PATRICK DANG - Academia.edu (original) (raw)

Papers by PATRICK DANG

Polymers, Nov 21, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Polymer, 1999

This paper will discuss the nature of the gas induced damage in a poly(vinylidene fluoride) (PVDF... more This paper will discuss the nature of the gas induced damage in a poly(vinylidene fluoride) (PVDF) exposed to `explosive' or rapid pneumatic decompression in a carbon dioxide environment. Generally, under high pressure, the polymer absorbs significant amounts of gas. The large quantity of gas absorbed may induce a dilatation of the specimen and also influence the mechanical properties of the polymer. When the ambient pressure is reduced, the polymer will often suffer irreversible mechanical damage; this process is usually termed explosure decompression failure or `XDF'. This paper is presented in four parts. The first part will describe the variation of the mass of the PVDF polymeric sample in a carbon dioxide medium during the compression and the decompression process at 80°C in the pressure range of 0.1–30MPa. It is shown that the mass of the specimen increases as the pressure increases but, upon decompression under the conditions described, it is quite constant until 15MPa and then it falls rapidly. The second part describes the corresponding volumetric change of the polymer, in situ, during the compression and the decompression at 80°C. The decompression curve exhibits a dilatation peak centred at around 14MPa. The decrease of the mass and the size of the sample is related to the generation of cracks in the polymer matrix during decompression. The third part will describe the results of a mechanical deformation experiment on samples exposed to compression–decompression cycles which is used to establish a relationship between the loss of mechanical properties of the sample and the loss of internal coherence due to the presence of internal cracks. A final part summarises the major conclusions which indicate conclusively that the polymer is irreversibly damaged in the decompression process adopted in the current study.

Journal of Materials Science

ABSTRACT

Journal of Polymer Science Part B: Polymer Physics, 1998

The article reports on the behaviour of poly(vinylidene fluoride) in carbon dioxide at 42°C and 8... more The article reports on the behaviour of poly(vinylidene fluoride) in carbon dioxide at 42°C and 80°C and in a pressure range of 0.1-30 MPa. Experimental techniques for the measurement of gas mass uptake and polymer dilatation are described and the corresponding data are reported as mass sorption and dilatation isotherms, respectively. The mass uptake experiment was also used to follow the evolution of the coefficient of diffusion of carbon dioxide into the polymer as a function of pressure or concentration. An analysis for the calculation of the partial molar volume of carbon dioxide as a function of pressure is also given, which shows that the 'apparent' partial molar volume of the carbon dioxide decreases with pressure to very low values, at high pressure. The computed values are significantly less than those for either the liquid or the solid phases of pure carbon dioxide, and also lower than some data previously reported for silicone elastomers. A consideration of the origins of this apparent anomaly is given in the conclusions.

Polymers

The transportation sector is striving to meet the more severe European legislation which encourag... more The transportation sector is striving to meet the more severe European legislation which encourages all industrial fields to embrace more eco-friendly policies by exploiting constituents from renewable resources. In this framework, the present work assessed the potential of a bio-based, low molecular weight PA11 matrix reinforced with flax and intraply flax/basalt hybrid fabrics. To this aim, both quasi-static and impact performance were addressed through three-point bending and low-velocity impact tests, respectively. For hybrid composites, the effect of stacking sequence, i.e., [0/0] and [0/90], and fiber orientation were considered, while the effect of temperature, i.e., −40 °C, room temperature and +45 °C, was investigated for laminates’ impact response. The mechanical experimental campaign was supported by thermal and morphological analyses. The results disclosed an improved processability of the low molecular weight PA11, which ensured a manufacturing temperature of 200 °C, wh...

Polymer, Sep 1, 2000

PolyVinylidene Fluoride (PVDF) is a polar crystalline polymer commonly found in the apolar a crys... more PolyVinylidene Fluoride (PVDF) is a polar crystalline polymer commonly found in the apolar a crystalline form studied here. The complementarity of a macroscopic (tensile tests at constant crosshead speed) and a microscopic approach (Small-Angle X-ray Scattering and Wide-Angle X-ray Scattering) specifies the cavitation phenomenon occurring in this material when strained. At room temperature, microvoids nucleate predominantly in equatorial intraspherulitic amorphous layers, just before the yield. For further strains, these defects grow in the tensile direction and damage affects a larger area of spherulites. This process, combined with classical amorphous shear mechanisms, prevails in PVDF deformation as crystallite fragmentation remains of minor importance, for axial strains of up to 30%.

The present invention relates to the use of at least one catalyst, at least one thermal stabilize... more The present invention relates to the use of at least one catalyst, at least one thermal stabilizer to copper and at least one oligo- or polycarbodiimide with a matrix comprising at least one thermoplastic polymer, especially a polyamide, to form a composition having good viscosity in the molten state and stable to processing, especially extrusion.

L'invention se rapporte a l'utilisation d'une composition comprenant de 70 a 91 % en ... more L'invention se rapporte a l'utilisation d'une composition comprenant de 70 a 91 % en poids, d'au moins un polyamide semi-cristallin, de 5 a 25 % en poids d'une polyolefine comprenant une fonction epoxy, anhydride ou acide, introduite par greffage ou par copolymerisation, et de 4 a 20 % en poids d'un plastifiant, pour la fabrication de tuyaux flexibles utilises dans l'exploitation des gisements de petrole ou de gaz sous la mer. L'invention se rapporte egalement a un tuyau flexible destine a etre utilise pour l'exploitation des gisements de petrole ou de gaz sous la mer comprenant au moins une couche obtenue a partir d'une telle composition.

Utilizacion de canalizaciones, constituidas, o bien ya sea por una capa interior de PO, de una fo... more Utilizacion de canalizaciones, constituidas, o bien ya sea por una capa interior de PO, de una forma preferente, PE, y por una capa exterior de PA, o de una mezcla de PA y PO de matriz PA, o bien ya sea por una capa exterior de PO, de una forma preferente de PE, y que comprenden una capa interior en PA o en mezcla de PA y PO de matriz PA, o bien ya sea, sucesivamente por una capa interior en PA o en una mezcla de PA y PO de matriz PA, de una capa de PO y de una capa exterior en PA o en mezcla de PA y PO, de matriz PA, para constituir redes de distribucion y/o de transporte de gases combustibles de media y/o de baja presion.

La presente invention concerne l'utilisation d'au moins un catalyseur, d'au moins un ... more La presente invention concerne l'utilisation d'au moins un catalyseur, d'au moins un stabilisant thermique au cuivre et d'au moins un oligo- ou poly-carbodiimide avec une matrice comprenant au moins un polyamide, pour constituer une composition presentant une bonne viscosite a l'etat fondu et stable a la transformation, en particulier a l'extrusion.

La presente invention concerne des canalisations pour le transport et/ou la distribution de gaz c... more La presente invention concerne des canalisations pour le transport et/ou la distribution de gaz combustibles, de gaz liquefies comprenant une couche de polyethylene et une couche interieure et/ou exterieure de polyamide. Ces canalisations peuvent etre avantageusement raccordees par des manchons colles et constituer ainsi les reseaux de distribution ou de transport de gaz de moyenne et basse pressions ou bien elles peuvent etre installees a l'interieur de canalisations metalliques deja existantes. Ces canalisations peuvent etre fabriquees par coextrusion.

La presente invention concerne l'utilisation d'une composition comprenant au moins un pol... more La presente invention concerne l'utilisation d'une composition comprenant au moins un polyamide, dont l'un au moins est un copolyamide semi-cristallin comprenant au moins un motif minoritaire issu de la polycondensation : d'au moins une diamine avec au moins un acide gras polymerise, en particulier un dimere d'acide gras, ou d'au moins un dimere diamine avec au moins un acide dicarboxylique, ou d'au moins un dimere aminoacide, ou leur melanges, comme couche d'etancheite dans un tuyau contenant du petrole ou du gaz, ce tuyau etant utilise dans l'exploitation des gisements de petrole ou de gaz sous la mer (offshore).

Polymers, Nov 21, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Polymer, 1999

This paper will discuss the nature of the gas induced damage in a poly(vinylidene fluoride) (PVDF... more This paper will discuss the nature of the gas induced damage in a poly(vinylidene fluoride) (PVDF) exposed to `explosive' or rapid pneumatic decompression in a carbon dioxide environment. Generally, under high pressure, the polymer absorbs significant amounts of gas. The large quantity of gas absorbed may induce a dilatation of the specimen and also influence the mechanical properties of the polymer. When the ambient pressure is reduced, the polymer will often suffer irreversible mechanical damage; this process is usually termed explosure decompression failure or `XDF'. This paper is presented in four parts. The first part will describe the variation of the mass of the PVDF polymeric sample in a carbon dioxide medium during the compression and the decompression process at 80°C in the pressure range of 0.1–30MPa. It is shown that the mass of the specimen increases as the pressure increases but, upon decompression under the conditions described, it is quite constant until 15MPa and then it falls rapidly. The second part describes the corresponding volumetric change of the polymer, in situ, during the compression and the decompression at 80°C. The decompression curve exhibits a dilatation peak centred at around 14MPa. The decrease of the mass and the size of the sample is related to the generation of cracks in the polymer matrix during decompression. The third part will describe the results of a mechanical deformation experiment on samples exposed to compression–decompression cycles which is used to establish a relationship between the loss of mechanical properties of the sample and the loss of internal coherence due to the presence of internal cracks. A final part summarises the major conclusions which indicate conclusively that the polymer is irreversibly damaged in the decompression process adopted in the current study.

Journal of Materials Science

ABSTRACT

Journal of Polymer Science Part B: Polymer Physics, 1998

The article reports on the behaviour of poly(vinylidene fluoride) in carbon dioxide at 42°C and 8... more The article reports on the behaviour of poly(vinylidene fluoride) in carbon dioxide at 42°C and 80°C and in a pressure range of 0.1-30 MPa. Experimental techniques for the measurement of gas mass uptake and polymer dilatation are described and the corresponding data are reported as mass sorption and dilatation isotherms, respectively. The mass uptake experiment was also used to follow the evolution of the coefficient of diffusion of carbon dioxide into the polymer as a function of pressure or concentration. An analysis for the calculation of the partial molar volume of carbon dioxide as a function of pressure is also given, which shows that the 'apparent' partial molar volume of the carbon dioxide decreases with pressure to very low values, at high pressure. The computed values are significantly less than those for either the liquid or the solid phases of pure carbon dioxide, and also lower than some data previously reported for silicone elastomers. A consideration of the origins of this apparent anomaly is given in the conclusions.

Polymers

The transportation sector is striving to meet the more severe European legislation which encourag... more The transportation sector is striving to meet the more severe European legislation which encourages all industrial fields to embrace more eco-friendly policies by exploiting constituents from renewable resources. In this framework, the present work assessed the potential of a bio-based, low molecular weight PA11 matrix reinforced with flax and intraply flax/basalt hybrid fabrics. To this aim, both quasi-static and impact performance were addressed through three-point bending and low-velocity impact tests, respectively. For hybrid composites, the effect of stacking sequence, i.e., [0/0] and [0/90], and fiber orientation were considered, while the effect of temperature, i.e., −40 °C, room temperature and +45 °C, was investigated for laminates’ impact response. The mechanical experimental campaign was supported by thermal and morphological analyses. The results disclosed an improved processability of the low molecular weight PA11, which ensured a manufacturing temperature of 200 °C, wh...

Polymer, Sep 1, 2000

PolyVinylidene Fluoride (PVDF) is a polar crystalline polymer commonly found in the apolar a crys... more PolyVinylidene Fluoride (PVDF) is a polar crystalline polymer commonly found in the apolar a crystalline form studied here. The complementarity of a macroscopic (tensile tests at constant crosshead speed) and a microscopic approach (Small-Angle X-ray Scattering and Wide-Angle X-ray Scattering) specifies the cavitation phenomenon occurring in this material when strained. At room temperature, microvoids nucleate predominantly in equatorial intraspherulitic amorphous layers, just before the yield. For further strains, these defects grow in the tensile direction and damage affects a larger area of spherulites. This process, combined with classical amorphous shear mechanisms, prevails in PVDF deformation as crystallite fragmentation remains of minor importance, for axial strains of up to 30%.

The present invention relates to the use of at least one catalyst, at least one thermal stabilize... more The present invention relates to the use of at least one catalyst, at least one thermal stabilizer to copper and at least one oligo- or polycarbodiimide with a matrix comprising at least one thermoplastic polymer, especially a polyamide, to form a composition having good viscosity in the molten state and stable to processing, especially extrusion.

L'invention se rapporte a l'utilisation d'une composition comprenant de 70 a 91 % en ... more L'invention se rapporte a l'utilisation d'une composition comprenant de 70 a 91 % en poids, d'au moins un polyamide semi-cristallin, de 5 a 25 % en poids d'une polyolefine comprenant une fonction epoxy, anhydride ou acide, introduite par greffage ou par copolymerisation, et de 4 a 20 % en poids d'un plastifiant, pour la fabrication de tuyaux flexibles utilises dans l'exploitation des gisements de petrole ou de gaz sous la mer. L'invention se rapporte egalement a un tuyau flexible destine a etre utilise pour l'exploitation des gisements de petrole ou de gaz sous la mer comprenant au moins une couche obtenue a partir d'une telle composition.

Utilizacion de canalizaciones, constituidas, o bien ya sea por una capa interior de PO, de una fo... more Utilizacion de canalizaciones, constituidas, o bien ya sea por una capa interior de PO, de una forma preferente, PE, y por una capa exterior de PA, o de una mezcla de PA y PO de matriz PA, o bien ya sea por una capa exterior de PO, de una forma preferente de PE, y que comprenden una capa interior en PA o en mezcla de PA y PO de matriz PA, o bien ya sea, sucesivamente por una capa interior en PA o en una mezcla de PA y PO de matriz PA, de una capa de PO y de una capa exterior en PA o en mezcla de PA y PO, de matriz PA, para constituir redes de distribucion y/o de transporte de gases combustibles de media y/o de baja presion.

La presente invention concerne l'utilisation d'au moins un catalyseur, d'au moins un ... more La presente invention concerne l'utilisation d'au moins un catalyseur, d'au moins un stabilisant thermique au cuivre et d'au moins un oligo- ou poly-carbodiimide avec une matrice comprenant au moins un polyamide, pour constituer une composition presentant une bonne viscosite a l'etat fondu et stable a la transformation, en particulier a l'extrusion.

La presente invention concerne des canalisations pour le transport et/ou la distribution de gaz c... more La presente invention concerne des canalisations pour le transport et/ou la distribution de gaz combustibles, de gaz liquefies comprenant une couche de polyethylene et une couche interieure et/ou exterieure de polyamide. Ces canalisations peuvent etre avantageusement raccordees par des manchons colles et constituer ainsi les reseaux de distribution ou de transport de gaz de moyenne et basse pressions ou bien elles peuvent etre installees a l'interieur de canalisations metalliques deja existantes. Ces canalisations peuvent etre fabriquees par coextrusion.

La presente invention concerne l'utilisation d'une composition comprenant au moins un pol... more La presente invention concerne l'utilisation d'une composition comprenant au moins un polyamide, dont l'un au moins est un copolyamide semi-cristallin comprenant au moins un motif minoritaire issu de la polycondensation : d'au moins une diamine avec au moins un acide gras polymerise, en particulier un dimere d'acide gras, ou d'au moins un dimere diamine avec au moins un acide dicarboxylique, ou d'au moins un dimere aminoacide, ou leur melanges, comme couche d'etancheite dans un tuyau contenant du petrole ou du gaz, ce tuyau etant utilise dans l'exploitation des gisements de petrole ou de gaz sous la mer (offshore).