Maria Luda | Università degli Studi di Torino (original) (raw)

Papers by Maria Luda

Research paper thumbnail of Recycling of EPDM via Continuous Thermo-Mechanical Devulcanization with Co-Rotating Twin-Screw Extruder

Polymers

Devulcanization represents the recycling of choice for a homogenous rubber waste stream because i... more Devulcanization represents the recycling of choice for a homogenous rubber waste stream because it allows revulcanization of samples previously devulcanized, making the life of the rubber virtually endless, according to the principles of circular economy. Among the many devulcanization processes, the thermo-mechanical one is the most appealing because it is a continuous process, easy to be industrialized. In this paper a comprehensive set of analyses (FTIR, TGA, DSC, elemental analyses, Py-GC/MS, swelling tests) were carried out on a post-industrial ethylene propylene diene monomer (EPDM), thermo-mechanical devulcanized in a co-rotating twin-screw extruder with different process parameters (thermal and screw profile, rpm). Results of the swelling test according to the Flory–Rehner theory and Horikx analyses show that the higher the thermal profile and the higher the rpm, the higher is the percentage of devulcanization. The quality of the devulcanized sample in terms of sol fraction ...

Research paper thumbnail of Combustion and fire retardance of poly(2,6-dimethyl-1,4-phenylene ether)-high-impact polystyrene blends. II. Chemical aspects

Journal of Applied Polymer Science, 1998

Research paper thumbnail of Cyclodextrins and Cyclodextrin Derivatives as Green Char Promoters in Flame Retardants Formulations for Polymeric Materials. A Review

Polymers

Polymers are intrinsically flammable materials; hence, fire retardance (FR) is required in their ... more Polymers are intrinsically flammable materials; hence, fire retardance (FR) is required in their most common applications (i.e., electronic and construction, to mention some). Recently, it has been reported that cyclodextrin (CD) and cyclodextrin derivatives are beginning to be introduced into Intumescent Fire Retardant (IFR) formulations in place of pentaerythritol, which is used in IFRs that are currently on the market. Since IFRs are of less environmental concern than their hazardous halogen containing counterparts, the use of natural origin compounds in IFRs provides a way to comply with green chemistry issues. BCD and BCD derivatives presence in IFR mixtures promotes a higher yield of blowing gases and char when polymeric materials undergo combustion. Both processes play important roles in intumescence. The key rule to obtain in insulating compact char is the good dispersion of the nanoparticles in the matrix, which can be achieved by functionalizing nanoparticles with BCD deri...

Research paper thumbnail of Evaluation of Antifingerprint Properties of Plastic Surfaces Used in Automotive Components

International Journal of Polymer Science

The antifingerprint properties of a range of surfaces produced with different technologies (in-mo... more The antifingerprint properties of a range of surfaces produced with different technologies (in-mould decoration, in-mould labeling, and painted) were objectively evaluated by depositing on them in standard conditions an artificial fingerprint for direct determination of its visibility. The artificial fingerprint behaves similarly to the real human fingerprints. A classification method is then proposed to classify surfaces on the base of antifingerprint properties by measuring the roughness profile (Ra) and calculating the % variation of gloss (GU 20 and 60°), haze, luminance (L), and diffuse reflectance (R) values after fingerprint deposition. This approach provides an objective and quantitative test method to determine visual antifingerprint properties of coated surfaces, instead of the “easy-to-clean” properties commonly evaluated. The data acquired provides a design guideline for fabricating visually fingerprint-free surfaces by controlling roughness, texture, color, and transpar...

Research paper thumbnail of Monte Carlo simulations of polymer degradations. 1. Degradations without volatilization

Research paper thumbnail of Monte Carlo simulations of polymer degradations. 1. Degradations without volatilization

Research paper thumbnail of Regenerative Recycling of Automotive Polymer Components: Poly(propylene) Based Car Bumpers

Macromolecular Materials and Engineering, 2003

Research paper thumbnail of PVC and PVC-VAc nanocomposites : Negative effects on thermal stability

Acs Symposium Series, 2006

Research paper thumbnail of Mechanisms of photo-oxidation of polyurethane derivatives

European Coatings Journal, 2000

Research paper thumbnail of Thermal degradation and fire retardancy of antimony and bismuth trihalides-melamine complexes

Polymer Degradation and Stability, 1991

ABSTRACT

Research paper thumbnail of Characterisation of smoke in expanded polystyrene combustion

Polymer Degradation and Stability, 2001

Research paper thumbnail of Effect of filler type and processing apparatus on the properties of the recycled "light fraction" from municipal post consumer plastics

Research paper thumbnail of Post-irradiation oxidation of different polyethylenes

Polymer Degradation and Stability, Apr 1, 2011

Research paper thumbnail of Natural Ageing of Automotive Polymer Components: Characterisation of New and Used Poly(propylene) based Car Bumpers

Macromolecular Materials and Engineering, Jun 1, 2002

Research paper thumbnail of Thermal degradation of polybutadiene. II: Overall thermal behaviour of polymers with different microstructures

Macromolecular Chemistry and Physics, 1992

Research paper thumbnail of Process for Recycling Organic Materials with the Production of Carbon Nanotubes

ABSTRACT A process for the recycling of organic waste materials, particularly waste plastics mate... more ABSTRACT A process for the recycling of organic waste materials, particularly waste plastics materials comprising a stage of pyrolysing the materials and a stage of converting the gaseous pyrolysis products into carbon nanotubes, in which conversion into nanotubes takes place through vapour phase chemical deposition in an inert gas with the help of an organometallic catalyst, particularly ferrocene, is described. The process therefore makes it possible to convert pyrolysis products which also comprise hydrocarbons of a toxic and harmful nature that would otherwise have to be removed in conventional treatments for recycling plastics materials by pyrolysis into a raw material of high value (nanotubes).

Research paper thumbnail of Stabilisation of UHMWPE with Vitamin E

Research paper thumbnail of Oxidation and Stabilization of orthopedic UHMWPE

Research paper thumbnail of The use of thermographic technique in the evaluation of polymers combustion and fire retardants performance

Research paper thumbnail of Characterisation of Used PP-Based Car Bumpers and Their Recycling Properties

ISRN Materials Science, 2013

ABSTRACT Three used PP-based car bumpers are characterized by many techniques (fractionation, IR,... more ABSTRACT Three used PP-based car bumpers are characterized by many techniques (fractionation, IR, TGA, DSC, DMTA, and SEM). They show different impact and static and dynamic mechanical properties depending on their composition and morphology. It appears that block copolymer compatibilizers constituted by polyethylene-polypropylene sequences allow a better compatibility between the rubber domains and the PP matrix leading to relatively high impact resistance. Indeed if the ethylene sequences of the copolymer are large enough to crystallize, the decreased mobility of the whole system impairs the impact resistance. In addition, a higher amount of rubber in domains regular in shape and of greater dimension (1–3 μm) promotes a more homogeneous dispersion of external force inside the material, decreasing the risk of fracture. The amount of mineral fillers regulates the elastic modulus (the higher the load, the higher the modulus); however, a fairly good interfacial adhesion is required for satisfactory impact strength. All PP-based bumpers have been mechanically recycled in an internal mixer to redistribute oxidized species and to reestablish phase compatibilization. Recycling improves mechanical properties in slow speed test but fails to increase impact strength particularly in filled bumper, in which the quality of the matrix/filler interphase is hard to improve by simple remixing.

Research paper thumbnail of Recycling of EPDM via Continuous Thermo-Mechanical Devulcanization with Co-Rotating Twin-Screw Extruder

Polymers

Devulcanization represents the recycling of choice for a homogenous rubber waste stream because i... more Devulcanization represents the recycling of choice for a homogenous rubber waste stream because it allows revulcanization of samples previously devulcanized, making the life of the rubber virtually endless, according to the principles of circular economy. Among the many devulcanization processes, the thermo-mechanical one is the most appealing because it is a continuous process, easy to be industrialized. In this paper a comprehensive set of analyses (FTIR, TGA, DSC, elemental analyses, Py-GC/MS, swelling tests) were carried out on a post-industrial ethylene propylene diene monomer (EPDM), thermo-mechanical devulcanized in a co-rotating twin-screw extruder with different process parameters (thermal and screw profile, rpm). Results of the swelling test according to the Flory–Rehner theory and Horikx analyses show that the higher the thermal profile and the higher the rpm, the higher is the percentage of devulcanization. The quality of the devulcanized sample in terms of sol fraction ...

Research paper thumbnail of Combustion and fire retardance of poly(2,6-dimethyl-1,4-phenylene ether)-high-impact polystyrene blends. II. Chemical aspects

Journal of Applied Polymer Science, 1998

Research paper thumbnail of Cyclodextrins and Cyclodextrin Derivatives as Green Char Promoters in Flame Retardants Formulations for Polymeric Materials. A Review

Polymers

Polymers are intrinsically flammable materials; hence, fire retardance (FR) is required in their ... more Polymers are intrinsically flammable materials; hence, fire retardance (FR) is required in their most common applications (i.e., electronic and construction, to mention some). Recently, it has been reported that cyclodextrin (CD) and cyclodextrin derivatives are beginning to be introduced into Intumescent Fire Retardant (IFR) formulations in place of pentaerythritol, which is used in IFRs that are currently on the market. Since IFRs are of less environmental concern than their hazardous halogen containing counterparts, the use of natural origin compounds in IFRs provides a way to comply with green chemistry issues. BCD and BCD derivatives presence in IFR mixtures promotes a higher yield of blowing gases and char when polymeric materials undergo combustion. Both processes play important roles in intumescence. The key rule to obtain in insulating compact char is the good dispersion of the nanoparticles in the matrix, which can be achieved by functionalizing nanoparticles with BCD deri...

Research paper thumbnail of Evaluation of Antifingerprint Properties of Plastic Surfaces Used in Automotive Components

International Journal of Polymer Science

The antifingerprint properties of a range of surfaces produced with different technologies (in-mo... more The antifingerprint properties of a range of surfaces produced with different technologies (in-mould decoration, in-mould labeling, and painted) were objectively evaluated by depositing on them in standard conditions an artificial fingerprint for direct determination of its visibility. The artificial fingerprint behaves similarly to the real human fingerprints. A classification method is then proposed to classify surfaces on the base of antifingerprint properties by measuring the roughness profile (Ra) and calculating the % variation of gloss (GU 20 and 60°), haze, luminance (L), and diffuse reflectance (R) values after fingerprint deposition. This approach provides an objective and quantitative test method to determine visual antifingerprint properties of coated surfaces, instead of the “easy-to-clean” properties commonly evaluated. The data acquired provides a design guideline for fabricating visually fingerprint-free surfaces by controlling roughness, texture, color, and transpar...

Research paper thumbnail of Monte Carlo simulations of polymer degradations. 1. Degradations without volatilization

Research paper thumbnail of Monte Carlo simulations of polymer degradations. 1. Degradations without volatilization

Research paper thumbnail of Regenerative Recycling of Automotive Polymer Components: Poly(propylene) Based Car Bumpers

Macromolecular Materials and Engineering, 2003

Research paper thumbnail of PVC and PVC-VAc nanocomposites : Negative effects on thermal stability

Acs Symposium Series, 2006

Research paper thumbnail of Mechanisms of photo-oxidation of polyurethane derivatives

European Coatings Journal, 2000

Research paper thumbnail of Thermal degradation and fire retardancy of antimony and bismuth trihalides-melamine complexes

Polymer Degradation and Stability, 1991

ABSTRACT

Research paper thumbnail of Characterisation of smoke in expanded polystyrene combustion

Polymer Degradation and Stability, 2001

Research paper thumbnail of Effect of filler type and processing apparatus on the properties of the recycled "light fraction" from municipal post consumer plastics

Research paper thumbnail of Post-irradiation oxidation of different polyethylenes

Polymer Degradation and Stability, Apr 1, 2011

Research paper thumbnail of Natural Ageing of Automotive Polymer Components: Characterisation of New and Used Poly(propylene) based Car Bumpers

Macromolecular Materials and Engineering, Jun 1, 2002

Research paper thumbnail of Thermal degradation of polybutadiene. II: Overall thermal behaviour of polymers with different microstructures

Macromolecular Chemistry and Physics, 1992

Research paper thumbnail of Process for Recycling Organic Materials with the Production of Carbon Nanotubes

ABSTRACT A process for the recycling of organic waste materials, particularly waste plastics mate... more ABSTRACT A process for the recycling of organic waste materials, particularly waste plastics materials comprising a stage of pyrolysing the materials and a stage of converting the gaseous pyrolysis products into carbon nanotubes, in which conversion into nanotubes takes place through vapour phase chemical deposition in an inert gas with the help of an organometallic catalyst, particularly ferrocene, is described. The process therefore makes it possible to convert pyrolysis products which also comprise hydrocarbons of a toxic and harmful nature that would otherwise have to be removed in conventional treatments for recycling plastics materials by pyrolysis into a raw material of high value (nanotubes).

Research paper thumbnail of Stabilisation of UHMWPE with Vitamin E

Research paper thumbnail of Oxidation and Stabilization of orthopedic UHMWPE

Research paper thumbnail of The use of thermographic technique in the evaluation of polymers combustion and fire retardants performance

Research paper thumbnail of Characterisation of Used PP-Based Car Bumpers and Their Recycling Properties

ISRN Materials Science, 2013

ABSTRACT Three used PP-based car bumpers are characterized by many techniques (fractionation, IR,... more ABSTRACT Three used PP-based car bumpers are characterized by many techniques (fractionation, IR, TGA, DSC, DMTA, and SEM). They show different impact and static and dynamic mechanical properties depending on their composition and morphology. It appears that block copolymer compatibilizers constituted by polyethylene-polypropylene sequences allow a better compatibility between the rubber domains and the PP matrix leading to relatively high impact resistance. Indeed if the ethylene sequences of the copolymer are large enough to crystallize, the decreased mobility of the whole system impairs the impact resistance. In addition, a higher amount of rubber in domains regular in shape and of greater dimension (1–3 μm) promotes a more homogeneous dispersion of external force inside the material, decreasing the risk of fracture. The amount of mineral fillers regulates the elastic modulus (the higher the load, the higher the modulus); however, a fairly good interfacial adhesion is required for satisfactory impact strength. All PP-based bumpers have been mechanically recycled in an internal mixer to redistribute oxidized species and to reestablish phase compatibilization. Recycling improves mechanical properties in slow speed test but fails to increase impact strength particularly in filled bumper, in which the quality of the matrix/filler interphase is hard to improve by simple remixing.