The invention relates to a method for producing rubber crumb comprising: a) suspending rubber granules of a given size in an autoclave (1) containing a supercritical fluid; b) stirring the mixture for a predetermined time and at constant pressure and temperature; c) carrying out an isenthalpic expansion of the mixture of step b) by spraying it through a nozzle (20).

A new supercritical co-injection process has been developed to coat microparticles. The process was first set up with micron-sized glass beads as model particles and then applied to two powdered active pharmaceutical ingredients. A lipid was used as coating material. The mass balance core/shell in the obtained particles was performed using both differential scanning calorimetry (DSC) and pycnometry measurements and showed a good reproducibility of the process when particles above 20 mu m size were considered. Fourier transform infrared (FT-IR) spectra and environmental scanning electronic microscope (ESEM) characterization were used to ensure that a shell of coating surrounded the raw particles. Both methods showed a different deposition mode of the lipid between the coated particles and a physical mixture of glass beads and lipid. Release tests in distilled water performed with coated active compounds showed a slowed down dissolution kinetics. The study of the polymorphism of the crystallized lipid revealed a solid/solid transition with time. The supercritical co-injection process is a promising way to discretely coat particles with relatively low diameters (20-50 mu m) and is particularly suited to coat sensitive pharmaceutical molecules such as proteins. (C) 2007 Elsevier B.V. All rights reserved.

The upcoming depletion of fossil fuels calls for the development of alternative energies produced from renewable resources. Particularly, energy valorisation of agriculture and food processing wastes is one of the most promising tools for renewable energy production. The amount of food wastes is rapidly increasing due to urbanisation, industrialisation and population growth worldwide. They consequently represent a widely available resource, and their use as a raw material allows reducing the environmental cost associated with their disposal. These resources usually have high moisture content, making dry valorisation processes unattractive because of a costly drying step prior to conversion. Hydrothermal processes are conversely particularly well suited for the valorisation of wet organic wastes in an economical way, since they use water as the reaction medium. More specifically, liquid fuels can be produced using hydrothermal liquefaction (HTL). The process converts wet biomass into a crude-like oil with higher heating values up to 40 MJ/kg using subcritical water (T=250-370 degrees C, P=10-30 MPa). Though this is an active research area, the mechanisms of hydrothermal liquefaction still remain unclear today. Some processes have already been developed at the pilot scale for valorising food processing wastes. However, the development of HTL processes at industrial scales is facing technological and economic challenges. This paper discusses the two main issues to address for development of the process at large scales. On the one hand, hydrothermal conversion of food processing residues and model compounds is necessary to better understand the fundamentals of hydrothermal liquefaction. As well, technological and process integration issues have to be addressed to ensure economic viability of commercial HTL processes. (C) 2015 Elsevier Ltd. All rights reserved.

Equilibrium data of the solubility of carbon dioxide in Precirol(R) ATO5, Compritol(R) 888 ATO and Gelucire(R) 43-01, three solid lipid carriers suitable for controlled/sustained delivery, were measured by a static analytical method for three different temperatures each, in a pressure range from 10 to 20 MPa. The influence of the presence of carbon dioxide in the melting point of the lipid matrices was also studied by a visual method for pressures up to 30 MPa. All the compounds studied presented a similar behaviour in the presence of carbon dioxide, showing a decrease in the melting points between 5 and 13 degrees C, whereas the solubility of carbon dioxide varies from 0.3 to 0.5 g/g of lipid compound. These results are of utmost importance to design supercritical fluid processes for particle formation at lower operating costs. (C) 2006 Elsevier B.V. All rights reserved.

Thermochemical processes are promising ways for energy valorization of biomass and waste, but suffer from a lack of predictability. In this work, we focus on using model molecules to model the behavior of wet organic residues during hydrothermal liquefaction (HTL), a process used to produce bio-based liquid fuels from wet biomass. Monomeric and polymeric model molecules were used as modelling tools to study HTL of real resources. Experiments with model mixtures and four food processing residues (blackcurrant pomace, raspberry achenes, brewer's spent grains, grape marc) were conducted at 300 degrees C, 60 min holding time and a dry matter concentration of 15 wt%. To elaborate model mixtures, four model monomers (glucose, guaiacol, glutamic acid, linoleic acid) and two model polymers (microcrystalline cellulose, alkali lignin) were selected from characterization of blackcurrant pomace. HTL of model mixtures reproduced HTL of blackcurrant pomace with acceptable representativeness, but results showed that model mixtures should include polymers to represent the fiber content of the resource. Results of HTL of model compounds were used to elaborate polynomial correlations able to predict experimental yields as a function of the initial biomass composition. Calculations were within -8.0 to +4.8 wt% of experimental yields obtained by HTL of real food processing residues, showing a good accuracy of the correlations. These expressions also showed good agreement with HTL results reported in the literature for other resources, and could be useful to assess the potential of various kinds of bioresources for HTL.

The invention concerns a method for producing particles (20, 21) at least partly crystallized, under pressure, comprising reciprocal dissolving of at least one fluid under higher or slightly lower pressure than its critical pressure with at least one substance to be treated, in a dissolving zone (2), followed by rapid depressurization with at least one depressurizing means (12) downstream of said dissolving zone (2) so as to collect said particles (21), at least partly crystallized, in the collecting zone (3) located downstream of said depressurizing means (12), said substance to be treated comprising the butterfat. Said method is characterized in that it further consists in collecting particles (20) at least partly crystallized in the dissolving zone (2). The invention also concerns a device (1) for implementing said method.

Hydrothermal liquefaction (HTL) refers to the conversion of carbonaceous resources into oily substances in hot pressurized liquid water. During this process, constitutive biomass molecules decompose into thousands of organic compounds, following complex reaction mechanisms. The chemistry behind HTL processes is highly complex and still poorly understood to date, in spite of many research efforts. After a detailed analysis of a wet bioresource, blackcurrant pomace, a selection of representative model compounds was subjected to hydrothermal liquefaction conditions (300 degrees C, 60 min), either alone or as binary, ternary and quaternary mixtures: glucose, xylose, and microcrystalline cellulose were chosen to represent carbohydrates; guaiacol and alkali lignin for native lignin; glutamic acid for proteins; and linoleic acid for lipids. The results show that the reaction products mainly arise from degradation of individual compounds. The main reactions that can be identified are decarboxylation, dehydration, and condensation reactions producing heavy compounds found in the bio-oil and the char. Some binary interactions have been identified such as the Maillard reaction between carbohydrates and proteins, and also a strong interaction between carbohydrates and lipids for bio-oil formation. Comparative experiments showed that HTL of the real resource (blackcurrant pomace) could be qualitatively represented by model mixtures, in terms of the molecular composition of the products, especially when model fibres were used. The quantitative representativeness of the simulating monomers is lower than that obtained by using model polymers.

A new bone tissue process using supercritical carbon dioxide extraction was evaluated for viral inactivation and the allografts produced by this process were tested in an in vivo implantation experiment. Four viruses, human immunodeficiency virus type I (HIV-1), Sindbis virus, Polio Sabin type I virus and Pseudorabies virus (PRV) were assayed. Four processing stages, supercritical CO2, hydrogen peroxide, sodium hydroxide and ethanol treatments were also tested. The efficiency of the process was assessed in terms of reduction factors which are the log10 of the ratio of the virus load before and after the stage to be evaluated. The cumulated reduction factors were the following: > 18.2 for Sindbis virus, > 24.4 for Poliovirus, > 17.6 for PRV and > 14.2 for HIV-1. Such allografts processed in this way were implanted into sheep leading to a much faster osseointegration in comparison with non-treated allografts. The combination of better graft incorporation and viral safety suggest that this process could become a new way for processing bank bones, alternatively or additionally, to the procedures presently used.

In the manufacturing process of pasta or couscous, durum wheat semolina agglomeration comprises successive steps, in particular a wetting and hydration stage. In this step, interactions between water molecules and semolina grains contribute to the agglomeration properties. Hydration properties of semolina have been recognised to play an important role in agglomeration. The hydration properties of semolina have been characterised using various methods which can be divided into 2 groups according to the water addition: liquid or vapour. Several parameters can be used to describe hydration properties and hydration mechanisms, such as: water sorption capacity, hydration kinetics, diffusion of water within the solid (swelling, dissolution, solid-water affinity and thermodynamic properties). In this study, sorption isotherms and diffusion coefficients have been determined by gravimetric method in specific conditions. The immersion enthalpy of the semolina and its main sub-components, starch and gluten have been measured by mixing micro-calorimetry. Hydration thermodynamic properties, Gibbs free energy, enthalpy and entropy, were calculated from these experimental data. It was found that hydration by vapour or liquid water is an exothermic reaction. The determined diffusion coefficient was used to estimate the stabilisation time of water within the solid. Being high at low relative humidity, the diffusion coefficient decreases during progressive saturation of solid sites. Sorption energy and solid-water affinity yield information about the type of interaction between water molecules and solid sites. The drop in the sorption energy during the increase in water content can be attributed to a decrease in solid-water interactions. The hydration energy of durum wheat semolina in vapour or liquid water was found to be low. This corresponds to the energy input needed to generate contact between water and grain surface and for mixture homogenisation. (C) 2011 Elsevier Ltd. All rights reserved.

Forming complexes with cyclodextrins can enhance the dissolution rate, the stability, the solubility and the bioavailability of a drug. In this work, piroxicam/beta-cyclodextrin complexes were prepared at solid state by means of supercritical carbon dioxide. The influence of temperature, residence time, water content and a ternary agent, L-lysine, were studied. The complex was characterized by Differential Scanning Calorimetry, Scanning Electronic Microscope and dissolution profile in water. Finally, a complete inclusion was achieved for a piroxicam/beta-cyclodextrin/L-lysine mixture by keeping a physical mixture of the three compounds (1:2:1.5 molar ratio) for 2 h in contact with CO2 at 150 degrees C and 15 MPa. (C) 2008 Elsevier B.V. All rights reserved.

The residence time distribution (RTD) of a flowing polymer through a single screw extruder was studied. This extruder allows injecting supercritical carbon dioxide (scCO(2)) used as physical foaming agent. The tested material is Eudragit E100, a pharmaceutical polymer. RTD was measured at various operating conditions and a model describing RTD has been developed. High screw speed or high temperature implies short residence time, but these parameters do not have the same effect on polymer flow. In the flow rate range studied, scCO(2) has no significant influence. A mathematical model consisting of a plug flow reactor in series with a continuous stirred tank reactor (CSTR) cross-flowing with a dead volume fitted well the experimental data. (C) 2008 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

This study presents the development of an improved technique for viscosity measurements under high pressure. The apparatus is based on the principle of the falling ball viscometer, implemented in a high-pressure autoclave fitted with visualisation windows. The originality here is that the balls fall through a tube open at both ends with a diameter slightly greater than that of the balls, allowing a simplified modelling and numerical simulation. A numerical approach has been used for viscosity determination. Calculations have been made with COMSOL Multiphysics (R) with the laminar Navier-Stokes model for Newtonian mixtures. It includes the specific hydrodynamic effects without the need for a calibration fluid. However, validation experiments were carried out at atmospheric pressure with dimethylsulfoxide (DMSO) at 298,308 and 318 K and with cocoa butter at 313 and 353 K, with values of viscosity in the range from 1.4 to 45.4 mPa s. Comparative measurements with literature data have been conducted with cocoa butter saturated with carbon dioxide at 313 and 353 K and for pressures ranging from 0.1 to 25 MPa. At 313 K, viscosity varies from 45.4 mPa s to 3.1 mPa s while at 353 K it varies from 12.4 to 1.9 mPa s. For both isotherms tested, within the range 0-15 MPa, the higher the CO(2) dissolution in the cocoa butter, the lower the viscosity. However, this decrease in viscosity is more pronounced at the lowest temperature. Above 15 MPa the CO(2) dissolution effect on viscosity becomes insignificant, i.e. within the experimental error, due to a counter effect linked with the high hydrostatic pressure. Furthermore, the limits of use of this method have been determined. This technique is revealed as reliable and can therefore be used with other binary systems. (C) 2010 Elsevier B.V. All rights reserved.

Structured and fully bio-based polymer assemblies based on chitosan micro- and nano-particles and poly(lactic acid) (PLA) were developed using a continuous cast-film extrusion process. The microstructure and thermal properties of the resulting biocomposite films are studied. Dispersion and size distribution of chitosan particles within the films were analyzed by optical microscopy and laser diffraction. Results show a homogeneous dispersion with no particles agglomeration, due to favorable physico-chemical interactions between chitosan particles and PLA and weak particle cohesion within the agglomerates. Differential scanning calorimetry experiments evidence a pronounced nucleating effect as well as an enhanced crystal growth rate, and a great increase in crystallinity of PLA in the presence of chitosan particles. Furthermore, in the case of chitosan nanoparticles, no reduction of PLA molecular weight occurred as revealed by gel permeation chromatography. The dispersion of nanosized chitosan particles in PLA thus appears to be an efficient way to control its crystallization behavior without degrading its molecular characteristics. POLYM. ENG. SCI., 59:E350-E360, 2019. (c) 2018 Society of Plastics Engineers

It is well known that supercritical carbon dioxide (sc-CO(2)) is soluble in molten polymers and acts as a plasticizer. The dissolution of sc-CO(2) leads to a decrease in the viscosity of the liquid polymer, the melting point and the glass transition temperature. These properties have been used in several particle generation processes such as PGSS (particles from gas saturated solutions). It is therefore highly likely that extrusion processes would benefit from the use of sc-CO(2) since the rationale of the extrusion processes is to formulate, texture and shape molten polymers by forcing them through a die. Combining these two technologies, extrusion and supercritical fluids, could open up new applications in extrusion. The main advantage of introducing sc-CO(2) in the barrel of an extruder is its function as a plasticizer, which allows the processing of molecules which would otherwise be too fragile to withstand the mechanical stresses and the operating temperatures of a standard extrusion process. In addition, the dissolved CO(2) acts as a foaming agent during expansion through the die. It is therefore possible to control pore generation and growth by controlling the operating conditions. This review focuses on experimental work carried out using continuous extrusion. A continuous process is more economically favourable than batch foaming processes because it is easier to control, has a higher throughput and is very versatile in the properties and shapes of the products obtained. The coupling of extrusion and supercritical CO(2) technologies has already broadened the range of application of extrusion processes. The first applications were developed for the agro-food industry 20 years ago. However, most thermoplastics could potentially be submitted to sc-CO(2)-assisted extrusion, opening new challenging opportunities, particularly in the field of pharmaceutical applications. This coupled technology is however still very new and further developments of both experimental and modelling studies will be necessary to gain better theoretical understanding and technical expertise prior to industrial use, especially in the pharmaceutical field. (C) 2010 Elsevier Ltd. All rights reserved.