Poly(epsilon-caprolactone)-based nanocomposites containing Cloisite (R) 30B (C30B, polar) and Cloisite (R) 15A (C15A, non-polar) were synthesized via THF-assisted solution blending to investigate polarity-dependent dispersion, functional properties, and biodegradation at 3 and 5 wt% loadings. Structural characterization revealed organoclay-dependent morphologies: 3 wt % C15A promoted partial exfoliation within an intercalated structure, whereas 5 wt % C15A and C30B systems exhibited predominantly intercalated structures with increased aggregation. Rheological assessments revealed pronounced pseudo-solid behavior and elevated storage moduli, particularly in C15A composites, reflecting superior nanofiller dispersion. The incorporation of 5 wt% C15A and C30B into PCL enhanced crystallization, elevating crystallinity from 36.2% (neat PCL) to 39% and 45.9%, respectively. Nanoclay loading (C15A, C30B) significantly reduced water vapor permeability to 0.13 and 0.15 g/m24 hatm, respectively, due to filler-induced tortuosity. Nanoindentation measurements revealed that C15A exhibited superior mechanical properties compared to C30B, with increased modulus (765 MPa) and hardness (57 MPa), suggesting improved matrix-filler compatibility. Biodegradation assays using Aspergillus Niger confirmed accelerated fungal colonization on OMt-PCL surfaces (index 4), compared to neat PCL (index 1), attributed to the catalytic influence of well-dispersed silicate phases. These observations validate the applicability of OMt-PCL nanocomposites in the design of advanced eco-efficient materials, particularly targeting sustainable packaging technologies.

There has been an increasing demand to enhance the energy absorption characteristics of natural fiber-reinforced polymer composites, especially when employed in structural applications. This study focuses on the development of coir fiber-based polypropylene (PP)/ethylene-propylene-diene rubber (EPDM) composites, in which fibers are pre-treated with plasma and coated with extremely hydrophobic fluoroalkyl functional siloxane (FAS). The melt blending technique is employed for the fabrication of these composites. To determine the appropriate length of the coir fibers for composite use, a critical length experiment is conducted. The composition of the composites is set by using 100 parts per hundred (pph) of polypropylene and 7.5 pph of EPDM, while varying the coir fiber content from 10 pph to 40 pph. The newly developed composites exhibit a greater capacity for strain energy absorption, resulting in improved Izod impact energies without significant compromise to the tensile and flexural properties. The impact-fractured specimens were examined using scanning electron microscopy (SEM) and the morphology images reveal key energy absorption mechanisms. Rheological analysis indicates shear-thinning behavior, while DSC analysis shows a lag effect in crystallization. The nucleation activity study shows that the coating (FAS-coated) might not be providing the desired nucleation effect, hindering the nucleation sites for crystallization. TGA analysis indicates that high stability at elevated temperatures achieved for FAS coated coir based composites.

It has been observed that some epoxy resins exhibit the greatest elastic stiffness when not fully cured. In this study, this counter-intuitive resin behaviour (stiffness) is shown to be reflected in the compressive strength of associated epoxy fibre composites. A reduction of up to 30% in both properties can be observed when going from incomplete conversion to complete cure. The Budiansky and Fleck compressive failure criterion (Budiansky and Fleck, 1993) is, in this study, proven to be both qualitative and quantitative in its relevance for describing the reduction in compressive strength. This study is of particular importance to engineers and manufacturers of composites, as the conventional belief is that optimum performance is achieved with a complete cure.

To investigate the efficiency of gemini surfactant based organoclays (OMts) for the stabilization of O/W emulsions, different ammonium gemini surfactants with semi-rigid hydrophobic chains and spacer lengths were used for the modification of sodium montmorillionite (Mt). The composition and morphology of the resulting organoclays were characterized by Fourier transform infraredspectroscopy, X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy and thermogravimetric analysis. The results showed that these surfactants are more efficient than conventional surfactants and hydrocarbon type gemini surfactant analogous in the modification of Mt. An important increase of the d-spacing values was obtained particularly for long hydrocarbon chains and spacers. The OMt's thermal properties and hydrophobicity were also governed by the structure of surfactants. The stabilizing behavior of gemini surfactants, OMt as well as surfactant/OMt mixtures in oil/water (1:1, v/v) emulsions was investigated by macroscopic and microscopic morphological observations. Better stabilization was achieved by G(10-4-10) surfactant bearing decyl chains and OMts with high surfactant concentration.

Biocomposites based on biodegradable polybuty-lene succinate (PBS) and organomodified clays (OMt) were prepared by melt blending process. The OMt nanofillers were obtained by ion exchange reaction between sodium montmor-illonite (Mt) and gemini surfactants bearing 4-decyloxyphenylace-tamide hydrophobic chains and ethylene or hexylene spacer. X-ray diffraction (XRD), scanning electron microscopy (SEM), trans-mission electron microscopy (TEM), and rheological measure-ment results showed that the investigated hybrids present a uniform dispersion with an exfoliation of clay into the PBS matrix, particularly for short spacer surfactant based composites. The effect of organoclay loading and composition on the thermal, mechanical, and barrier properties was also investigated. High clay loading and long gemini surfactant spacer lead to substantial improvement of Young modulus values by 21%, while low clay content induces a reduction of the hybrid's crystallinity due to strong OMt-PBS interactions. Compared to that of the neat PBS film, a significant reduction of the water vapor permeability (WVP) by 28% was obtained by adding only 3 wt % of PBS/OMt (2) which opens up prospects for this material in the field of food packaging. This study shows that gemini surfactant-modified organoclays can be used as effective nanofillers in a PBS matrix to access to value-added nanocomposites.

Because of its weak durability at low temperatures and low strain rates, polypropylene's use as an engineering plastic is restricted. To make polypropylene more tougher, combine it with elastomeric particles in a cost-effective manner is an excellent option. Internal melt blending was used to manufacture polypropylene (PP) and high-molecular-grade ethylene-propylene-diene rubber (EPDM) blends with varying constitutive ratios in this work. EPDM's lower portions have especially high impact strength ratings for PP/EPDM mixtures. (i.e., 2.5, 5, and 7.5 parts per hundred EPDM rubber). The mechanically generated cavitation behavior of impact cracked specimens is obvious from SEM morphology, showing to the strong impact resistance of PP/EPDM blends. Increased EPDM content reduces the amount of scattered EPDM rubber particles by increasing the average diameter of dispersed particles, as seen by HRTEM images of the samples. The tensile and flexural properties of PP/EPDM blends were analysed. The rheological tests demonstrate that as the frequency increases, the complex viscosity drops, indicating that the melt is in a pseudoplastic condition. Due to the destruction of polymer chain mobility at greater cooling rates, DSC analysis indicates that percentage crystallinity values decrease as the cooling rate of crystallization increases, resulting in an incomplete crystallization process. The fact that PP/EPDM mixes have two glass transition temperatures indicates that they are immiscible. An investigation using the TGA found that the maximum degradation temperature (T-max) of the PP/EPDM rubber mixtures may be sustained for long periods of time at very high operating temperatures.

This work focuses on a novel technique based on the spray–dry–cure method to establish a hydrophobic sol–gel coating on a lignocellulosic coir fibre surface. The fibres were first activated with oxygen plasma to ensure spreading of the droplets and thus coating uniformity. The efficiency of this method was highlighted by the high content of fluorine (52.1%) coming from the sol–gel-coated coir fibre revealed by X-ray photoelectron spectroscopy analysis. Scanning electron microscopy showed that the sol–gel coating was uniformly deposited. This had a drastic effect on the coir fibre surface and mechanical properties. The contact angle measurements show that the coir fibre surface becomes extremely hydrophobic after application of the sol–gel coating. The work of adhesion changed from 121.7 to 46 mJ/m 2 . Besides this drastic change into a hydrophobic surface, this study also highlighted the higher average breaking force (from 6.4 to 9.8 N), breaking strength (from 108.1 to 148.3 MPa), modulus (from 1819.1 to 2004.6 MPa) and elongation at break (from 45.9 to 60.4%) when coir fibres are plasma treated and sol–gel coated. This work shows that by using this sol–gel coating treatment, the authors have been able to overcome the major drawbacks of coir fibres, such as moisture absorbency, for their use in industry.

To improve PLA's properties and overcome its drawbacks such us poor thermal stability, resistance and gas barrier properties, several studies have been performed using different nanofillers. In this work, PLA nanocomposites reinforced by three organoclays, OMt(8-4-8), OMt(10-4-10) and OMt(12-4-12) at various weight percentages (1 and 3 wt%) were prepared by melt mixing using a twin-screw extruder. The organoclays were obtained from sodium montmorillionite and gemini surfactants bearing different hydrophobic chain lengths. The resulting nanocomposites have been characterized in terms of composition and morphology by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The thermal stability and cold crystallization behavior were accessed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The effect of clay composition and concentration on the mechanical and rheological properties of the nanocomposites as well as their water vapor permeability has been also investigated. The resulting nanocomposites exhibit a significantly reduced permeability as compared to unfilled PLA and an improved young modulus and toughness at the detriment of ductility.

Every year a considerable amount of olive husk was rejected in nature by different oil mills or incinerated. The valorization of these agricultural wastes by its incorporation as loading in the development of composite materials with polyvinyl chloride (PVC) is the object of this research. To improve the properties of the interface between the polymer matrix and olive husk flour (OHF), two chemical treatment methods were conducted. The first treatment consisted to use PVC-g-MA (maleic anhydride grafted on PVC) as a compatibilizer in composites; the second was a surface modification of olive husk flour by benzoylation. In this context, we prepared various formulations based on polyvinyl chloride/olive husk flour with different loading rates (10, 20, and 30%) using twin-screw extrusion. The Fourier transform infrared was used to study the chemical modification of the fiber. The composites were characterized by mechanical tests, thermogravimetric (ATG/DTG), mechanical dynamic analysis (DMA), and the physical characterization by the water absorption test. The thermogravimetric analysis revealed the improvement of the thermal stability of the composites with and without treatment compared to virgin PVC.

This study aims to investigate the potential of two local fibers, namely El Diss and El Retma, which are abundant in the mountains of North Africa (Sétif, Algeria), to provide cellulose nanocrystals (CNCs). Then, the isolated CNCs from El Diss were used as a reinforcement for a poly(vinyl alcohol-co-ethylene) matrix (EVOH) in the absence and in the presence of borax which was added to improve the interactions between the CNCs and the matrix. The extracted CNCs from both El Diss (CNCD) and El Retma (CNCR) were characterized by Zeta-sizer analysis using dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electronic microscopy. Also, untreated EVOH/CNCD nanocomposites and borax-treated EVOH/CNCD/BOR have been characterized using FTIR, differential scanning calorimetry (DSC) analyses, and by the study of their water absorption behavior. The DLS analysis provided the transversal length of the particles and showed that the surface of the obtained CNCs is negatively charged due to the presence of sulfated ions. Also, FTIR results confirmed the elimination of extra cellulosic substances, whereas TGA proved that the degradation of CNCs occurs at relatively lower temperatures compared with the neat fibers. The incorporation of borax to EVOH/CNCD nanocomposites showed its efficiency in improving the interactions at the interface between EVOH and the CNCD, which significantly affected the material’s thermal properties as concluded from DSC results and their water absorption behavior.

Developing biodegradable formulations or controlled-lifetime polymers is one of the issues of tomorrow. In order to reduce the impact of fishing and to fight the expansion of plastic debris in the marine environment, a new generation of monofilament, resistant and biodegradable, has been developed in this study.

The potential of carbon nanotubes (CNT) as multifunctional filler in poly(epoxy)-based structural composites has been investigated. In a first step the reinforcement effect of CNT has been studied by tensile and three points bending tests, which evidenced significant improvements of stress and strain at break (respectively +17% and +30% for tensile tests on unidirectional carbon fibre-epoxy composites). Moreover, fracture experiments have also revealed a positive effect of CNT on the toughness (G(1c)) of carbon fibres-epoxy composites (+105% of improvement at the initial stage). In a second step, the health monitoring capability quantum resistive strain sensors (sQRS) made of CNT filled epoxy nanocomposite, incorporated in the core of glass fibres-epoxy composites has been studied. It was shown that during cyclic tensile tests, following the evolution of the relative resistance amplitude (A(r)) of sQRS with strain gives a pertinent information on non-reversible phenomena such as plastic deformation and cracks' development within the composite. In particular, the evolution of the sQRS sensitivity (gauge factor GF) under and over the elastic limit, allows to track damage accumulation throughout the composite. These results suggest a possible use of sQRS for the structural health monitoring (SHM) of composites in fields such as boating, wind energy, aeronautics and automotive.

In this work, binary and ternary nanocomposites based on biodegradable polycaprolactone (PCL) reinforced with organo-modified montmorillonites (OMt), epoxy-functionalized graphene (Gr) and their mixtures (OMt/Gr) were prepared using the melt blending process. Two kinds of organoclays having different surfactants were introduced within the matrix, Cloisite® 15A (non-polar) and Cloisite® 30B (polar). In order to study the effect of nanofillers on the matrix properties, rheological tests, morphological, barrier and thermal characterizations were carried out on the hybrid materials. The viscoelastic behavior of PCL based materials was studied using time sweep, amplitude sweep, and frequency sweep tests. The storage modulus of the matrix was improved by adding OMt, and it was further enhanced when OMt is coupled with graphene, especially in the case of the C15A/Gr pair. All the rheological parameters showed that ternary OMt/Gr-PCL mixtures exhibited more pseudo-solid like behavior than binary nanocomposites, reflecting the formation of three-dimensional networks and better distribution of OMt/Gr pairs in the PCL matrix. TEM micrographs confirmed the formation of nanocomposite materials in the case of OMt-PCL and OMt/Gr-PCL. The incorporation of fillers into the biodegradable PCL matrix was significantly improved its permeability toward water vapors. This property is substantially related to the dispersion where a high barrier effect is recorded for ternary OMt/Gr-PCL nanocomposites. The thermal stability of the PCL matrix is affected in the presence of organoclays and/or epoxy-functionalized graphene, giving rise to more thermally stable materials. All the results confirmed that the combination of two nanofillers leads to interesting materials for some applications such as packaging.

Aromatic-containing gemini ammonium bromide surfactants with different spacer length and variable amounts were used to modify Na+-montmorillonite via ion exchange reaction. The resulting organoclays (OMt) were characterized in terms of composition and morphology using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The thermal stability of OMt was determined by thermogravimetric analysis (TGA). The results indicated that gemini surfactants exhibit a good efficiency to modify clay mineral. Surfactant concentration and the length of the spacer connecting the ammonium heads were found to be key parameters governing the thermal stability and the structure of the corresponding OMt. Increasing surfactant concentration and lengthening of the spacer act favorably for the achievement of higher expended interlayer clay structures with better thermal stability. Different configurations of surfactant molecules within Mt interlayers were proposed based on d(001) basal spacing.

In a previous paper, we had evidenced that the memory effect of the resistance of embedded quantum resistive strain sensors (sQRS) could be used to quantitatively assess the damage accumulation in glass fibre reinforced polymers (GFRP). In this work, to comfort this finding and to better understand the mechanisms making sQRS able to monitor the composite's damage, three techniques have been combined to look for correlations during incremental cyclic tensile tests. Experiments were performed on composite samples of different typologies, all instrumented with sQRS in their core. The strain profile measured in the vicinity of defects such as a hole or a notch by digital image correlation (DIC), has been used to determine the strain profile to which the percolated carbon nanotube network based resistive sensors (sQRS) were exposed. Further on, acoustic emission (AE) counts were used to identify the strain level over which damages were recorded to interpret the events detected on the piezo-resistive trace of sQRS, i.e., matrix fracture, interface decohesion, fibres breakage. It is found that sQRS, through the variation of their apparent gauge factor GF, are able to detect strain concentration in their surroundings and to identify damage events in the composite, provided that the fracture behaviour has been previously analysed by AE. Finally, sQRS can keep the memory of the damage accumulated in the composite as their initial resistance shift monitors the non-reversible events associated to damage. Their implementation in composite structures should offer interesting prospects to secure their use by helping to locate stress/strain singularities and potentially anticipate the complete failure.

The quick development of the smart factory and prognostic and health management (PHM), in the fields of aeronautic, automotive and green energies, is evidencing a need for sensors able to monitor the behavior of composite materials all along their life at the closest of the matter. In situ fabricated conductive polymer nanocomposite (CPC) sensors are bringing an interesting solution to this prospect as they can be integrated homogeneously in the core of composites to probe their deformations and damage. In particular fatigue which is one important mode of failure of polymer composites can be monitored from early signs of damage until the final breakage by analyzing the piezo-resistive response of quantum resistive strain sensors (sQRS) made of carbon nanotubes. We have developed all these aspects in the paper taking the example of a classical glass fibers/epoxy composite instrumented in its core with two sQRS to monitor its short and long term fatigue behavior.

In this research work, the prediction of the diffusion coefficient (D p ) of Irganox ® 1076 (Ir‐76) antioxidant in HDPE‐based food contact packaging films was carried out. The diffusion of this additive was studied both, in neat HDPE film and in HDPE nanocomposites films made of HDPE matrix filled with 1, 3, and 5 wt% of a commercially available organoclay (Cloisite ® 15A). The diffusion experiments were carried out by using the Roe's method on films consisting of a stack of several polymer films having a total nominal thickness of 120 ± 01 μm. Diffusion coefficients were determined in the temperature range 80°C to 100°C according to the second Fick's law by measuring the evolution of the Ir‐76 concentration in the films by means of Fourier transform infrared (FTIR) spectroscopy analysis. The results indicated that the diffusion coefficient of Ir‐76 in HDPE films decreased with the addition of the organoclay, and a maximum reduction of 78% (at 23°C) in the diffusion rate of the Ir‐76 was observed at an optimum filler content of 3 wt%, thus making these films attractive for the plastic packaging industry.

The aim of this work is to study the effect of combining organomontmorillonites (Cloisite®15A and Cloisite®30B) with epoxy functionalized graphene on the morphology and different properties of a polylactic acid (PLA)/poly(ε-caprolactone) (PCL) blend. To this end, rheological, morphological, barrier and thermal properties were evaluated. The use of nanofiller mixtures caused significant enhancements in terms of storage and loss modulus of a PLA/PCL matrix, indicating a high degree of co-reinforcement in comparison to that observed when the nanofillers were filled separately. The results from transmission electron microscopy and the non-dependency of the storage modulus in the low frequencies showed that both graphene sheets and clay mineral layers resulted in a fine dispersion and better exfoliation in the PLA/PCL blend matrix. The compatibility of the biodegradable PLA/PCL blend was improved in the presence of organoclays and organoclay/graphene mixtures. PLA/PCL nanofilled blends exhibited higher barrier properties than the pure blend and interesting values were obtained by adding hybrids of organomontmorillonite and graphene, which were linked to their degree of intercalation and also to the existence of synergy between these nanofillers. Melt blending of PLA/PCL and all different nanofillers induced significant improvements of thermal stability. The use of filler mixtures to prepare composite materials is a very interesting way to have the best properties using classical methods of preparation.