Grenoble Institute of Technology

About: Grenoble Institute of Technology is a education organization based out in Grenoble, France. It is known for research contribution in the topics: Hyperspectral imaging & Geology. The organization has 3427 authors who have published 5345 publications receiving 137158 citations. The organization is also known as: Grenoble INP.

Morphological investigation of nanoparticles obtained from combined mechanical shearing, and enzymatic and acid hydrolysis of sisal fibers

Abstract: The goal of this work was to prepare cellulosic nanoparticles using different processing routes, viz. a combination of mechanical shearing, acid and enzymatic hydrolysis. It was shown that the enzymatic hydrolysis pretreatment of bleached sisal pulp helps the preparation of well individualized rod-like nanocrystals. The morphology of cellulose fibers and nanoparticles was determined by scanning and transmission electron microscopies, respectively. The main outcome of this study indicated the usefulness of the enzymatic treatment for cellulose nanocrystals production. The enzymatic treatment allowed production of a broad range of cellulosic nanoparticles. This investigation proved that the distinction between MFC and whiskers to describe such cellulose nanoparticles is not sufficient. Indeed, it appears essential to indicate the pretreatment performed.

Physical and/or Chemical Compatibilization of Extruded Cellulose Nanocrystal Reinforced Polystyrene Nanocomposites

Abstract: Impressive mechanical properties and reinforcing capability make cellulose nanocrystal (CN) a promising candidate as biomass nanofiller for the development of polymer-based nanocomposites. With the recent announcement of large-scale CN production, the use of industrial processing techniques for the preparation of CN-reinforced nanocomposites, such as extrusion, is highly required. However, low thermal stability of sulfuric acid-prepared CN limits the processing since most polymeric matrices are processed at temperatures close to 200 °C or above. It has been proved that surface adsorption of polymers on CN as compatibilizer, such as hydrophilic polyoxyethylene (PEO), can improve its thermal stability due to the shielding and wrapping of PEO. However, the weak combination between CN and PEO allows the free movement of surface polymer, which can induce the self-aggregation of CN and microphase separation in composites especially during melt processing. Using carboxylation–amidation reaction, short chains pol...

Flexibility and Color Monitoring of Cellulose Nanocrystal Iridescent Solid Films Using Anionic or Neutral Polymers

Abstract: One property of sulfated cellulose nanocrystals (CNCs) is their ability to self-assemble from a concentrated suspension under specific drying conditions into an iridescent film. Such colored films are very brittle, which makes them difficult to handle or integrate within an industrial process. The goal of this study is (i) to produce flexible films using neutral poly(ethylene glycol) (PEG) and (ii) to modulate their coloration using an anionic polyacrylate (PAAS). The first part is dedicated to studying the physicochemical interactions of the two polymers with CNCs using techniques such as zeta potential measurements, dynamic light scattering (DLS), quartz crystal microbalance (QCM), and atomic force microscopy (AFM). Iridescent solid films were then produced and characterized using scanning electron microscopy (SEM) and UV-visible spectroscopy. The mechanical and thermal properties of films incorporating CNC were measured to evaluate improvements in flexibility. The addition of 10 wt % of PEG makes these films much more flexible (with a doubling of the elongation), with the coloration being preserved and the temperature of degradation increasing by almost 35 °C. Up to 160 μmol/gCNC PAAS can be added to tune the coloration of the CNC films by producing a more narrow, stronger coloration in the visible spectrum (higher absorption) with a well-pronounced fingerprint texture.

Cellulose modified fibres in cement based composites

Abstract: The objective of the present work is to evaluate the effect of surface modification of cellulose pulp fibres on the mechanical and microstructure of fibre–cement composites. Surface modification of the cellulose pulps was performed with Methacryloxypropyltri-methoxysilane (MPTS) and Aminopropyltri-ethoxysilane (APTS) in an attempt to improve their durability into fibre–cement composites. The surface modification showed significant influence on the microstructure of the composites on the fibre–matrix interface and in the mineralization of the fibre lumen as seen by scanning electron microscopy (SEM) with back-scattered electron (BSE) detector. Accelerated ageing cycles decreased modulus of rupture (MOR) and toughness (TE) of the composites. Composites reinforced with MPTS-modified fibres presented fibres free from cement hydration products, while APTS-modified fibres presented accelerated mineralization. Higher mineralization of the fibres led to higher embrittlement of the composite after accelerated ageing cycles. These observations are therefore very useful for understanding the mechanisms of degradation of fibre–cement composites.