Stability and safety of wastes-based packaging materials (EcoBioCAP-WP 4)

National audienc

Mechanical Properties of Starch-Based Nanocomposites

This chapter reports the mechanical properties of starch‐based nanocomposite materials, considering that the starchy material can be used either as the continuous polymeric phase (matrix), or the nanodispersed phase (filler), or both. The first section of the chapter discusses the reinforcing effect of the different fillers used to improve the mechanical properties of thermoplastic starch, that is, inorganic clays, carbon nanotubes, and polysaccharide‐based (cellulose, starch) nanoparticles and attempts to give a critical comparison of the different reinforcements The second section talks about the reinforcing effect of starch nanocrystals, as well as the mechanisms proposed to explain it

Urban parks and gardens green waste: A valuable resource for the production of fillers for biocomposites applications

International audienceUrban parks and gardens green waste constitute a low-cost and highly available lignocellulosic-rich resource, that is currently treated in composting or anaerobic digestion processes. The present work investigated for the first time the potential of using urban green waste as raw resource for the production of lignocellulosic fillers by dry fractionation (combination of sorting and grinding processes). Five fractions of lignocellulosic fillers with controlled composition were produced: a branches-rich fraction, a grasses-rich fraction, a leaves-rich fraction, and two fractions constituted of a mixture of constituents. All the fractions were ground to reach an average median diameter around 100 μm. The reinforcing effect of each fraction was investigated and compared to that of the sample as a whole. Biocomposites based on a poly(3-hydroxybutyrate-co-3-hydroxyvalerate) as matrix were produced by melt extrusion, with filler contents up to 30 wt%. It was shown that the branches-rich fraction displayed the best reinforcing effect (e.g. stress at break of 37 ± 1 MPa for a filler content of 15 wt%, similar to that of the neat matrix) whereas the grasses-rich fraction slightly degraded the overall mechanical performance (e.g. stress at break of 33.5 ± 1.5 MPa for a filler content of 15 wt%). The dry fractionation and formulation steps could be thus adapted depending on the targeted application, e.g. by choosing to use the whole urban green waste resource, or to remove grasses, or to keep only branches

Mitigating the Impact of Cellulose Particles on the Performance of Biopolyester-Based Composites by Gas-Phase Esterification

International audienceMaterials that are both biodegradable and bio-sourced are becoming serious candidates for substituting traditional petro-sourced plastics that accumulate in natural systems. New biocomposites have been produced by melt extrusion, using bacterial polyester (poly(3-hydroxybutyrate-co-3-hydroxyvalerate)) as a matrix and cellulose particles as fillers. In this study, gas-phase esterified cellulose particles, with palmitoyl chloride, were used to improve filler-matrix compatibility and reduce moisture sensitivity. Structural analysis demonstrated that intrinsic properties of the polymer matrix (crystallinity, and molecular weight) were not more significantly affected by the incorporation of cellulose, either virgin or grafted. Only a little decrease in matrix thermal stability was noticed, this being limited by cellulose grafting. Gas-phase esterification of cellulose improved the filler’s dispersion state and filler/matrix interfacial adhesion, as shown by SEM cross-section observations, and limiting the degradation of tensile properties (stress and strain at break). Water vapor permeability, moisture, and liquid water uptake of biocomposites were increased compared to the neat matrix. The increase in thermodynamic parameters was limited in the case of grafted cellulose, principally ascribed to their increased hydrophobicity. However, no significant effect of grafting was noticed regarding diffusion parameters

Poly(3-hydroxybutyrate-co-hydroxyvalerate) and wheat straw fibers biocomposites produced by co-grinding: Processing and mechanical behavior

International audienceThe main objective of this work was to explore for the first time the potential of the co-grinding process using a high-energy vibrated ball mill to prepare poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/wheat straw fibers biocomposites. Grinding conditions of virgin PHBV pellets were examined by focusing on the evolution of particle size, morphology, crystallinity, and molecular weight. Temperature and grinding duration were demonstrated to be the key parameters affecting PHBV milling. In a second step, mechanical properties of biocomposites prepared by cryo-co-grinding were discussed in relation to the processing conditions and the resulting structure of materials. Comparing to virgin PHBV, the reinforcing effect of wheat straw fibers was very poor, regardless of the good dispersion of fibers within the polymer matrix induced by co-grinding. The increased brittleness and decreased toughness of biocomposites were attributed to (a) a poor interfacial compatibility between wheat straw fibers and PHBV and (b) the degradation of PHBV during processing, as revealed by the decrease in molecular weight

Physical-Chemical and Structural Stability of Poly(3HB-co-3HV)/(ligno-)cellulosic Fibre-Based Biocomposites over Successive Dishwashing Cycles

International audienceIn order to lengthen the life cycle of packaging materials, it is essential to study their potential for reuse. This has been never carried out for emerging bio-based and biodegradable materials such as PHBV/(ligno-)cellulosic fibre-based biocomposite materials. This work therefore highlights the impact of successive dishwashing cycles on the physical-chemical and structural stability of such materials. Several parameters were considered to assess this stability, such as the visual aspect and colour, the microstructure, the thermal and tensile properties, and the overall migration in food liquid simulants. The effect of fibre composition, morphology, and content was investigated by selecting three types of commercial (ligno-)cellulosic fibres and two filler contents (20 and 40 wt%). A great potential for reuse of PHBV films was highlighted by their high stability after up to at least 50 dishwashing cycles. However, the addition of (ligno-)cellulosic fillers negatively impacts the stability of PHBV-based materials, especially due to the hygroscopic behaviour of (ligno-)cellulosic fillers and the heterogenous microstructure of biocomposites, with at best up to 10 possible dishwashing cycles for ultra-pure cellulose. In conclusion, reuse including dishwashing steps can be considered for neat PHBV materials, while this should be prohibited for PHBV/(ligno-)cellulosic fibre-based biocomposite materials

Biodegradablity of ecofriendly nano-biocomposite materials for controlled release applications

International audienc

Influence of processing temperature on the water vapour transport properties of wheat gluten based agromaterials

Contact: fax: +33 04 6714 4990. E-mail addresses: [email protected], [email protected], [email protected], [email protected] audienceThe influence of processing conditions (thermoforming temperature) on water vapour transport properties (permeability, sorption and diffusion) of wheat gluten-based films was studied in relation to structural properties (cross-linking degree of the wheat gluten matrix). Increasing temperature from 80 °C to 120 °C led to a significant decrease in material swelling in high moisture environment and a WVP reduction mainly due to a decrease in diffusivity but without important effect on the moisture sorption isotherms. This was attributed to a higher cross-linking degree of protein network for film thermoformed at 120 °C, with a limited mobility and less possibilities of rearrangement in high moisture conditions

Réduction de l'impact de l’utilisation des produits phytosanitaires: Contrôle de la libération dans le sol par un granulé protéique biodégradable nanocomposite

International audienc

How olive pomace can be valorized as fillers to tune the biodegradation of PHBV based composites

International audiencePolyhydroxybutyrate-co-valerate (PHBV) is a very promising bio-sourced and biodegradable bacterial polyester, the commercial development of which being limited by its high cost. On the other hand, olive oil extraction generates a large amount of lignocellulosic solid residue, called olive pomace (OP), whose disposal raises environmental concerns, including the inhibition of soil microbial populations and the reduction of seed germination. To address these issues, PHBV/OP based biocomposites were produced (at a filler content of 15 wt%) using three different fillers obtained by dry fractionation of OP, i.e. a stone-rich fraction (SF), a pulp-rich fraction (PF) and a crude pomace (F0). The objective of the present work was to investigate how the composition of OP-based fillers influenced the biodegradability of resulting biocomposites. The biodegradation of PHBV, OP-based fillers and OP/PHBV-based biocomposites was assessed by respirometric tests conducted in a standardized soil environment over 4 months. Results showed that the incorporation of OP-based fillers in PHBV favored the overall biodegradability of the materials. Indeed, 100% of biodegradation was achieved after 75, 79 and 87 days for PHBV-F0, PHBV-SF and PHBV-PF formulations respectively, while a biodegradation rate of only 91% was obtained after 123 days in the case of neat PHBV. These results were discussed in the light of several parameters such as the material structure, the affinity of the fillers for the matrix, the composition and the degree of crystallinity of the filler, together with the antibacterial activity of the OP samples assessed by a direct contact technique on solid medium