BOYER , Séverine A.e.

Polyurethane (PU) foams are widely used in construction, automotive industry, household appliances and other fields. Their low weight and excellent mechanical and thermal insulation properties result from their internal structure. They are sometimes associated to other components to get new polyurethane composites. Structures made from...

In this work, modelling of physical foaming extrusion of LDPE is carried out in order to achieve a better understanding of the mechanisms involved in foam manufacturing. Foaming by extrusion is a four-step process. First, the pellets are introduced and molten in an extruder. Gas is then injected under pressure and dissolved in the polymer...

International audience

International audience

A key problem in the modeling of polyurethane foaming is the determination of relevant physical parameters for the viscosity, the gas expansion and the curing rate. Indeed, it is difficult to measure the chemical kinetics parameters as well as the viscosity of industrial polyurethane formulations (polyol-isocyanate-water mixture) because the...

A key problem in the modeling of polyurethane foaming is the determination of relevant physical parameters for the viscosity, the gas expansion and the curing rate. Indeed, it is difficult to measure the chemical kinetics parameters as well as the viscosity of industrial polyurethane formulations (polyol-isocyanate-water mixture) because ...

International audience

International audience

The laser-induced fluorescence (LIF) thermometry is applied to measure the temperature field surrounding a single vapor bubble growing at an artificial nucleation site. In order to correct measurement errors due to the non-uniformity of the incident laser intensity, the two-color LIF thermometry technique is used in this nucleate boiling...

This paper aims at a better understanding of the polypropylene (PP) physical extrusion foaming process with the objective of obtaining the lowest possible foam density. Two branched PPs were compared to the corresponding linear ones. Their shear and elongation viscosities were measured as well as their crystalline properties. Trials were...

This study aims at a better understanding of the polypropylene (PP) foamability by physical extrusion foaming. Trials were conducted in a single screw extruder equipped with a gear pump for the gas dissolution step (same extrusion parameters, 1wt% CO2) and a static mixer cooler allowing to decrease the melt temperature before the final die...

This study aims to better understand the polypropylene (PP) foamability by physical extrusion foaming comparing branched chains with strain hardening versus linear ones. Trials were conducted in a single screw extrusion equipped with a gear pump for the gas dissolution step (same extrusion parameters, 1wt% CO2) and a static mixer cooler...

International audience

This study aims to better understand the polypropylene (PP) foamability by physical extrusion foaming comparing branched chains with strain hardening versus linear ones. Trials were conducted in a single screw extrusion equipped with a gear pump for the gas dissolution step (same extrusion parameters, 1wt% CO2) and a static mixer cooler...

Fundamental comprehension of bubble growth on a heated surface is primordial to better understand the heat transfer during boiling phenomena. The behaviour of a bubble growing at a heated surface has been extensively studied by many authors using different numerical methods. To validate and complete these simulations, suitable experimental data...

Poly(ethylene 2,5-furandicarboxylate) (PEF) is an emerging biobased thermoplastic polymer that may replace PET for stretching applications such as bottle blowing, thermoforming, or film extrusion. The stretch ability and strain induced microstructure in PEF have not been fully addressed in the literature despite being the key issue for...

International audience

The aim of this work is to assess the potential of graphene nanoplatelets (GNP) according to their production method to improve properties of composites based on polypropylene and elaborated by melt mixing. The effects of GNP size on structural, thermal, rheological and mechanical properties of composites were investigated. Three grades of...