With the mandatory separation of bio-waste at source compostable packaging could be treated in industrial composting stations be get out of their waste status and be converted in a valuable product, a compost used as soil fertilizer. However, compost can be considered as a potential source of soil contamination with nano and microplastics. To date, there is no standardized method for detecting and quantifying nano and microplastics in compost. The objective is to develop an efficient and non- destructive extraction protocol to identify and quantify biodegradable and conventional nano and microplastics present in compost by FTIR and Raman microspectroscopies, and thermal analysis (Pyr‐ GC-MS).The micro and nanoplastics were first extracted from the inorganic compounds present in the Compost complex matrix using the density difference using CaCl2 (d=1.4). The organic compounds present in the compost were eliminated by oxidative digestion using hydrogen peroxide H2O2 at 30%. Depending on their chemical fingerprint and after optimization microplastics were identified and quantified by number and mass (estimation by calculation using area, volume and density) by FTIR microspectroscopy and nanoplastics by Raman microspectroscopy. Pyr-GC-MS was used to quantify the polymer type in plastic.A method to extract microplastics from compost was optimized and validated with a recovery rate greater than 92% which proves extraction efficiency without significantly affecting the physical and chemical integrity of microplastics. Biodegradable nano and microplastics were analyzed well identified from a compost sample with a correlation coefficient at least greater than 70% compared to the internal library containing reference spectra of known materials and the analysis time is relatively short (4 hours per sample for FTIR) similar to that found by other authors and much longer for Raman.In this study, for the first time, a simple and efficient method for extracting biodegradable microplastics from compost was optimized and validated. Comparison of several analytical approaches using IR and Raman micro spectroscopy and thermal analysis was also proposed for identification and quantification.

With the compulsory separation of biowaste at source from January 2024 (in France and Europe), some compostable packaging could be processed in industrial composting plants in association with food waste. In line with the circular economy strategy, they could thus be transformed from waste into compost, a soil improver. In this context, an exhaustive experimental analysis of the transient and persistent degradation products generated by conventional and biodegradable plastics in this complex organic matrix is essential. Used as an organic soil improver in the agricultural sector, biowaste compost is a lignin-rich organic waste product that can be considered a potential source of microplastic soil contamination. To date, there is no standardized method for detecting and quantifying microplastics in compost. This study led to the development of an efficient, non-destructive preparation protocol for quantitatively extracting biodegradable and conventional nano and microplastics from compost. To identify and quantify the microplastics obtained, FTIR and Raman microspectroscopies were used alongside thermal analysis (Pyr-GC-MS). A critical comparison of these different methodologies is proposed.

Rubber-based nanocomposites prepared by solid-phase mixing with precipitated silica or carbon black are typically strongly aggregated systems with different levels of spatial organization, as highlighted by our group in the past [1, 2]. Our strategy is to investigate such systems based on the study of simplified industrial samples with ingredients limited to a strict minimum. Small-angle X-ray scattering (SAXS) can then be used to study the filler microstructure in rubber nanocomposites with different filler loading. The size and mass of primary particles and small aggregates are determined using a model of inter-aggregate polydisperse hard sphere interactions based on a correlation hole analysis. Another key feature of rubber nanocomposites is the influence of filler surfaces on polymer dynamics, and an original application of dielectric spectroscopy to measure the adsorption isotherm of coating agents on silica embedded in the polymer matrix will be presented. [3]A major advance was then to couple SAXS measurements on synchrotron beamlines with in-situ shear rheology to provide microstructural evidence for macroscopic rheological effects, which leads to disruption of the filler network and subsequent flocculation. The Payne effect has been characterized in rubber nanocomposites filled with carbon black, but with only small signatures in the scattering under oscillatory shear. In parallel, we have also coupled shear rheology with fast acquisition dielectric measurements to follow the change in electrical conductivity due to the destruction/formation of conductive pathways.References:[1]G. P. Baeza, A.C. Genix, C. Degrandcourt, L. Petitjean, J. Gummel, M. Couty, J. Oberdisse, Macromolecules, 2013, 46, 317–329. doi: 10.1021/ma302248p[2]D. Musino, A.C. Genix, C. Fayolle, A. Papon, L. Guy, N. Meissner, R. Kozak, P. Weda, T. Bizien, T. Chaussée, J. Oberdisse, Macromolecules, 2017, 50, 5138–5145. doi: 10.1021/acs.macromol.7b00954[3] D. Musino, J. Oberdisse, M. Sztucki, A. Alegria, A.C. Genix, Macromolecules, 2020, 53, 8083–8094. doi: 10.1021/acs.macromol.0c01506.

Rubber-based nanocomposites prepared by solid-phase mixing with precipitated silica or carbon black are typically strongly aggregated systems with different levels of spatial organization, as highlighted by our group in the past [1, 2]. Our strategy is to investigate such systems based on the study of simplified industrial samples with ingredients limited to a strict minimum. Small-angle X-ray scattering (SAXS) can then be used to study the filler microstructure in rubber nanocomposites with different filler loading. The size and mass of primary particles and small aggregates are determined using a model of inter-aggregate polydisperse hard sphere interactions based on a correlation hole analysis. Another key feature of rubber nanocomposites is the influence of filler surfaces on polymer dynamics, and an original application of dielectric spectroscopy to measure the adsorption isotherm of coating agents on silica embedded in the polymer matrix will be presented. [3] A major advance was then to couple SAXS measurements on synchrotron beamlines with in-situ shear rheology to provide microstructural evidence for macroscopic rheological effects, which leads to disruption of the filler network and subsequent flocculation. The Payne effect has been characterized in rubber nanocomposites filled with carbon black, but with only small signatures in the scattering under oscillatory shear. In parallel, we have also coupled shear rheology with fast acquisition dielectric measurements to follow the change in electrical conductivity due to the destruction/formation of conductive pathways.

Microemulsions are thermodynamically stable phases of typically oil and water, and a surfactant covering the interface between them. In this chapter, we review their basic properties, starting with molecular properties and curvature, and relating them to Winsor phases and the Kahlweit-Strey fish phase diagram. The underlying physics based on surfactant properties allows understanding of, e.g., counter-intuitive evolutions of conductivity caused by transitions from a water-continuous phase to disconnected water droplets by adding water. Small-angle scattering has been a method of choice for quantitative investigations of the structure of microemulsions. Some guidelines for analysis based on absolute units, specific surface, curvature, power laws, characteristic sizes, and dilution laws will be given before focusing on detailed modeling. Phases of droplets in a continuous matrix can be understood as swollen (possibly inverse) micelles or colloids, and examples using contrast variation and an analysis based on colloidal form and structure factors will be discussed in this chapter. The existence of bicontinuous phases has triggered considerable interest in the past, and only the combination of self-diffusion NMR, electron microscopy, and small-angle scattering provided a complete picture. Small-angle neutron scattering with contrast variation has provided both pure interfacial film scattering, and the structure of the interwingled bulk phases. While the quantity of the surfactant film surface is accessible in the high-q Porod domain, curvature corrections allow determining its bending properties. The description of the bulk phases by various geometrical or thermodynamical models is also reviewed. Starting with the Debye-Büche expression for inhomogeneous solids, which has only one characteristic length, the well-known Teubner-Strey expression with two length scales will be discussed. Geometrical models based on tessellation of space, starting with the cubic cell model, and extending to DOC-models based on disordered Voronoi polyhedra can be used to distribute the available volumes and surfaces, for different connected geometries based on lamellae or cylinders. The generation of random volumes using level cut plane waves or wavelets will close the discussion of available families of models. This introductory chapter is rounded up with an outlook to current research in the field, from nano- to macroemulsions. Depending on the bending stiffness of the surfactant film, new structures and concepts have emerged.