... Influence of the crystalline phase on the mechanical properties of unfilled and CaCO3 filled ... more ... Influence of the crystalline phase on the mechanical properties of unfilled and CaCO3 filled polypropylene . Part I :Structural and mechanical characterization. Thomas Labour 1 , CatherineGauthier 1 , Roland Seguela 1 , Gérard Vigier 1 , Y. Bomal, G. Orange. (2001). ...
A new approach is proposed to analyze small amounts of polymer in a cement paste by means of a dy... more A new approach is proposed to analyze small amounts of polymer in a cement paste by means of a dynamic mechanical thermoanalyser. The polymer-cement ratio is determined from the drop in the storage modulus E′ at the glass transition of the polymer. Different calibration curves are determined by analyzing the viscoelastic behaviour of the polymer in the cement from storage
A small amount of polymer in water solution form (polyvinylpyrolidone or polyvinylalcohol) was ad... more A small amount of polymer in water solution form (polyvinylpyrolidone or polyvinylalcohol) was added to a mix high silicate cement + amorphous silica, with reduced water to cement ratio. It was shown that as the molecular mass of the polymer is increased, the fracture stress and the stored energy at fracture of the specimens improved. The polymer induces an increase
... sintered material (RSMZ) which retains its strength, about 330MPa, up to 1250 C. This materia... more ... sintered material (RSMZ) which retains its strength, about 330MPa, up to 1250 C. This material has been obtained without any additives and so there is no important residual phase along grain boundaries as occurs with ZAM materials processed using MgO as an additive. ...
The fracture toughness of a semi-crystalline polymer (PP) filled with mineral submicron and micro... more The fracture toughness of a semi-crystalline polymer (PP) filled with mineral submicron and micron scale particles is investigated according to the J-integral method: determination of the crack initiation energy (Jc), and the crack propagation resistance dJ/d(Δa). Ultrafine mineral particles as precipitated silica (aggregate particle size 1 μm), lead to an improvement of the PP fracture toughness by induced local bebonding
The fracture toughness of a semi-crystalline polymer (PP) filled with stiff particles (CaCO3) is ... more The fracture toughness of a semi-crystalline polymer (PP) filled with stiff particles (CaCO3) is investigated according to the J-integral method: a brittle to ductile behaviour is observed as a function of particle size and surface treatment, with an increase of dissipated energy. The behaviour of PP/CaCO3 composites with respect to crack initiation, JC, is mainly determined by the matrix, i.e. by the polymeric phase itself which is modified in terms of crystallinity or spherulite size by the dispersed particles. The crack propagation, dJ/d(Δa) slope, is controlled by the ability to develop local deformation along the particle/matrix interface: cavitation development is shown to be the main energy dissipative mechanism in these filled materials. The cavitation process is controlled by the matrix/particle bonding strength which is a function of the size of the particle and the adhesion energy. Mineral particles with controlled size and/or surface chemistry can be used as polymer filler to enhance stiffness but also to develop toughening mechanisms with an increase of dissipative fracture energy.
&sume -Le d u l e elastique et la contrainte B l a rupture sont determines pour quatre nuances : ... more &sume -Le d u l e elastique et la contrainte B l a rupture sont determines pour quatre nuances : W-(6,5 -12 -15 e t 25) % Co jusqu'a 1000°C. La variation du module de W!dIBULL est mesuree en t e e r a t u r e pour la nuance W-ti,5 % Co. Les mesures de thnacite sont rCalisQs jusqu'h 800°C sur t r o i s nuances : WC -(6,5 -1 5 et 25)% Co et la v a l i d i t 6 de ces mesures est
The paper presents an analytical multi-scale approach for the modelling of rough surfaces in rega... more The paper presents an analytical multi-scale approach for the modelling of rough surfaces in regard to rubber friction properties. In addition to a fractal description of the micrometer range within the length-scale interval [5-100 m], the macrotexture is considered via the introduction of a second scaling regime for the contact interval [300-1000 m]. As a result, the hysteresis friction coefficient is decomposed in two distinct contributions. The macrotexture mostly contributes to hysteresis friction, while the microtexture is found to be determining for the amount of contact patches, e.g. the real area of contact. Experimental friction tests carried out for carbon black and silica filled S-SBR 5025 on rough surfaces and road pavement under wet conditions point out the relevance of a two-scaling-ranges approach for the modelling of hysteresis friction. Finally, predictions of the load dependent hysteresis friction coefficient are formulated for rough surfaces and give a deeper insight into the physical mechanisms involved in rubber friction properties.
... Influence of the crystalline phase on the mechanical properties of unfilled and CaCO3 filled ... more ... Influence of the crystalline phase on the mechanical properties of unfilled and CaCO3 filled polypropylene . Part I :Structural and mechanical characterization. Thomas Labour 1 , CatherineGauthier 1 , Roland Seguela 1 , Gérard Vigier 1 , Y. Bomal, G. Orange. (2001). ...
Thermomechanical ceramics have interesting properties: mainly high hardness, high wear resistance... more Thermomechanical ceramics have interesting properties: mainly high hardness, high wear resistance, good chemical resistance, good mechanical strength at high temperatures and generally low thermal conductivity. But, the engineering use of ceramics as structural parts is at the moment limited by their inherent brittleness. The toughness values of ceramics are between about to 5 MPa f i whereas the toughness values of metals are much higher (from 20 to 200 MPa fi). To avoid this brittleness, composite ceramics have to be used. Two types of composite materials can be developed: particle-reinforced composites and fiber-reinforced composites. In this paper, some examples of reinforcement of ceramics are presented. Two cases will be developed: second-phase reinforcement with zirconia particles or other particles, and the composites reinforced by fibers or whiskers.
... Influence of the crystalline phase on the mechanical properties of unfilled and CaCO3 filled ... more ... Influence of the crystalline phase on the mechanical properties of unfilled and CaCO3 filled polypropylene . Part I :Structural and mechanical characterization. Thomas Labour 1 , CatherineGauthier 1 , Roland Seguela 1 , Gérard Vigier 1 , Y. Bomal, G. Orange. (2001). ...
A new approach is proposed to analyze small amounts of polymer in a cement paste by means of a dy... more A new approach is proposed to analyze small amounts of polymer in a cement paste by means of a dynamic mechanical thermoanalyser. The polymer-cement ratio is determined from the drop in the storage modulus E′ at the glass transition of the polymer. Different calibration curves are determined by analyzing the viscoelastic behaviour of the polymer in the cement from storage
A small amount of polymer in water solution form (polyvinylpyrolidone or polyvinylalcohol) was ad... more A small amount of polymer in water solution form (polyvinylpyrolidone or polyvinylalcohol) was added to a mix high silicate cement + amorphous silica, with reduced water to cement ratio. It was shown that as the molecular mass of the polymer is increased, the fracture stress and the stored energy at fracture of the specimens improved. The polymer induces an increase
... sintered material (RSMZ) which retains its strength, about 330MPa, up to 1250 C. This materia... more ... sintered material (RSMZ) which retains its strength, about 330MPa, up to 1250 C. This material has been obtained without any additives and so there is no important residual phase along grain boundaries as occurs with ZAM materials processed using MgO as an additive. ...
The fracture toughness of a semi-crystalline polymer (PP) filled with mineral submicron and micro... more The fracture toughness of a semi-crystalline polymer (PP) filled with mineral submicron and micron scale particles is investigated according to the J-integral method: determination of the crack initiation energy (Jc), and the crack propagation resistance dJ/d(Δa). Ultrafine mineral particles as precipitated silica (aggregate particle size 1 μm), lead to an improvement of the PP fracture toughness by induced local bebonding
The fracture toughness of a semi-crystalline polymer (PP) filled with stiff particles (CaCO3) is ... more The fracture toughness of a semi-crystalline polymer (PP) filled with stiff particles (CaCO3) is investigated according to the J-integral method: a brittle to ductile behaviour is observed as a function of particle size and surface treatment, with an increase of dissipated energy. The behaviour of PP/CaCO3 composites with respect to crack initiation, JC, is mainly determined by the matrix, i.e. by the polymeric phase itself which is modified in terms of crystallinity or spherulite size by the dispersed particles. The crack propagation, dJ/d(Δa) slope, is controlled by the ability to develop local deformation along the particle/matrix interface: cavitation development is shown to be the main energy dissipative mechanism in these filled materials. The cavitation process is controlled by the matrix/particle bonding strength which is a function of the size of the particle and the adhesion energy. Mineral particles with controlled size and/or surface chemistry can be used as polymer filler to enhance stiffness but also to develop toughening mechanisms with an increase of dissipative fracture energy.
&sume -Le d u l e elastique et la contrainte B l a rupture sont determines pour quatre nuances : ... more &sume -Le d u l e elastique et la contrainte B l a rupture sont determines pour quatre nuances : W-(6,5 -12 -15 e t 25) % Co jusqu'a 1000°C. La variation du module de W!dIBULL est mesuree en t e e r a t u r e pour la nuance W-ti,5 % Co. Les mesures de thnacite sont rCalisQs jusqu'h 800°C sur t r o i s nuances : WC -(6,5 -1 5 et 25)% Co et la v a l i d i t 6 de ces mesures est
The paper presents an analytical multi-scale approach for the modelling of rough surfaces in rega... more The paper presents an analytical multi-scale approach for the modelling of rough surfaces in regard to rubber friction properties. In addition to a fractal description of the micrometer range within the length-scale interval [5-100 m], the macrotexture is considered via the introduction of a second scaling regime for the contact interval [300-1000 m]. As a result, the hysteresis friction coefficient is decomposed in two distinct contributions. The macrotexture mostly contributes to hysteresis friction, while the microtexture is found to be determining for the amount of contact patches, e.g. the real area of contact. Experimental friction tests carried out for carbon black and silica filled S-SBR 5025 on rough surfaces and road pavement under wet conditions point out the relevance of a two-scaling-ranges approach for the modelling of hysteresis friction. Finally, predictions of the load dependent hysteresis friction coefficient are formulated for rough surfaces and give a deeper insight into the physical mechanisms involved in rubber friction properties.
... Influence of the crystalline phase on the mechanical properties of unfilled and CaCO3 filled ... more ... Influence of the crystalline phase on the mechanical properties of unfilled and CaCO3 filled polypropylene . Part I :Structural and mechanical characterization. Thomas Labour 1 , CatherineGauthier 1 , Roland Seguela 1 , Gérard Vigier 1 , Y. Bomal, G. Orange. (2001). ...
Thermomechanical ceramics have interesting properties: mainly high hardness, high wear resistance... more Thermomechanical ceramics have interesting properties: mainly high hardness, high wear resistance, good chemical resistance, good mechanical strength at high temperatures and generally low thermal conductivity. But, the engineering use of ceramics as structural parts is at the moment limited by their inherent brittleness. The toughness values of ceramics are between about to 5 MPa f i whereas the toughness values of metals are much higher (from 20 to 200 MPa fi). To avoid this brittleness, composite ceramics have to be used. Two types of composite materials can be developed: particle-reinforced composites and fiber-reinforced composites. In this paper, some examples of reinforcement of ceramics are presented. Two cases will be developed: second-phase reinforcement with zirconia particles or other particles, and the composites reinforced by fibers or whiskers.
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