Polymer composites reinforced with natural fibers and nanocellulose in the automotive industry: a short review

Environmental concerns and cost reduction have encouraged the use of natural fillers as reinforcement in polymer composites. Currently, a wide variety of reinforcement, such as natural fibers and nanocellulose, are used for this purpose. Composite materials with natural fillers have not only met the environmental appeal, but also contribute to developing low-density materials with improved properties. The production of natural fillers is unlimited around the world, and many species are still to be discovered. Their processing is considered beneficial since the natural fillers do not cause corrosion or great wear of the equipment. For these reasons, polymer reinforced with natural fillers has been considered a good alternative for obtaining ecofriendly materials for several applications, including the automotive industry. This review explores the use of natural fillers (natural fibers, cellulose nanocrystals, and nanofibrillated cellulose) as reinforcement in polymer composites for the automotive industry323172016/09588-9; 2016/09588-9; 2016/09588-9CAPES - Coordenação de Aperfeiçoamento de Pessoal e Nível SuperiorCNPQ - Conselho Nacional de Desenvolvimento Científico e TecnológicoFAPESP – Fundação de Amparo à Pesquisa Do Estado De São Paul

Nanocellulose/bioactive glass cryogels as scaffolds for bone regeneration

A major challenge exists in the preparation of scaffolds for bone regeneration, namely, achieving simultaneously bioactivity, biocompatibility, mechanical performance and simple manufacturing. Here, cellulose nanofibrils (CNF) are introduced for the preparation of scaffolds taking advantage of their biocompatibility and ability to form strong 3D porous networks from aqueous suspensions. CNF are made bioactive for bone formation through a simple and scalable strategy that achieves highly interconnected 3D networks. The resultant materials optimally combine morphological and mechanical features and facilitate hydroxyapatite formation while releasing essential ions for in vivo bone repair. The porosity and roughness of the scaffolds favor several cell functions while the ions act in the expression of genes associated with cell differentiation. Ion release is found critical to enhance the production of the bone morphogenetic protein 2 (BMP-2) from cells within the fractured area, thus accelerating the in vivo bone repair. Systemic biocompatibility indicates no negative effects on vital organs such as the liver and kidneys. The results pave the way towards a facile preparation of advanced, high performance CNF-based scaffolds for bone tissue engineering

Transdisciplinarity in a bio-engineering course

In order to face environmental issues related to resource management and the protection of our ecosystems, future engineers must be aware of the need to develop new sustainable technologies. Our multidisciplinary and transdisciplinary course aims at sensitizing students to the major challenges related to the environment and resources. In particular, bio-engineering for the production of biosourced and biodegradable polymer materials, waste treatment and recovery, as well as ecosystems remediation are addressed. The aim of the lectures, in the first part of the course, is to introduce notions of ecology, biotechnology, polymer materials and process engineering, in order to prepare the project part which allows students to develop achievements on bio-based materials. The students choose from four project areas: the design and construction of a biodegradation reactor, the production of enzymes by genetic modification of bacterial strains, the implementation and optimization of biodegradation processes, the development and transformation of polymer materials, in particular bio-based and biodegradable materials. Finally, students are invited to consider the importance of interactions between complementary disciplines for the success of sustainable and responsible complex projects such as those in the field of bio-engineering

An improved process for the surface modification of SiO2 nanoparticles

Qu’elle soit ordinaire ou d’exception, la justice est au cœur du projet révolutionnaire, en 1789, en 1793 ou en 1795. Pour construire une cité nouvelle, changer ses cadres et veiller à son bon fonctionnement, il faut un droit, des institutions et des hommes en partie nouveaux, qui assurent le maintien de l’ordre public et la résolution des conflits civils. À chaque étape majeure de la Révolution, ses acteurs en sont convaincus ; à chaque étape, ils traduisent leur conviction dans un ensemble ..

The Role of Fluorinated IL as an Interfacial Agent in P(VDF-CTFE)/Graphene Composite Films

International audienceThe incorporation of graphene into a polymer matrix can endow composites with extended functions. However, it is difficult to well disperse pristine graphene into a polymer matrix in order to obtain polymer nanocomposites due to the lack of functional groups on the surface for bonding with a polymer matrix. Herein, we investigated the role of fluorinated ionic liquid (IL) as a new interfacial agent in poly(vinylidene fluoride-co-chlorotrifluoroethylene) (P(VDF-CTFE))/graphene composite films. First, a task-specific IL, perfluorooctyltriphenylphosphonium iodide (IL-C8F13), was synthesized and adsorbed on the surface of graphene oxide (GO) and reduced graphene oxide (rGO) for making functional nanofillers which were capable of being incorporated into the P(VDF-CTFE) matrix. The cation structure of IL combined three phenyls (potential π–π interactions with graphene) and a short fluorinated chain (enhanced miscibility with fluorinated matrix via dipolar interactions) to make a compatible graphene filler and P(VDF-CTFE) matrix at the interface among them. Second, two series of P(VDF-CTFE)/GO-IL and P(VDF-CTFE)/rGO-IL composites with different loading contents were prepared with the goal of providing an understanding of the mechanism of interfacial interactions. This paper investigated the difference in the interaction model between GO with IL and rGO with IL. Subsequently, the interfacial effect of IL on the properties of P(VDF-CTFE)/graphene composites, such as crystallization, chain segmental relaxation behavior, dispersion, and the final dielectric properties will be further studied

Understanding of Versatile and Tunable Nanostructuration of Ionic Liquids on Fluorinated Copolymer

International audienceA fundamental understanding of the versatile and tunable nanostructuration effect of two phosphonium ionic liquids (ILs), denoted octadecyltriphenylphosphonium iodide (IL-C18) and tributyl(methyl)phosphonium methylsulfate (IL-108), on a semicrystalline fluorinated copolymer poly(vinylidene fluoride-co-chlorotrifluoroethylene) (P(VDF-CTFE)) was elaborated. This research suggests that the nanostructuration mechanism is very dependent on the diffusion and interacting abilities of ILs in matrix, which are determined by the chemical structures of ILs. Both LLs appear to diffuse and regularly assemble in the rigid amorphous fraction (RAF) of P(VDF-CTFE) between crystalline lamellae thanks to the "template" confinement effect of 2D structure. The assembled structure shows a gradually regular ID to 2D geometric evolution with increasing the ILs amount revealed by Porod exponents in SANS analyses. Simultaneously, these regularly assembled ILs in the RAF also act as "template" to efficiently induce a complete transition of nonpolar alpha-phase to polar gamma- and/or beta-phase with only a tiny amount of ILs (from 2 wt %) (by XRD and FTIR). Moreover, the crystallization displays a depression behavior with reduced T-c, T-m, crystallinity (by DSC), and crystallite size (by SANS) due to the existence of ILs in the RAF seen as obstacle for the regular chain-folding and the dipolar interaction with P(VDF-CTFE). We propose that the synergistic influence of mutual "templates" endues phosphonium ILs a versatile nanostructuration on the fluorinated matrix. Moreover, this versatile nanostructuration effect can be easily tuned by tailoring the chemical structures of ILs. The difference in the chemical structures of ILs endows them different diffusion rates upon crystallization from solution for preparing resulting blend films and strengths of dipolar interaction with P(VDF-CTFE), consequently affecting their dispersion state in the matrix to reside in the RAF with different extents and interacting abilities (confirmed by IDEA and DMA). Thus, IL-108 with faster migration rate and stronger dipolar interaction than IL-C18 (due to the smaller steric hindrance and extra polar groups in the cation/anion combination of the IL structure) locates in the RAF much more to induce more trans-configuration (beta-phase), more homogeneous dispersion morphology, and higher depression of crystallization

Synthesis of 1-[1H,1H,2H,2H-perfluooctyl]-3-[2-(oxiran-2-yl)ethyl]imidazolium 4-[(2-oxiran-2-yl)ethoxy]benzenesulfonate as a New Perfluorinated Ionic Monomer

International audienceAccess to perfluorinated compounds represents a growing challenge in the academic and industrial fields to achieve target compounds with specific physico-chemical properties. Especially, the insertion of a perfluorinated chain within an ionic liquid can provide improvements not just in terms of hydrophobicity and lipophobicity, but also viscosity, density as well as thermal stability. In this research area, we have recently developed new access points to several epoxy imidazolium salts combined with fluorinated anions such as bistriflimide (NTf2−), hexafluorophosphate (PF6−) or tetrafluoroborate (BF4−). Here, we reported the synthesis of a perfluorinated imidazolium cation associated with a sulfonate anion as a new functionalized partner. This sequence required four steps from imidazole (cationic part) and three steps from sodium 4-hydroxybenzenesulfonate (anionic part), respectively. This perfluorinated ionic liquid was fully characterized by nuclear magnetic resonance with 1H-NMR, 19F-NMR, 13C-NMR, DEPT, COSY, HSQC, HMBC and IR spectroscopy. The two parts of the salt were confirmed by high-resolution mass spectrometry (HRMS), and we combined thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) to determine the thermal properties of this new compound

Polymer and ionic liquids : a succeeded wedding

International audienc

Polymer and ionic liquids : a succeeded wedding

International audienc