Elaboration of polypropylene-clay nanocomposites based on pristine montmorillonite

Cette étude porte sur l’élaboration de nanocomposites à matrice polypropylène (PP) chargée de montmorillonite native (NaMMT). La stratégie retenue est basée sur l’utilisation d’une phase polaire intermédiaire sous forme de mélanges maîtres, dont l’élaboration est réalisée par extrusion avec injection d’eau.Dans une première partie la dispersion de NaMMT et à titre de comparaison de montmorillonite modifiée par extrusion assistée eau dans le polyamide 6 (PA6) a été étudiée grâce à une analyse de la morphologie et de son influence sur les propriétés thermomécaniques. Par la suite, des mélanges maîtres à base de PA6 ont été élaborés par ce procédé et dispersés dans le PP via une compatibilisation réactive. L’analyse de la morphologie, en relation avec les conditions d’élaboration et les performances des mélanges nanocomposites est ensuite présentée.Dans une deuxième partie, un copolymère bloc polyether-bloc-amide (PEBA) a été utilisé comme matrice hôte de NaMMT. Sa dispersion dans le PEBA par extrusion assistée eau a été étudiée par une étude morphologique liée aux propriétés thermomécaniques et aux mécanismes de déformation. Le PEBA a ensuite été utilisé comme phase intermédiaire pour disperser NaMMT dans le PP. L’analyse de la morphologie des mélanges nanocomposites est présentée, en lien avec leurs conditions d’extrusion et leurs propriétés macroscopique.Finalement, la comparaison des résultats obtenus dans le cas des mélanges nanocomposites à base PA6 et PEBA est proposée afin de mettre en évidence le rôle de la polarité de la phase intermédiaire, de la rhéologie des constituants et des conditions de procédé sur les propriétés macroscopiques des matériaux.This work focuses on polypropylene (PP)/clay nanocomposites based on pristine montmorillonite (NaMMT). The elaboration strategy involves the use of a polar polymer based masterbatch to disperse NaMMT in the PP matrix. Water assisted extrusion is used to finely disperse the native montmorillonite in the polar host polymer.In the first part, the dispersion of modified and pristine montmorillonite in polyamide 6 (PA6) using water assisted extrusion is presented. The morphological analysis of the PA6 nanocomposites and its outcome on the thermomechanical properties were studied. PA6 masterbatches were then elaborated using water assisted extrusion and dispersed in PP to obtain nanocomposites blends. Their morphologies are detailed, in relation with the processing conditions, and the related mechanical properties.In the second part, polyether-block-amide (PEBA) was used as host polymer to disperse modified and native montmorillonite. Their dispersion is obtained thanks to the water assisted extrusion process. The morphological analysis and its influence onto the thermomechanical properties and on the deformation mechanisms were studied. PEBA masterbatch were then prepared using water assisted extrusion and dispersed into PP to obtain nanocomposites blends. The study of their morphologies is presented, related to the extrusion conditions, and the corresponding macroscopic performances.Finally, the comparison of the results obtained in the case of PA6 and PEBA nanocomposites blends is discussed to evidence the influence of components rheology and polarity as well as the processing conditions onto the macroscopic behaviors of the materials

Elaboration de nanocomposites à matrice polypropylène chargée d'argile native

Cette étude porte sur l élaboration de nanocomposites à matrice polypropylène (PP) chargée de montmorillonite native (NaMMT). La stratégie retenue est basée sur l utilisation d une phase polaire intermédiaire sous forme de mélanges maîtres, dont l élaboration est réalisée par extrusion avec injection d eau.Dans une première partie la dispersion de NaMMT et à titre de comparaison de montmorillonite modifiée par extrusion assistée eau dans le polyamide 6 (PA6) a été étudiée grâce à une analyse de la morphologie et de son influence sur les propriétés thermomécaniques. Par la suite, des mélanges maîtres à base de PA6 ont été élaborés par ce procédé et dispersés dans le PP via une compatibilisation réactive. L analyse de la morphologie, en relation avec les conditions d élaboration et les performances des mélanges nanocomposites est ensuite présentée.Dans une deuxième partie, un copolymère bloc polyether-bloc-amide (PEBA) a été utilisé comme matrice hôte de NaMMT. Sa dispersion dans le PEBA par extrusion assistée eau a été étudiée par une étude morphologique liée aux propriétés thermomécaniques et aux mécanismes de déformation. Le PEBA a ensuite été utilisé comme phase intermédiaire pour disperser NaMMT dans le PP. L analyse de la morphologie des mélanges nanocomposites est présentée, en lien avec leurs conditions d extrusion et leurs propriétés macroscopique.Finalement, la comparaison des résultats obtenus dans le cas des mélanges nanocomposites à base PA6 et PEBA est proposée afin de mettre en évidence le rôle de la polarité de la phase intermédiaire, de la rhéologie des constituants et des conditions de procédé sur les propriétés macroscopiques des matériaux.This work focuses on polypropylene (PP)/clay nanocomposites based on pristine montmorillonite (NaMMT). The elaboration strategy involves the use of a polar polymer based masterbatch to disperse NaMMT in the PP matrix. Water assisted extrusion is used to finely disperse the native montmorillonite in the polar host polymer.In the first part, the dispersion of modified and pristine montmorillonite in polyamide 6 (PA6) using water assisted extrusion is presented. The morphological analysis of the PA6 nanocomposites and its outcome on the thermomechanical properties were studied. PA6 masterbatches were then elaborated using water assisted extrusion and dispersed in PP to obtain nanocomposites blends. Their morphologies are detailed, in relation with the processing conditions, and the related mechanical properties.In the second part, polyether-block-amide (PEBA) was used as host polymer to disperse modified and native montmorillonite. Their dispersion is obtained thanks to the water assisted extrusion process. The morphological analysis and its influence onto the thermomechanical properties and on the deformation mechanisms were studied. PEBA masterbatch were then prepared using water assisted extrusion and dispersed into PP to obtain nanocomposites blends. The study of their morphologies is presented, related to the extrusion conditions, and the corresponding macroscopic performances.Finally, the comparison of the results obtained in the case of PA6 and PEBA nanocomposites blends is discussed to evidence the influence of components rheology and polarity as well as the processing conditions onto the macroscopic behaviors of the materials.LILLE1-Bib. Electronique (590099901) / SudocSudocFranceF

Food-Grade PE Recycling: Effect of Nanoclays on the Decontamination Efficacy

Although PE-based nanocomposites are gaining interest within the food packaging industry for their outstanding functional properties, their end-of-life has been poorly studied. The lack of identification of such materials suggests that they could end-up in the recycling pathway optimized for the decontamination of un-filled PE. The objective of the present work is to understand and quantify the mechanisms involved in the high temperature desorption of surrogates for PE nanocomposites filled with organo-modified montmorillonite (PNC), compared to conventional PE. An original experimental setup was coupled with a modelling approach to identify the two phenomena involved in the decontamination process: diffusion of the surrogate into the bulk and its evaporation at the surface. A sweep of experimental temperatures enabled the determination of diffusion and evaporation parameters for PE and PNC and the activation energies related to the diffusivity among those two materials. The effects of the introduction of clay nanofillers onto the decontamination process have been explained and recommendations for the recycling pathway have been put forwar

Performance and biodegradability of polymer mulch films after field ageing

International audienc

Polyhydroxyalkanoates / hemp composite for packaging applications: towards a fully integrated extruding process

International audienc

Performance and environmental impact of biodegradable polymers as agricultural mulch films

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Biocomposites From Polyhydroxyalkanoate and Hemp Fibers: Effects of Processing and Compatibilizer on Structure/Performance Relationships.

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Performance and environmental impact of biodegradable polymers as agricultural mulch films

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How Performance and Fate of Biodegradable Mulch Films are Impacted by Field Ageing

International audienceThree black biodegradable films based on PBAT-blends (PBAT/PLA, PBAT/PPC and PBAT/Starch) were tested for vine mulching in real field conditions. The impact of field ageing on their morphology, mechanical performance and ultimate biodegradation was investigated on films exposed at the soil surface or buried into the soil in order to assess the respective contribution of the main related ageing factors i.e. UV radiations and microorganisms. The fact that the soil-facing surface of films exhibited holes 18 months after installation suggested that the biodegradation process could occur above-soil even without previous burying step. However, the early loss of integrity of the biodegradable materials was attributed to UV radiations since beyond a certain threshold the photochemical modifications undergone by the material were too high to sustain its integrity. Whatever the material tested the deterioration of mechanical properties was correlated with the crosslinking of polymer chains inducing the formation of a gel fraction. Considering that the major part of the three materials studied is made of PBAT, the nature of the other polymer constituting the blend would not have a significant impact on the ageing mechanism of the material. Biodegradation analyses conducted in compost medium indicated that field ageing had a low impact on the percentages of mineralization whether the materials had been previously aged or not

Agronomic performances and environmental impact of biodegradable films as an alternative to polyethylene mulches in vineyards.

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