The incorporation of representative commercial compostable materials into a full-scale open-air windrow composting process in an industrial site using household-separated biowaste was investigated. Two batches out of the same initial biowaste mixture were studied, one as control and the other containing initially 1.28 wt% of certified compostable plastics. No significant differences in the composting process were revealed. Compostable plastics exhibited a 98 wt% mass loss after 4 months, aligning with industrial composting times. The evolution of the morphology of the materials unveiled polymer specific degradation mechanisms. Both Safety requirements for organic farming were met. Ecotoxicity tests showed no adverse effects, agronomic fertilizing and amending quality was high, the materials compost even enhancing barley growth. The ecological impact assessment demonstrated an advantage for composting over incineration for seven of the eight indicators. In conclusion, this study shows the successful integration of compostable materials into industrial composting, upholding product safety and quality.

Lignocellulosic by-products are frequently disposed by means of combustion. This study investigates an alternative route for corn cob and Kraft lignin resources in order to support circular economy. The respective plantbased fibres and filler were compounded for the first time together with a poly(lactic acid) (PLA) matrix. Consecutively, seven different biocomposites were processed by injection-moulding and further characterized. The biocomposite containing a mixture of Kraft lignin and corn cob (12 wt% in total) exhibited the highest flexural strength (84 MPa). A proper wetting of PLA onto the corn cob particles demonstrated a good compatibility at matrix/fibre interface. PLA molecular structure changed in presence of 20 wt% lignin filler, with effect on the glass transition temperature and on the composite mechanical strength. The fibres moderately influenced composites surface tension, while Kraft lignin contributed to a slight increase of surface hydrophobicity. Surface energy (sigma sTotal) of composites have been estimated at 27.6, 28.7 and 27.8 mN/m for PLA/KL-20, PLA/CC-10 and PLA/KL-15/CC-5 respectively. While the polar component (sigma sPolar) have been estimated at 17.8, 20.0 and 18.7 mN/m for PLA/KL-20, PLA/CC-10 and PLA/KL-15/CC-5 respectively. Unlike the PLA/corn cob composite, those containing Kraft lignin were entirely biodegraded within 2 months in industrial composting conditions study. The materials could be utilized for end-use products thanks to their good mechanical and thermal properties. By adding wood-lignin and corn by-products, materials cost and carbon footprint shall decrease in comparison to pure PLA, while being a biodegradable and sustainable replacement of polyolefins.

With the increase of the global population, the demand for plastic materials in every aspect of life and industry has become tremendous, the packaging sector being the first to both use plastics and produce plastic wastes, whose a great part will irremediably end up in ocean [1]. To face the environmental issues stemming from the accumulation of conventional plastics, biodegradable plastics, whether they derive from renewable feedstocks or petroleum, are seen as promising alternatives. Among the biodegradable plastics suitable for replacing conventional plastics, the family of aliphatic polyesters PHAs and PBS are both interesting candidates for satisfying the functional requirements of a daily use plastic with a low environmental impact.

Biodegradable plastics appear as one promising means to help solving the increasing issue of environmental pollution by plastics. The present study aims at comparing the biodegradation mechanisms of two promising biodegradable plastics, PHBV Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and PBSA Poly(butylene succinate-co-adipate) with the objective to provide a better understanding of the mechanisms involved and identify the most relevant indicators to follow biodegradation. For this purpose, the progress of the biodegradation process was monitored under controlled composting conditions at the laboratory scale at 58 degrees C using several methodological approaches for evaluating polymer degradation. Indicators of the extent of material disappearance based on respirometry and mass loss measurements were combined to other indicators evidencing the morphological, structural and chemical modifications induced at the surface or in the bulk of the material as surface erosion by SEM, decrease of molecular weight by GPC, crystallinity changes by DSC and chemical changes by ATR-FTIR. As expected, both polymers were rapidly biodegraded in less than 80 days. However, in spite of its higher molecular weight and degree of crystallinity, PHBV degraded faster than PBSA, which led to suggest that different biodegradation mechanisms would be involved. At this regard, a two-phase scenario was proposed for each polymer on the strength of all the degradation-induced changes observed at the polymer surface and in its bulk. Based on these two scenarios, the discrepancy in biodegradation rate between PHBV and PBSA would be essentially attributed to significant differences in crystals morphology and spatial organization of both polymers. Regarding the relevance of the different indicators studied, mass loss stood out as the most relevant and accurate indicator to assess the disappearance of material especially when combined with respirometry and mineralization kinetics assessment. Besides, indicators focusing on the surface changes as SEM, AFM and POM were emphasized since seen as powerful tools to evidence morphological changes at different scales. At last, changes in thermal properties as crystallinity rate and melting temperature, even if complex to interpret due to the wide range of interdependent mechanisms they bring into play appeared as inescapable tools for improving the understanding of the underlying mechanisms involved in polymer biodegradation. (C) 2019 Elsevier Ltd. All rights reserved.

Ageing of various plastics in marine environment was monitored after immersion of two synthetic (polyvinylchloride, PVC, and polyethylene terephthalate, PET) and one biodegradable (poly(butylene adipate co-terephtalate), PBAT) plastics for 502 days in the bay of Lorient (Brittany, France). Data analysis indicates that aged PVC rapidly releases estrogenic, compounds in seawater with a later adsorption of heavy metals; PET undergoes a low weakening of the surface whereas no estrogenic activity is detected; PBAT ages faster in marine environment than PVC. Aged PBAT exhibits heterogeneous surface with some cavities likely containing clay minerals from the chlorite group. Besides, this degraded material occasionally shows a high estrogenic activity. Overall, this study reports, for the first time, that some aged plastics, without being cytotoxic, can release estrogenic compounds in marine environment.

Elutriation is an efficient process for extracting microplastics. The development of a numerical model has shown the need for optimizing aspects of the design of the actual elutriation protocol as well as the dimensioning of the column to increase its efficiency. The study aims to propose new dimensioning data and protocol elements for designing an efficient column. Using a numerical model, the filling velocity was calculated as a function of the size and the density of the particles to prevent sand suspension. The sieving protocol was adapted to increase the density limit for the extraction of plastic particles from 1460 to > 1800 kg.m(-3). The durations of the elutriation and the column height were calculated to improve the control of the particle suspension. These results contribute to the development of the next generation of elutriation system and will accelerate the study of plasticome in the context of sandy sediments.

As plastic particles are one of the most commonly waste found on beaches [1], this pollution requires the use of innovative extraction methodologies especially for smallest size ranges of plastic particles, as microplastics.

Certains materiaux ont la possibilite de subir une decomposition naturelle rapide en etant « consommes » par des bacteries, des champignons, des algues, des insectes, etc. C'est donc une alternative au mode de valorisation par recyclage (et donc de recuperation d'energie). Cet article se propose tout d’abord d’expliciter les etapes de la biodegradation en detaillant les principales reactions, les facteurs impliques ainsi que les methodes de mesure utilisees ; sont ensuite presentes les differents materiaux biodegradables issus de polymeres naturels ou artificiels, et les principales applications industrielles des polymeres biodegradables.

Elutriation is an efficient process for extracting microplastics. The development of a numerical model has shown the need for optimizing aspects of the design of the actual elutriation protocol as well as the dimensioning of the column to increase its efficiency. The study aims to propose new dimensioning data and protocol elements for designing an efficient column. Using a numerical model, the filling velocity was calculated as a function of the size and the density of the particles to prevent sand suspension. The sieving protocol was adapted to increase the density limit for the extraction of plastic particles from 1460 to >1800 kg·m−3. The durations of the elutriation and the column height were calculated to improve the control of the particle suspension. These results contribute to the development of the next generation of elutriation system and will accelerate the study of plasticome in the context of sandy sediments.

Evaluating the microplastics pollution on the shores requires overcoming the technological and economical challenge of efficient plastic extraction from sand. The recovery of dense microplastics requires the use of NaI solutions, a costly process. The aim of this study is to decrease this cost by recycling the NaI solutions and to determine the impact of NaI storage. For studying the NaI recyclability, the solution density and the salt mass have been monitored during ten life cycles. Density, pH and salt mass have been measured for 40days to assess the storage effect. The results show that NaI solutions are recyclable without any density alterations with a total loss of 35.9% after the 10cycles of use. During storage, chemical reactions may appear but are reversible. Consequently, the use of recycling methods allows for a significant cost reduction. How far the plastic extraction by dense solutions is representative is discussed.

The elutriation process has shown its efficiency to extract microplastics from sand and began to spread in the scientific community. This extraction technic requires knowing with accuracy the extraction velocities of particles. This study aims to test whether numerical modeling could help to calculate these velocities. From hydrodynamic equations, a numerical model has been developed and the outputs are compared to experimental extraction data. The results show, for the calculated velocities, the experimental plastic extraction yields will be higher than 90% for <10% of sand contamination. The model also allows determining that, with the actual protocol, the maximum plastic density which can be extracted is about 1450kg·m−3 whereas the detrimental resuspension, which may occur during the column filling step, is highlighted. From model calculations, it arises that changes in the column dimensioning and the protocol operations need to be considered.

Three 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.

Although relatively easy to extract in the marine environment, microplastics are very difficult to recover when they are trapped in sediments. The elutriation column is one of the best tools currently available for extracting plastics from sediment, but with a high sand recovery yield. This study aims to address the following questions: (i) is it possible to use a sedimentological approach to limit the sand recovery? (ii) does the extraction velocity of the sand and plastic particles vary according to density and granulometry? (iii) what is the relative recovery efficiency obtained for dense polymer particles mixed with marine sand? Based on a new granulometric classification, different plastic particle-size fractions are defined. Their extraction velocities are experimentally determined on particles of sediment and different plastics (PA, PVC). The particle recovery experiments indicate that it is possible to extract >90% of dense plastic particles in cases of negligible sand recovery.

In the aim of resolving environmental key issues such as irreversible soil pollution by non-biodegradable and non-recoverable polyethylene (PE) fragments, a full-scale field experiment was set up to evaluate the suitability of four biodegradable materials based on poly(butylene adipate-co-terephtalate) (PBAT) to be used as sustainable alternatives to PE for mulching application in vineyard. Initial ultimate tensile properties, functional properties during field ageing (water vapour permeability and radiometric properties), biodegradability and agronomical performance of the mulched vines (wood production and fruiting yield) were studied. In spite of their early loss of physical integrity that occurred only five months after vine planting, the four materials satisfied all the requested functional properties and led to agronomic performance as high as polyethylene. In the light of the obtained results, the mulching material lifespan was questioned in the case of long-term perennial crop such as grapevine. Taking into account their mulching efficiency and biodegradability, the four PBAT-based studied materials are proven to constitute suitable alternatives to the excessively resistant PE material.

In this study, natural degradation and biodegradation of poly(3-hydroxybuyrate-co-3-hydroxyvalerate) (PHBV) films were followed in different marine environments. First of all, ageing of PHBV films was investigated in natural seawater for 180 days and degradation was followed by means of weight loss measurements, scanning electron microscopy (SEM), differential scanning calorimetry and steric exclusion chromatography. In a second part, biodegradation tests were performed on PHBV powder, by following carbon dioxide (CO 2 ) release , to highlight the PHBV bioassimilation of marine microorganisms. Three different marine environments were considered for biodegradation tests: a solid inoculum with foreshore sand, a solid–liquid inoculum with sand and seawater and a liquid inoculum with seawater. In the latter, a biofilm was added to study the influence of microorganisms on biodegradation kinetics. The films aged under natural conditions show a large loss of weight after 180 days in immersion, around 36 %, confirmed by SEM pictures which show an increase of the surface erosion and a decrease of the sample thickness. Microorganisms’ attack occurred as suggested by CO 2 release during biodegradation tests, whatever the environment studied.

The disintegration, biodegradation and ecotoxicity of cross-linked wheat gliadin films with antimicrobial properties were assessed under controlled composting conditions. Gliadins were chemically modified with different percentages of cinnamaldehyde (1.5%, 3% and 5%) increasing their cross-linking degree and imparting antimicrobial activity. After the films were subjected to simulated conditions of use in a food packaging application, they were composted. The most cross-linked gliadin film showed a very fast disintegration profile. It completely disintegrated into fine visually indistinguishable residues after 4 days of being inserted in compost medium. Scanning electron microscopy revealed the rapid microbial colonization of the films' surface. Biodegradation was assessed by measuring the amount of carbon dioxide produced in a static system specifically designed for this study. The cross-linking degree of the proteinaceous matrices modified their biodegradation rate without impairing their complete biodegradation. The presence of residual cinnamaldehyde in the films, which can exert antimicrobial activity, did not hamper their biodegradation neither caused ecotoxicity on tomato seeds germination and plant growth.

The aim of this study is to establish a baseline for poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) lifetime prediction in a marine environment, by means of mechanical and physico-chemical characterization of specimens immersed in continuously renewed and filtered natural seawater in the laboratory at different temperatures (4, 25 and 40 degrees C). Samples were also aged at sea in Lorient harbour in order to compare laboratory and natural degradation mechanisms and kinetics. Due to its morphology, hydrolysis of PHBV in natural seawater is quite slow, and samples were observed to undergo preferentially an enzymatic surface degradation. Increasing the aging temperature in the laboratory promotes the water uptake and causes hydrolysis. As two degradation mechanisms occur in parallel, the choice of test conditions is critical, and the lifetime of PHBV in a marine environment is difficult to predict accurately. (C) 2014 Elsevier Ltd. All rights reserved.