated. The study of the comprehension of structure‐properties relationships with respect to filler content allows to define an optimized composition of PHBHHx/ZnO. The results indicate that the incorporation of ZnO‐NP led to improved tensile and viscoelastic properties overall the composition range, being however, much higher at 3 wt%. Nevertheless, the increase in both storage modulus (E′) and tensile modulus observed at 3 wt% is detrimental to flexibility and toughness compared with neat PHBHHx and the other PHBHHx/ZnO bionanocomposites. [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]

The article reports some experimental data on the effects of three types of clay: organo-modified montmorillonite (cloisite 30B (C30B)), sepiolite (SP9), and halloysite nanotubes (HNT) on the morphology and physicomechanical properties of polycaprolactone (PCL)/clays bionanocomposites prepared by melt compounding. The clays were incorporated separately into the PCL matrix at a loading rate of 5.00 wt%, which corresponds to 2.91 ± 0.53, 2.42 ± 0.02, and 2.68 ± 0.13 vol% for C30B, SP9, and HNT, respectively. Scanning electron microscopy analysis showed good dispersion of both C30B and SP9 in the polymer matrix, while the presence of a few HNT aggregates was observed on the fracture surface of the PCL bionanocomposite. Furthermore, the HNT aggregates were randomly dispersed. The results indicated an enhancement of the rheological and tensile properties of the PCL bionanocomposite samples filled with C30B and SP9 compared to those containing HNT. Indeed, it was shown an increase in Young's modulus of PCL from 450 ± 16 MPa to 563 ± 42 MPa, 645 ± 68 MPa, and 502 ± 66 MPa for PCL bionanocomposites loaded with C30B, SP9, and HNT, respectively. On the other hand, the thermal stability of the whole PCL bionanocomposite samples was reduced being, however, more pronounced for those containing HNT. The decomposition temperature recorded at 5.00 wt% loss (T 5%) indicated 384.7 ± 0.9 for neat PCL, while the PCL bionanocomposites filled with C30B, SP9, and HNT exhibited the values of 357.3 ± 0.5, 353.2 ± 0.9, and 368.4 ± 0.4, respectively. [ABSTRACT FROM AUTHOR]

Films-based bionanocomposites have gained a great importance in food plastic packaging because they are eco-friendly materials and have the potential to improve food protection, while limiting the accumulation of synthetic plastics on the planet. In this paper, biofilms were prepared using poly(3-hydroxybutyrate- co -3-hydroxyhexanoate) (PHBHHx) reinforced with Zinc oxide nanoparticles (ZnO-NPs) to develop new bionanocomposite materials intended for food packaging. The samples were fabricated using first solvent casting method followed by melt compounding at various loading rates, i.e., 1.5, 3 and 6 wt%. The obtained results showed that the incorporation of ZnO-NPs to PHBHHx at 3 wt% leads to higher crystallinity, improved mechanical properties and antimicrobial activity, compared with neat polymer and other bionanocomposites. This was attributed to the finer and homogeneous nanofiller dispersion in the polymer matrix evidenced by scanning electron microscopy analysis. Whereas at 6 wt%, the bionanocomposite sample exhibited low mechanical properties due to the formation of ZnO-NPs aggregates. In view of the obtained results, the study highlights the potential of using the PHBHHx/ZnO-NPs bionanocomposite at 3 wt% in food packaging without any prior filler treatment. [Display omitted] • ZnO-NPs were successfully incorporated in PHBHHx matrix. • The good dispersion of ZnO-NPs acted as a nucleation agent of the crystallinity. • The new prepared bionanocomposite showed excellent mechanical properties. • ZnO-NPs addition enhanced the antimicrobial activity of the bionanocomposites. [ABSTRACT FROM AUTHOR]

Blends of poly (3-hydroxybutyrate- co -3-hydroxyvalerate) (PHBV) and poly (butylene succinate) (PBS) (50:50 w/w) were prepared by melt mixing. 5 wt% of compatibilizing agent, obtained by grafting of maleic anhydride onto PHBV, was used to improve the miscibility between the blend components. The influence of the presence of both sepiolite and compatibilizer was studied by evaluating the effect of repeated extrusion cycles (up to 6) on the morphology and the functional properties of materials. Changes in thermal, morphological, rheological and mechanical properties were investigated. All the results showed that PHBV is the more sensitive component towards recycling due to thermomechanical degradation, but PBS as well as sepiolite and compatibilizer play a stabilizing role on PHBV due to improved morphology. The mechanical characteristics measured at different scales remain more or less constant compared to the initial ones revealing the preservation of the mechanical properties of the different samples after reprocessing. This paper highlights a synergistic effect induced by the presence of both compatibilizer and sepiolite leading to an improved recyclability of the resulting materials compared to neat polymers. [ABSTRACT FROM AUTHOR]

Blends of poly(3-hydroxybutyrate- co -3-hydroxyvalerate) (PHBV) and poly(butylene succinate) (PBS) with different PHBV/PBS weight ratios (100/0, 75/25, 50/50 and 0/100) were elaborated by melt mixing. The morphological investigation of the different samples, in comparison with that of neat PHBV and neat PBS, pointed out that PHBV/PBS blends form a biphasic system over the whole composition range. Low amount of compatibilizing agent (5 wt%), obtained by grafting maleic anhydride (MA) onto PHBV, i.e. PHBV-g-MA, was used for improving the miscibility between the two components of the blend. The incorporation of a fibrous filler as the sepiolite, easily dispersible in a polymer matrix, was also investigated. The morphology of the different blends as well as the evolution of their material properties were discussed in terms of the sepiolite and compatibilizing agent contents. The dispersion of PBS in the PHBV matrix markedly became finer with incorporation of sepiolite and PHBV-g-MA, due to enhanced interactions between the components. This paper highlighted a synergistic effect induced by the presence of both compatibilizer and sepiolite leading to an improved miscibility of the two blend components. The resulting properties were correlated with the morphology observed for the different blends. [ABSTRACT FROM AUTHOR]

Blends of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(butylene succinate) (PBS) at different weight ratios (80/20, 50/50 and 20/80 w/w) and ternary PHBV/PBS/halloysite nanotubes (HNT) nanocomposites were prepared by melt compounding. Typical co-continuous and nodular morphologies were obtained with the neat blends. The effect of maleic anhydride-grafted PHBV (PHBV-g-MA) compatibilizer and HNT on the nodular microstructure and thermal properties of PHBV/PBS/HNT nanocomposites was investigated. Morphological observations using scanning electron microscopy (SEM) showed an improved dispersion of PBS nodules in the immiscible PHBV/PBS 80/20 blends, owing to the diffusion and emulsifying effect of PHBV-g-MA chains at the PHBV/PBS interface. A preferential location of HNTs in the PBS nodules was observed, due to their better wettability with PBS phase. Image analysis showed that combining HNT and compatibilizer led to a reduced emulsifying effect, attributed to the formation of PHBV-g-MA/HNT aggregates that limit the diffusion of PHBV-g-MA chains at the interface. Thermogravimetric analysis (TGA) and Pyrolysis Combustion Flow Calorimetry (PCFC) showed a better thermal stability and fire reaction of PHBV in the PHBV/PBS blends as compared to neat PHBV. Incorporation of HNT in the blends decreased their thermal stability but improved significantly their fire reaction, whereas combining PHBV-g-MA and HNT seems to level the influence of each component. [ABSTRACT FROM AUTHOR]

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/organo-modified montmorillonite (OMMT) nanocomposite films were prepared by melt compounding and cast-film extrusion at various loading rates, i.e. 1, 3 and 5 wt. %. The effect of OMMT on the biodegradability of produced PHBV nanocomposite films was investigated under controlled conditions in aqueous medium (20 °C for 28 days) by monitoring the biochemical oxygen demand (BOD), and under laboratory-scale composting conditions (58 °C for 70 days) by monitoring the weight and surface loss. The microstructural and macromolecular changes were monitored during the biodegradation process by means of scanning transmission electron microscopy (STEM), differential scanning calorimetry (DSC) and size exclusion chromatography (SEC) analysis. The initial microstructure of the nanocomposites samples exhibited an intercalated structure with a good clay/matrix affinity. BOD evolution in aqueous conditions as well as surface and weight loss in composting conditions indicated that the biodegradation rate of PHBV nanocomposites was lower than neat PHBV, which supports a barrier effect of OMMT. This was confirmed by the surface erosion observed through SEM accompanied by a significant decrease of the average molecular weight in the bulk of the films. Our results demonstrated that the biodegradation of PHBV and nanocomposite films occurred by combined hydrolytic and enzymatic processes, at the surface as well as in the bulk of the material. DSC analysis also revealed no change in the degree of crystallinity, which suggests that the amorphous and crystalline phases were degraded at same rate. [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]

Abstract: The oxidative degradation of neat polylactide (PLA) and PLA-Cloisite 30B (C30B) nanocomposites under gamma irradiation was studied for irradiation doses ranging from 0 to 200 kGy. The morphologies and the properties of neat PLA and PLA-C30B nanocomposites (5 wt.%) were investigated using Fourier transform infrared spectroscopy (FT-IR), size exclusion chromatography (SEC), differential scanning calorimetry (DSC), thermogravimetric analysis (ATG), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nanoindentation measurements. The results were analysed by comparing the C30B influence on the PLA degradation. Results show neat PLA is strongly degraded by gamma irradiation while PLA-C30B nanocomposites are less affected because gamma irradiation promotes the C30B layer distribution within the PLA matrix. The morphological defects were much less more pronounced for the PLA nanocomposites compared to neat PLA, for which many voids and cracks were observed after irradiation. [Copyright &y& Elsevier]

In this work, we propose new mathematical models describing the kinetic degradation of unstabilized low-density polyethylene (LDPE) and LDPE stabilized with hindered amine light stabilizers (HALS). The samples were exposed to natural weathering conditions, and the degradation was measured by a change in elongation at break with time. The mathematical approach developed was based on multiple linear regression analysis (MLRA). We tested the reliability of the selected models using four statistical criteria: residual variance, coefficient of determination, Student test and Fisher-Snedecor test. The linear systems resulting from the MLRA were solved using the Cholesky method. The results showed that the polynomial models developed to predict elongation at break were reliable for both types of samples under natural weathering conditions. The experimental half-life times are close to those predicted by the models. [ABSTRACT FROM AUTHOR]

Pyrolysis and fire behaviour of palygorskite (Pal) fibrous clay (5 wt%) reinforced polyamide 11 nanocomposites prepared by melt compounding were investigated in combination with melamine polyphosphate (MPP). Palygorskite was modified by 3-amino-propyl-triethoxysilane (APTES). Thermal stability and combustion behaviour of the materials were studied by thermogravimetric analysis (TGA), pyrolysis combustion flow calorimeter (PCFC) and cone calorimeter. TGA data showed that MPP reduced the thermal stability of PA11 nanocomposites, whereas the addition of both unmodified and modified palygorskite improved this property. Further, the cone calorimeter and PCFC results indicated a significant decrease in the peak of heat release rate (pHRR) and the total heat release (THR) of PA11 nanocomposites. This also means that the PA11 combustion was strongly reduced in the presence of combined Pal with MPP, being however more pronounced for the modified palygorskite. The improved fire behaviour could be attributed to a synergistic effect between Pal and MPP. • The potential use of Algerian palygorskite as flame retardant. • Combination of palygorskite with melamine polyphosphate (MPP) to improve fire retardancy properties of PA11. • Good insolating effect of palygorskite, in particular in combination with MPP to reduce the flammability of PA11. [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]

Biocompostable composites based of ethylene‐co‐vinyl acetate (EVA) copolymer were prepared by using a twin‐screw extruder. The compatibility between EVA/starch composites were improved either by addition of polyethylene‐grafted maleic anhydride (PE‐g‐MA), or by reactive extrusion with maleic anhydride (MA) and benzoyl peroxide. The crystallinity of the non‐compatibilized composites increased with the starch content. The addition of PE‐g‐MA increased the crystallinity of the composites made with up to 20 wt% of starch. The thermal stability of EVA/starch composites decreased with increasing the starch content, and the addition of PE‐g‐MA compatibilizer enhanced the thermal stability of the composite. The in‐situ grafting with MA and PBO led to an increase in the thermal stability of the composites containing higher amounts of starch. Further, the mechanical properties of the compatibilized EVA/starch composites were improved with increasing the starch content and this was ascribed to the improved interfacial interactions between starch and EVA. POLYM. COMPOS., 40:3242–3253, 2019. © 2019 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Halloysite nanotubes (HNTs) were functionalized by grafting styrene-ethylene-butylene-styrene (SEBS) copolymer chains after a two-step modification procedure. Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA) and pyrolysis–gas chromatography–mass spectrometry (Py-GC/MS) were used to determine the grafting rate. Then, raw and functionalized halloysites were incorporated into polyamide-11(PA11)/ styrene-ethylene-butylene-styrene grafted maleic anhydride (SEBS-g-MA) blends (85/15 w/w). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) micrographs show a good dispersion of both halloysites particles and SEBS-g-MA nodules in the PA11 matrix. In the case of functionalized halloysite, the presence of HNTs bundles surrounded with fine SEBS-g-MA nodules is observed. Atomic force microscopy (AFM) also highlighted the different blends morphologies. Incorporation of functionalized halloysite leads to an improvement of the thermal properties without affecting the PA11 crystallization. Moreover, mechanical performance, especially toughness, was highly improved in the presence of functionalized halloysite due to a good stress transfer from the matrix to the modified halloysite agglomerates surrounded by SEBS-g-MA. [ABSTRACT FROM AUTHOR]