cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14321806.v1
title: Reuse of waste printed circuit boards as fillers in polypropylene composites

description: ABSTRACT Printed Circuit Boards (PCBs) are the most valuable parts of e-waste because they have a considerable amount of metals with recovery potential. Recycling processes aimed at recovering metals from PCBs have aroused great interest recently. However, there is a fraction of this waste that is not utilized and has uncertain destination, e.g. the non-metallic fraction and the dust generated during metal recovery processes. The focus of this study was to employ the powder generated in the mechanical comminution, granulometric, magnetic and electrostatic separation processes of controller and temperature indicator PCBs of cold rooms to obtain polypropylene (PP) matrix composites with distinct PCBs powder content, 5, 10 and 20% in weight. The sample was collected during the mechanical comminution processes. The materials were weighed, mixed, injection molded and later characterized using tensile tests, Shore D hardness, infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. Results of the tensile and hardness tests showed properties slightly superior to pure PP, except for strain at break, which was reduced up to 2.7 times for the sample with 20% of residue. In all, the development of composites using the powder of PCBs was considered feasible for applications where tensile strength, stiffness and hardness are important, even for a large amount of residue added (20%).
DOI: 10.6084/m9.figshare.14321806
title: Reuse of waste printed circuit boards as fillers in polypropylene composites

description: ABSTRACT Printed Circuit Boards (PCBs) are the most valuable parts of e-waste because they have a considerable amount of metals with recovery potential. Recycling processes aimed at recovering metals from PCBs have aroused great interest recently. However, there is a fraction of this waste that is not utilized and has uncertain destination, e.g. the non-metallic fraction and the dust generated during metal recovery processes. The focus of this study was to employ the powder generated in the mechanical comminution, granulometric, magnetic and electrostatic separation processes of controller and temperature indicator PCBs of cold rooms to obtain polypropylene (PP) matrix composites with distinct PCBs powder content, 5, 10 and 20% in weight. The sample was collected during the mechanical comminution processes. The materials were weighed, mixed, injection molded and later characterized using tensile tests, Shore D hardness, infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. Results of the tensile and hardness tests showed properties slightly superior to pure PP, except for strain at break, which was reduced up to 2.7 times for the sample with 20% of residue. In all, the development of composites using the powder of PCBs was considered feasible for applications where tensile strength, stiffness and hardness are important, even for a large amount of residue added (20%).
DOI: 10.6084/m9.figshare.14321808.v1
title: Determination and analysis of fracture toughness on fiber-metal laminates composite materials

description: ABSTRACT The determination of fracture toughness in hybrid composite materials, fiber-metal laminates(FML) is very important in order to make a structural integrity analysis that allows estimating damage tolerance and the remaining strength of the material against crack propagation. This evaluation should be carried out in both aeronautical and naval structures that use FML composites, CARALL type (CArbon Reinforced Aluminum Laminates). This paper presents the experimental determination of fracture toughness in terms of parameters J and CTOD using compact C (T) specimens in two types of composite material laminated with 6061-T0 aluminum sheets in one case and sheets 1050 aluminum in another and carbon fibers NCT-301, embedded in epoxy resin, for both materials. The results indicate that the use of the elasto-plastic fracture toughness test techniques, applying ASTM E1820, are acceptable for the determination of the fracture toughness J in CARALL type materials. Such characterization is necessary for the development of a tolerable damage assessment program both at the design level and for a defect significance analysis based on the results of non-destructive tests on this type of composite materials.
DOI: 10.6084/m9.figshare.14321808
title: Determination and analysis of fracture toughness on fiber-metal laminates composite materials

description: ABSTRACT The determination of fracture toughness in hybrid composite materials, fiber-metal laminates(FML) is very important in order to make a structural integrity analysis that allows estimating damage tolerance and the remaining strength of the material against crack propagation. This evaluation should be carried out in both aeronautical and naval structures that use FML composites, CARALL type (CArbon Reinforced Aluminum Laminates). This paper presents the experimental determination of fracture toughness in terms of parameters J and CTOD using compact C (T) specimens in two types of composite material laminated with 6061-T0 aluminum sheets in one case and sheets 1050 aluminum in another and carbon fibers NCT-301, embedded in epoxy resin, for both materials. The results indicate that the use of the elasto-plastic fracture toughness test techniques, applying ASTM E1820, are acceptable for the determination of the fracture toughness J in CARALL type materials. Such characterization is necessary for the development of a tolerable damage assessment program both at the design level and for a defect significance analysis based on the results of non-destructive tests on this type of composite materials.
DOI: 10.6084/m9.figshare.14321809
title: Analysis of epoxy based paint efficiency in expanded clay lightweight concrete protection of sulfuric acid attack

description: ABSTRACT The purpose of this study is to analyze the efficiency of epoxydic base paint used as a protective coating on expanded clay lightweight concrete under sulfuric acid (H2SO4) attack. External attacks can promote expansions and accelerated degradation, reducing the concrete durability. Developed protections, such as paints have an important performance result, because they have good adhesion to the concrete surface, weathering and photodegradation resistant, besides provide a good chemical stability. The performance of epoxydic paint was assessed through visual inspection, compressive strength test, water absorption and mass losses before and after chemical attack. The visual inspection demonstrated that the epoxy-coated lightweight concrete specimens had a clear reduction in the loss of cohesion of the paste caused by the attack. The teste results of regarding water absorption, mass loss and mechanical strength showed the good performance of the epoxydic base paint, preventing the penetration of the aggressive agent on protected concretes. This research shows that epoxydic protection reduces the impact of external acid attacks on concrete and can improve the durability of expanded clay lightweight concrete structures.
DOI: 10.6084/m9.figshare.14321821
title: Comparative analysis of depositions of graphene oxide films by ultrasonic and conventional spray

description: ABSTRACT The spray technique for thin film deposition stands out for its versatility, simplicity and efficiency. In this work, two different spray techniques, conventional and ultrasonic, were used for the production of graphene oxide films, the first one was an industrial equipment for ultrasonic spray production and the second, an adaptation performed with an airbrush, a solenoid, a circuit electric and a program in C ++ language, called conventional spray. The films obtained were characterized with respect to thickness, electrical resistivity, transmittance and morphology. The samples produced by the conventional method presented thicknesses and transmittances more suitable for electronic applications, since the smaller sheet resistances were obtained by the ultrasonic spray method. The morphology of the films shows a better uniformity for the samples obtained by means of the ultrasonic spray technique. The comparative analysis of the results indicated that the conventional spray equipment, although much simpler and low cost, was able to achieve results as satisfactory as those obtained in an industrial ultrasonic spray equipment. The great advantage of the industrial equipment is the possibility of producing several samples simultaneously, while the conventional spray adapted has the benefit of speed, deposition possibility with larger graphene oxide sheets and accessibility of the production and operation of the system.
DOI: 10.6084/m9.figshare.14321821.v1
title: Comparative analysis of depositions of graphene oxide films by ultrasonic and conventional spray

description: ABSTRACT The spray technique for thin film deposition stands out for its versatility, simplicity and efficiency. In this work, two different spray techniques, conventional and ultrasonic, were used for the production of graphene oxide films, the first one was an industrial equipment for ultrasonic spray production and the second, an adaptation performed with an airbrush, a solenoid, a circuit electric and a program in C ++ language, called conventional spray. The films obtained were characterized with respect to thickness, electrical resistivity, transmittance and morphology. The samples produced by the conventional method presented thicknesses and transmittances more suitable for electronic applications, since the smaller sheet resistances were obtained by the ultrasonic spray method. The morphology of the films shows a better uniformity for the samples obtained by means of the ultrasonic spray technique. The comparative analysis of the results indicated that the conventional spray equipment, although much simpler and low cost, was able to achieve results as satisfactory as those obtained in an industrial ultrasonic spray equipment. The great advantage of the industrial equipment is the possibility of producing several samples simultaneously, while the conventional spray adapted has the benefit of speed, deposition possibility with larger graphene oxide sheets and accessibility of the production and operation of the system.
DOI: 10.6084/m9.figshare.14321823
title: Evaluation of the physical, chemical and mechanical properties of starch/PVA/bentonite clay films modified with glycidyl methacrylate

description: ABSTRACT Films constituted by cassava starch, polyvinyl alcohol (PVA) and Bentonite clay (BNT) and glycerol as plasticizer were obtained using the casting method. In order to increase the compatibility of the polymers with the mineral and its hydrophobicity, they were subsequently chemically modified by replacing the hydroxyl groups with vinyls using glycidyl methacrylate (GMA). This procedure generated films with excellent water sorption stability and 15% lower water vapor permeability. This strategy also resulted in a 25% improvement in tensile strength, maintaining the same Young’s modulus and slight decrease in thermal stability (onset of degradation 14 ° C lower). The addition of BNT clay generates composite films with different mechanical, thermal and physical properties, however, there is a dependence between the amount of reinforcement and the structural distribution of the clay lamellae in the matrix. The chemical modifications were confirmed by H 1 NMR, FTIR, XRD and the films were characterized by XRD, sorption and water permeability, mechanical tests (traction, stretching and Young’s modulus) and TGA. The use of 1% w / w of this reinforcement generates composites with structurally exfoliated BNT, independently of the previous modification with glycidyl methacrylate. The formulation with 5% m / m generated intercalated composite films. Any other reinforcing content exhibits agglomerated (packaged) lamellar structures. It is noteworthy that in the formulations reinforced with 1% clay, there was an improvement of about 30% in tensile strength with 60% lower water permeability, for higher clayey loads. These facts indicate that the modifications proposed in this work have generated promising properties for the production of biodegradable packaging materials.
DOI: 10.6084/m9.figshare.14321823.v1
title: Evaluation of the physical, chemical and mechanical properties of starch/PVA/bentonite clay films modified with glycidyl methacrylate

description: ABSTRACT Films constituted by cassava starch, polyvinyl alcohol (PVA) and Bentonite clay (BNT) and glycerol as plasticizer were obtained using the casting method. In order to increase the compatibility of the polymers with the mineral and its hydrophobicity, they were subsequently chemically modified by replacing the hydroxyl groups with vinyls using glycidyl methacrylate (GMA). This procedure generated films with excellent water sorption stability and 15% lower water vapor permeability. This strategy also resulted in a 25% improvement in tensile strength, maintaining the same Young’s modulus and slight decrease in thermal stability (onset of degradation 14 ° C lower). The addition of BNT clay generates composite films with different mechanical, thermal and physical properties, however, there is a dependence between the amount of reinforcement and the structural distribution of the clay lamellae in the matrix. The chemical modifications were confirmed by H 1 NMR, FTIR, XRD and the films were characterized by XRD, sorption and water permeability, mechanical tests (traction, stretching and Young’s modulus) and TGA. The use of 1% w / w of this reinforcement generates composites with structurally exfoliated BNT, independently of the previous modification with glycidyl methacrylate. The formulation with 5% m / m generated intercalated composite films. Any other reinforcing content exhibits agglomerated (packaged) lamellar structures. It is noteworthy that in the formulations reinforced with 1% clay, there was an improvement of about 30% in tensile strength with 60% lower water permeability, for higher clayey loads. These facts indicate that the modifications proposed in this work have generated promising properties for the production of biodegradable packaging materials.
DOI: 10.6084/m9.figshare.14321827.v1
title: Production and characterization of chitosan spheres/ Dysphania ambrosioides (L.) Mosyakin & Clemants

description: ABSTRACT The objective was to produce and characterize a biomaterial in the form of chitosan spheres/ Dysphania ambrosioides (L.) Mosyakin & Clemants (mastruz) in order to associate positive characteristics of both materials, chitosan with osteoinductive potential and the bone regeneration ability of mastruz, producing a biomaterial to use as bone former and regenarator. Plant specimens were collected, identified botanically and crude alcohol extract (CAE) were obtained. For the production of the chitosan and chitosan spheres with CAE, the Ionotrope Gellification technique was used. The spheres were divided into three groups: one example group of pure chitosan; a second example group with low CAE concentration and a third example group with a higher CAE concentration; and them characterized by Optical Microscopy (OM), Scanning Electron Microscopy (SEM) and swelling degree (SD). OM showed on the external and internal surfaces, spheres with defined limits and with color changed as the percentage of CAE was increased, becoming darker. The SEM showed, in spheres with higher CAE concentration, in comparison with the ones with low CAE concentration: A decrease in size, increase in the quantity and intercommunication of the pores, and the alteration of the geometric shape of both the spheres and their pores. In the analysis of the swelling degree, there were no significant differences between the groups. It is possible to produce chitosan spheres / Dysphania ambrosioides (L.) Mosyakin & Clemants (mastruz) which in the group with the highest percentage of CAE the samples were darker and with higher amounts and intercommunication pores and that although there was swelling, no significant difference was observed between the groups.
DOI: 10.6084/m9.figshare.14321829
title: Fungal biocomposites development from industrial waste

description: ABSTRACT The food manufacturing generates a large amount of organic waste. A flavor industry, for example, can generate annually 104 and 92 tonnes of mate and guarana residues, respectively. An alternative to the reuse of this lignocellulosic material would be to use them in the production of biocomposites with fungal mycelium acting as a binder of the substrate particles. Therefore, the objective of this work was to produce fungal biocomposites of Pleurotus sajor-caju using the mate and guarana residues in a ratio of (1:1) (w/w), checking the influence of the 10, 20 and 30% inoculum fraction and the drying temperature of 40°C and 60°C. For each condition tested, mycelial growth time, initial moisture content, initial drying rate, compressive strength, air moisture absorption and water uptake were evaluated. The condition determined to produce the biocomposites was 10% of inoculum and drying at 60°C, as it presented higher resistance to compression (0.094 MPa), lower absorption of water (91%), higher drying rate (27.7 g/day). The biocomposites utilise biological growth rather than expensive energy intensive manufacturing processes and require only low-cost organic waste as feedstock, can grow to fill complex geometries presented potential for packaging, as they are safe materials that have good compressive strength and low water absorption.
DOI: 10.6084/m9.figshare.14321829.v1
title: Fungal biocomposites development from industrial waste

description: ABSTRACT The food manufacturing generates a large amount of organic waste. A flavor industry, for example, can generate annually 104 and 92 tonnes of mate and guarana residues, respectively. An alternative to the reuse of this lignocellulosic material would be to use them in the production of biocomposites with fungal mycelium acting as a binder of the substrate particles. Therefore, the objective of this work was to produce fungal biocomposites of Pleurotus sajor-caju using the mate and guarana residues in a ratio of (1:1) (w/w), checking the influence of the 10, 20 and 30% inoculum fraction and the drying temperature of 40°C and 60°C. For each condition tested, mycelial growth time, initial moisture content, initial drying rate, compressive strength, air moisture absorption and water uptake were evaluated. The condition determined to produce the biocomposites was 10% of inoculum and drying at 60°C, as it presented higher resistance to compression (0.094 MPa), lower absorption of water (91%), higher drying rate (27.7 g/day). The biocomposites utilise biological growth rather than expensive energy intensive manufacturing processes and require only low-cost organic waste as feedstock, can grow to fill complex geometries presented potential for packaging, as they are safe materials that have good compressive strength and low water absorption.
DOI: 10.6084/m9.figshare.14321827
title: Production and characterization of chitosan spheres/ Dysphania ambrosioides (L.) Mosyakin & Clemants

description: ABSTRACT The objective was to produce and characterize a biomaterial in the form of chitosan spheres/ Dysphania ambrosioides (L.) Mosyakin & Clemants (mastruz) in order to associate positive characteristics of both materials, chitosan with osteoinductive potential and the bone regeneration ability of mastruz, producing a biomaterial to use as bone former and regenarator. Plant specimens were collected, identified botanically and crude alcohol extract (CAE) were obtained. For the production of the chitosan and chitosan spheres with CAE, the Ionotrope Gellification technique was used. The spheres were divided into three groups: one example group of pure chitosan; a second example group with low CAE concentration and a third example group with a higher CAE concentration; and them characterized by Optical Microscopy (OM), Scanning Electron Microscopy (SEM) and swelling degree (SD). OM showed on the external and internal surfaces, spheres with defined limits and with color changed as the percentage of CAE was increased, becoming darker. The SEM showed, in spheres with higher CAE concentration, in comparison with the ones with low CAE concentration: A decrease in size, increase in the quantity and intercommunication of the pores, and the alteration of the geometric shape of both the spheres and their pores. In the analysis of the swelling degree, there were no significant differences between the groups. It is possible to produce chitosan spheres / Dysphania ambrosioides (L.) Mosyakin & Clemants (mastruz) which in the group with the highest percentage of CAE the samples were darker and with higher amounts and intercommunication pores and that although there was swelling, no significant difference was observed between the groups.
DOI: 10.6084/m9.figshare.14321832
title: Elaboration of high temperature sintered hydroxyapatite for odontological applications

description: ABSTRACT Stoichiometric hydroxyapatite is a bioreabsorbable material and has been used for bone repair and shot blasting of titanium implants. However, the stoichiometric hydroxyapatite is not stable above 1130 oC to 1200 oC, limiting the heat treatment performed on the biomaterial to increase the mechanical strength of the granules obtained from the synthesis process at room temperature. Therefore, the aim of this work was the elaboration of calcium phosphate with Ca/P molar ratio of 1.7. With this Ca/P molar ratio, the formation of stable hydroxyapatite is possible up to approximately 1360 oC, according to the CaO-P2O5 equilibrium diagram. Calcium phosphate was prepared by the wet method of synthesis using calcium carbonate and phosphoric acid as raw materials. The material obtained from the synthesis consists of agglomerated particles with a size between 20 nm and 70 nm, while the size of the agglomerates varied from a few microns to approximately 200 µm. The results of the thermal analysis and X-ray diffraction showed that the hydroxyapatite is stable between 750 oC and 1350 oC. The heat treatment performed at 1300 oC confirmed that there is no transformation of hydroxyapatite into tricalcium phosphate above 1130 oC to 1200 oC as it happens for stoichiometric hydroxyapatite. In the heat treatment carried out at 1300 oC for 1 hour, hydroxyapatite was obtained with 67 % of porosity whereas in the treatment of 4 hours at the same temperature the porosity was 17 %. Hydroxyapatite with high porosity has applications in bone repair whereas the more compact hydroxyapatite can be used in the blasting of titanium implants. These applications are discussed in the work.