The Experts below are selected from a list of 66 Experts worldwide ranked by ideXlab platform
F. Severini - One of the best experts on this subject based on the ideXlab platform.
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Structure of copolymers of polyacrylic acid grafted on ethylene propylene Elastomers as determined by chemical/physical methods: COPOLYMERS OF POLYACRYLIC ACID
Journal of Polymer Science Part C: Polymer Symposia, 2014Co-Authors: A. Crugnola, M. Pegoraro, F. SeveriniAbstract:The raw product obtained from the emulsion polymerization of acrylic acid and ethylene–propylene copolymer is subjected to extraction to remove the polyacrylic acid homo-polymer and the unreacted ethylene-propylene copolymer. The residue is essentially the grafted copolymer. A determination of the force/temperature coefficient (∂f/∂T)I revealed that this material has the apparent properties of a Vulcanized Elastomer. We sought to single out the nature of the physical and chemical ties that are the cause of this behavior. We found that the material is heterophasic and that the intermolecular bonds are found in the phase constituted of polyacrylic acid; these bonds are of a physical nature (hydrogen bonding) and of a chemical nature. The latter are only present if the molding is carried out at sufficiently high temperatures. Intermolecular bonds have been recognized as resulting from a dehydration of the carboxyls with consequent formation of anhydride, and also from a complicated reaction involving a partial degradation of the polyacrylic acid.
A. Crugnola - One of the best experts on this subject based on the ideXlab platform.
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Structure of copolymers of polyacrylic acid grafted on ethylene propylene Elastomers as determined by chemical/physical methods: COPOLYMERS OF POLYACRYLIC ACID
Journal of Polymer Science Part C: Polymer Symposia, 2014Co-Authors: A. Crugnola, M. Pegoraro, F. SeveriniAbstract:The raw product obtained from the emulsion polymerization of acrylic acid and ethylene–propylene copolymer is subjected to extraction to remove the polyacrylic acid homo-polymer and the unreacted ethylene-propylene copolymer. The residue is essentially the grafted copolymer. A determination of the force/temperature coefficient (∂f/∂T)I revealed that this material has the apparent properties of a Vulcanized Elastomer. We sought to single out the nature of the physical and chemical ties that are the cause of this behavior. We found that the material is heterophasic and that the intermolecular bonds are found in the phase constituted of polyacrylic acid; these bonds are of a physical nature (hydrogen bonding) and of a chemical nature. The latter are only present if the molding is carried out at sufficiently high temperatures. Intermolecular bonds have been recognized as resulting from a dehydration of the carboxyls with consequent formation of anhydride, and also from a complicated reaction involving a partial degradation of the polyacrylic acid.
M. Pegoraro - One of the best experts on this subject based on the ideXlab platform.
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Structure of copolymers of polyacrylic acid grafted on ethylene propylene Elastomers as determined by chemical/physical methods: COPOLYMERS OF POLYACRYLIC ACID
Journal of Polymer Science Part C: Polymer Symposia, 2014Co-Authors: A. Crugnola, M. Pegoraro, F. SeveriniAbstract:The raw product obtained from the emulsion polymerization of acrylic acid and ethylene–propylene copolymer is subjected to extraction to remove the polyacrylic acid homo-polymer and the unreacted ethylene-propylene copolymer. The residue is essentially the grafted copolymer. A determination of the force/temperature coefficient (∂f/∂T)I revealed that this material has the apparent properties of a Vulcanized Elastomer. We sought to single out the nature of the physical and chemical ties that are the cause of this behavior. We found that the material is heterophasic and that the intermolecular bonds are found in the phase constituted of polyacrylic acid; these bonds are of a physical nature (hydrogen bonding) and of a chemical nature. The latter are only present if the molding is carried out at sufficiently high temperatures. Intermolecular bonds have been recognized as resulting from a dehydration of the carboxyls with consequent formation of anhydride, and also from a complicated reaction involving a partial degradation of the polyacrylic acid.
Johan J. Sánchez - One of the best experts on this subject based on the ideXlab platform.
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Hard/soft combinations based on thermoplastic Elastomer and a rigid thermoplastic polymer: Study of the adhesion strength
High-Performance Elastomeric Materials Reinforced by Nano-Carbons, 2020Co-Authors: María V. Candal, Orlando O. Santana, Johan J. Sánchez, Graciela Terife, Antonio GordilloAbstract:Abstract The objective of this work was to compare different test methods for determining the adhesion strength between a two overmolding materials: thermoplastic Vulcanized Elastomer (TPV) and a polypropylene (PP). The TPV/PP system was overmolded using different melt temperatures. Three testing methods were studied: Tensile test, Peeling test, and Essential Work of Interfacial Fracture (EWIF) at three different geometries: Single (SENT), Double (DENT) and Center (CNT) Notched Tension. Results showed that the Peeling testing was not an appropriate method to determine adhesion strength of overmolded specimens; at high melt temperatures, the fracture does not occur through the interphase but rather through the TPV. The CNT and DENT geometries showed very high data dispersion, caused by asymmetric crack propagation. The adhesion strength measurement can satisfactorily be done using EWIF-SENT or Tensile testing; however, only the former guarantees that the fracture takes place along the interphase.
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Study of the adhesion strength on overmoulded plastic materials using the essential work of interfacial fracture (EWIF) concept
Journal of Materials Science, 2008Co-Authors: María V. Candal, Orlando O. Santana, Antonio Gordillo, Johan J. SánchezAbstract:The influence of the overmoulding processing conditions (melt and mould temperatures, holding pressure and injection rate) on the adhesion strength between two polymers in a hard–soft part was studied. The used materials were thermoplastic Vulcanized Elastomer (TPV) and polypropylene (PP). The study of the adhesion strength was made by measuring the essential work of interfacial fracture (EWIF) concept using a single edge-notched tension (SENT) geometry. It was observed that, the data distribution was good since an adequate correlation between the total work of interfacial fracture and the ligament length was obtained. It was verified that, when the melt temperature, and in some cases, the mould temperature are increased, a higher adhesion strength is obtained. These parameters affect in higher degree the adhesion strength, since they may improve the interdiffusion and the wetting process of the PP substrate by the molten material (TPV), causing as a result a good contact between them. A little influence was observed in the case of the holding pressure and injection rate.
María V. Candal - One of the best experts on this subject based on the ideXlab platform.
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Hard/soft combinations based on thermoplastic Elastomer and a rigid thermoplastic polymer: Study of the adhesion strength
High-Performance Elastomeric Materials Reinforced by Nano-Carbons, 2020Co-Authors: María V. Candal, Orlando O. Santana, Johan J. Sánchez, Graciela Terife, Antonio GordilloAbstract:Abstract The objective of this work was to compare different test methods for determining the adhesion strength between a two overmolding materials: thermoplastic Vulcanized Elastomer (TPV) and a polypropylene (PP). The TPV/PP system was overmolded using different melt temperatures. Three testing methods were studied: Tensile test, Peeling test, and Essential Work of Interfacial Fracture (EWIF) at three different geometries: Single (SENT), Double (DENT) and Center (CNT) Notched Tension. Results showed that the Peeling testing was not an appropriate method to determine adhesion strength of overmolded specimens; at high melt temperatures, the fracture does not occur through the interphase but rather through the TPV. The CNT and DENT geometries showed very high data dispersion, caused by asymmetric crack propagation. The adhesion strength measurement can satisfactorily be done using EWIF-SENT or Tensile testing; however, only the former guarantees that the fracture takes place along the interphase.
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Study of the adhesion strength on overmoulded plastic materials using the essential work of interfacial fracture (EWIF) concept
Journal of Materials Science, 2008Co-Authors: María V. Candal, Orlando O. Santana, Antonio Gordillo, Johan J. SánchezAbstract:The influence of the overmoulding processing conditions (melt and mould temperatures, holding pressure and injection rate) on the adhesion strength between two polymers in a hard–soft part was studied. The used materials were thermoplastic Vulcanized Elastomer (TPV) and polypropylene (PP). The study of the adhesion strength was made by measuring the essential work of interfacial fracture (EWIF) concept using a single edge-notched tension (SENT) geometry. It was observed that, the data distribution was good since an adequate correlation between the total work of interfacial fracture and the ligament length was obtained. It was verified that, when the melt temperature, and in some cases, the mould temperature are increased, a higher adhesion strength is obtained. These parameters affect in higher degree the adhesion strength, since they may improve the interdiffusion and the wetting process of the PP substrate by the molten material (TPV), causing as a result a good contact between them. A little influence was observed in the case of the holding pressure and injection rate.
