Ce projet contribue à développer la prochaine génération de nano-emballages en utilisant une approche plus sûre et éco-conçue avec des avantages directs à la fois pour l'environnement et la sécurité des consommateurs. Les emballages alimentaires constituent l’un des principaux secteurs d’applications des nanotechnologies avec des enjeux environnementaux prometteurs de substitution des pétro-plastiques par des bio-plastiques et de réduction des pertes et gaspillages alimentaires grâce à des emballages plus performants, de type actifs et intelligents. Dans le cas de matériaux nano-composites (matrice polymérique contenant des nano-particules) destinés au contact alimentaire, le risque majeur en terme de santé humaine est lié à leur impact sur la migration de composés indésirables de l’emballage vers l’aliment (stabilisants UV, antioxydants, plastifiants, etc) qui peuvent avoir des effets néfastes en fonction des doses et durées d’exposition. Ces interactions contenant/contenu sont soumises à une réglementation européenne dont l’objectif est la protection de la santé du consommateur en fixant des limites de migration spécifique pour tous les composés supposés entrer dans la composition des matériaux plastiques dédiés au contact alimentaire. Dans le cas des nanomatériaux, la présence de nanoparticules est susceptible de modifier les interactions entre le polymère et les additifs et par voie de conséquence leurs propriétés de transfert. Ainsi, la formalisation des phénomènes de migration de l’emballage vers l’aliment établie sur des matériaux plastiques ne contenant pas de nanoparticules ne peut pas être directement transposée au nano-matériaux. De plus la présence de ces nanoparticules peut profondément modifier l’éco-toxicité environnementale du système matrice- nanoparticule -additif.La présente étude vise à comprendre et contrôler l’impact des structures nanocomposites (matrice polymérique contenant des nano-particules) sur les propriétés de transport (diffusivité et solubilité) des nanoparticules et des additifs chimiques en condition d’usage. À cet égard, il est nécessaire de combler le déficit de connaissances dans a caractérisation de la structure 3D, des propriétés physico-chimique et des interactions aux interfaces entre nanoparticules et matrice dans les nanomatériaux. Devant la complexité du système étudié, la modélisation est indispensable pour représenter (simplifier sans pour autant perdre trop de connaissances) la structure 3D des nanomatériaux et simuler, reproduire puis prédire, l’évolution de leurs propriétés de transfert en fonction des paramètres structurels et en condition d’usage. La modélisation des transferts est également indispensable pour, dans une approche d’ingénierie inverse, éco-concevoir et dimensionner à façon des nano-emballages sûrs pour l’Homme et l’Environnement. Dans cette optique une démarche de modélisation multi-échelle des relations structure/propriétés de transfert de masse a été mise en place sur des matériaux nanocomposites ciblés choisis pour leur pertinence dans le domaine de l’emballage alimentaire. / The market of nanotechnologies is dominated by the food packaging area which amounts more than 20% of the total nanotechnologies market in 2015. However, the wide-scale use of nanomaterials raises important questions about environmental and safety issues that could hinder their development. In the case of plastics intended to be in contact with food, the risk of contamination concerns not only the nanoparticles but also all the chemical additives added during the material processing. The presence of nanoparticles is susceptible to modify the interactions between polymer and the additives with a possible change in their transport properties and therefore the food contamination.The present work aims at identifying the relationship between the structural characteristic and the transport properties (diffusivity and solubility) of nanoparticles and chemical additives incorporated in nanocomposites. In this regard, it is necessary to fill the gap of knowledge in 3D nanostructure characterization and a multi-scale modeling of mass transfer properties of nanocomposites in real usage conditions.In this way, polyethylene and nanoclay were selected based on the best compromise between real potential applications and the scientific knowledge previously published and eventually the nanocomposites were synthesized with LLDPE, Cloisite20 and a compatibilizer by melt intercalation method.The nanocomposite structure was characterized using TEM, X-ray nanotomography, TGA and XRD then submitted to migration tests undertaken in contact with different food simulants which represent various types of food (aqueous, acid, alcoholic) following the recommendation of the European regulation on the food contact material. To evaluate the positive or adverse effects of the nanomaterials on the contamination of the food by chemical additives which are usually incorporated with the plastic packaging, the virgin polymer and nanocomposite material were spiked with a mixture of the additives exhibiting various volatility, polarity and molecular weight. Then, the transport properties (i.e inertia) of nanocomposite structure was distinctively investigated on kinetic (apparent diffusion coefficient) and thermodynamic (partition coefficient) considerations.The results indicated that nanoclay addition in plastic materials favorably reduced the migration of additives by modifying both their diffusivity in the polymer and their partition between the polymer and the food simulant. However, while the partition coefficient of additives increases in nanocomposite in comparison to pure LLDPE for the samples in contact with all types of food simulants, the reduction of diffusion coefficient is significantly dependent on the nature of the food simulant in contact. Hence, it can be concluded that the major role in the migration of additives is not played by the imposed tortuosity path, but by the factors such as the affinity between the base polymer and simulants as well as the effects of simulants on swelling and crystallinity of the samples. Moreover, the effect of additive-related parameters and the structural parameters were assessed and put in perspective with their impact on the transport properties of nanostructures. Integrating the results of characterization and transfer properties led to an improved understanding of the influence of structure of nanocomposites on their mass transfer properties and therefore on the suitability of using them as food contact materials.

Submitted by JOSIANE SANTOS DE OLIVEIRA (josianeso) on 2018-05-11T15:13:54Z No. of bitstreams: 1 Raquel Von Hohendorff_.pdf: 10228081 bytes, checksum: f4227256dee4ed80e5dd7d192e5b4481 (MD5) / Made available in DSpace on 2018-05-11T15:13:54Z (GMT). No. of bitstreams: 1 Raquel Von Hohendorff_.pdf: 10228081 bytes, checksum: f4227256dee4ed80e5dd7d192e5b4481 (MD5) Previous issue date: 2018-03-16 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Esta Tese tem como tema a gestão dos riscos nanotecnológicos com foco na autorregulação a partir do safe by design, em busca dos objetivos de sustentabilidade do milênio, no contexto da improbabilidade da comunicação inter-sistêmica entre o Direito e Ciência. Atualmente a ampliação do uso das nanotecnologias é uma das principais novidades que vem ocorrendo no setor de produção no mundo inteiro, fazendo parte da Quarta Revolução Industrial, trazendo conjuntamente uma série de preocupações em relação aos aspectos éticos, legais e sociais, bem como acerca dos riscos à saúde e ao meio ambiente. Cabe lembrar que as mesmas características que tornam os nanomateriais diferenciados e benéficos também geram dúvidas e inquietações acerca de seu comportamento especialmente quanto a sua interação com o ecossistema. Em decorrência desta nova realidade, provocada pela ascensão nanotecnológica e seus potenciais riscos, especialmente em relação à saúde humana e ao meio ambiente objetivou-se analisar as possibilidades da contribuição da ferramenta do safe by design, como uma forma de acoplamento entre o Sistema do Direito e o Sistema da Ciência, permeada pelo conceito de pesquisa e inovação responsáveis Responsible Research and Innovation (RRI), preocupada também com os aspectos éticos, sociais e jurídicos - Ethical, Legal and Social Aspects (ELSA), na estruturação autorregulatória regulada da gestão dos riscos nanotecnológicos, visando a sustentabilidade, em seus diferentes aspectos, aplicada à inovação, no contexto dos Objetivos de Desenvolvimento do milênio, projetados pela Organizações das Nações Unidas (ONU) até 2030. Para tanto, utilizou-se a perspectiva metodológica sistêmico-construtivista, a partir das contribuições de Niklas Luhmann, Gunther Teubner e Leonel Severo Rocha, que considera a realidade como uma construção de um observador, analisando todas as peculiaridades implicadas na observação, tratando-se de uma forma de reflexão jurídica sobre as próprias condições de produção de sentido, bem como as possibilidades de compreensão das múltiplas dinâmicas comunicativas diferenciadas em um ambiente complexo, como é o gerado pelas nanotecnologias. Desta forma, o safe by design pode ser entendido como um possível acoplamento estrutural entre os Sistemas da Ciência e do Direito, potencializando a comunicação inter-sistêmica sobre o risco, como uma forma prática e criativa de aplicação das ideias de RRI e ELSA e, mais ainda, como uma modalidade de autorregulação regulada, na gestão dos riscos nanotecnológicos, organizando e estabilizando as expectativas e induzindo comportamentos em busca da sustentabilidade na inovação, no horizonte projetado pelos Objetivos de Sustentabilidade do Milênio. Assim, demonstra-se a necessária imersão do Sistema do Direito na observação sobre risco nanotecnológico, contribuindo com mais um passo rumo à discussão das possibilidades e desafios que o uso das nanotecnologias já está gerando para as atuais e futuras gerações. / This Thesis deals with nanotechnological risk management with a focus on self-regulation based on safe by design, in pursuit of the millennium sustainability goals, in the context of the improbability of inter-systemic communication between Law and Science. Currently, the expansion of the use of nanotechnologies is one of the main innovations that occurring in the production sector worldwide, as part of the Fourth Industrial Revolution, bringing together a number of concerns regarding ethical, legal and social aspects, as well as the risks to health and environment. It should be remembered that the same characteristics, which make nanomaterials differentiated and beneficial, also generate doubts and concerns about their behavior especially regarding their interaction with the ecosystem. As a result of this new reality, provoked by the rise in nanotechnology and its potential risks, especially in relation to human health and environment, the objective was to analyze the possibilities of the contribution of the safe by design tool as a form of coupling between the Law System and the Science System, permeated by the concept of Responsible Research and Innovation (RRI), which is also concerned with - Ethical, Social and Legal Aspects (ELSA), in the self-regulatory structuring of nanotechnology risk management, aiming at the sustainability, in its different aspects, applied to innovation, in the context of the Millennium Development Goals, projected by the UN until 2030. For that, the systemic-constructivist methodological perspective was used, based on the contributions of Niklas Luhmann, Gunther Teubner and Leonel Severo Rocha, considering reality as a construction of an observer, analyzing all the peculiarities involved in the observation, treating it is a form of juridical reflection on the conditions of production of meaning as well as the possibilities of understanding the multiple differentiated communicative dynamics in a complex environment, such as that generated by nanotechnologies. In this way, safe by design can be understood as a possible structural coupling between the Systems of Science and Law, enhancing inter-systemic communication about risk as a practical and creative way of applying the ideas of RRI and ELSA, moreover, as a modality of regulated self-regulation, in the management of nanotechnology risks, organizing and stabilizing expectations and inducing behaviors in search of sustainability in innovation, within the horizon projected by the Millennium Sustainability Goals. Thus, it is demonstrated the necessary immersion of the Law System in the observation on nanotechnological risk, contributing with one more step towards the discussion of the possibilities and challenges that the use of nanotechnologies is already generating for the present and future generations.