Structure Of Resin Research Articles

Development and Characterization of an Environmentally Friendly Soy Protein-Modified Phenol–Formaldehyde Resin for Plywood Manufacturing

Most wood-based panels were currently prepared using aldehyde-based adhesives, making the development of natural, renewable, and eco-friendly biomass-based adhesives a prominent area of research. Herein, the phenolic resin was modified using a soybean protein isolate (SPI) treated with a NaOH/urea solution through a copolymerization method. The physicochemical properties, chemical structure, bonding properties, and thermal properties of the soybean protein-modified phenolic resin (SPF-U) were analyzed using Fourier transform infrared spectroscopy, thermogravimetric analysis, and formaldehyde emission tests. The results indicated that the molecular structure of the soy protein isolate degraded after NaOH/urea solution treatment, while the gel time was gradually shortened with increasing NaOH/urea solution-treated soy protein isolate (SPI-U) dosages. Although the thermal stability of the soy protein isolate was lower than that of the phenolic resin, the 20% SPF-U resin demonstrated better thermal stability than other modified resins. The PF modified with 30% SPI-U (SPF-U-3) exhibited the lowest curing peak temperature of 139.69 °C than that of the control PF resin. In addition, all modified PF resins exhibited formaldehyde emissions ranging from 0.18 to 0.38 mg/L when the SPI-U dosage varied between 20% and 50%, thereby meeting the E0 plywood grade standard (≤0.5 mg/L).

Structure, properties and reaction mechanism of formaldehyde-free melamine-urea-glyoxal co-polycondensation resin

To reduce the harmful effects of free formaldehyde released from wood-based panel on human health and the environment, in this study, melamine-urea-glyoxal (MUG) resin was synthesized by using low-toxicity and biodegradable glyoxal instead of formaldehyde. It provides a comprehensive discussion on the structures, reaction mechanisms and properties of MUG resins with different molar ratios were compared and analyzed. FT-IR, 13C NMR, and XPS confirmed the co-polycondensation reaction between M, U, and G. However, with the change of raw material ratios, the structures of the MUG resins were less affected, the properties of the MUG resins were obviously different. When the molar ratio is R = n(M): n(U): n(G) = 0.16:0.30:1.0, thermal analysis showed that MUG plywood had better thermal stability. Evaluation of the gluing properties revealed that the dry and wet strengths of MUG adhesive bonded plywood reached 1.21 MPa and 0.91 MPa, respectively. In contrast to reported glyoxal-related wood adhesives, the MUG adhesive displayed much higher bonding strength, vastly superior water resistance. This study provides a new green pathway for the development of new urea formaldehyde adhesives, which helps to enhance their potential application value in the wood industry.

Analysis on Degradation Mechanism and Product Recycle of Ex-service Wind Turbine Blades by Hydrothermal Liquefaction.

The recycling of ex-service wind turbine blades (EWTBs) presents a significant challenge for the future. Hydrothermal liquefaction (HTL) has emerged as a promising approach for the recovery of resins and glass fibers (GFs) from EWTBs. This study offers a comprehensive analysis of the separation mechanisms and product characteristics under the catalytic effect of an acidic medium during the HTL tests. The primary factors were identified as hydrothermal temperature and H2SO4 concentration. The acidic medium facilitated disruption of the resin's structure by supplying hydronium ions, while temperature played a crucial role in determining the yield of oil-phase products. Operating conditions of 280 °C and 0.6 mol/L H2SO4 resulted in an oil-phase yield of 98.2%. The cleavage of cross-linked C-N and C-O-C bonds reacted with hydrogen ions to produce stable compounds, primarily phenol and p-cumyl alcohol. Based on these findings, two distinct mechanisms of resin depolymerization were proposed, depending on the sequential cleavage of C-O-C and C(benzene ring)-C(isopropyl) bonds. Intermediates, including bisphenol A and 2-propanol,1,3-diphenoxy-, were generated. They further decomposed into smaller units, eventually forming phenol. Moreover, temperature was found to be a critical factor in determining the strength of recycled glass fibers (RGFs). The optimal conditions of 260 °C and 0.6 mol/L H2SO4 concentration were identified as being capable of achieving complete resin depolymerization while preserving high-strength RGFs. These innovative findings provide valuable insights into the development of low-temperature, high-efficiency methods for the full-component recovery of EWTBs, offering significant guidance for future recycling efforts.

Comparative Analysis of the Compositions of the "Kerkuri" Resins with Different Ratios of the M And Q Units

The compositions and structures of methyl MQ resins with different M/Q ratios were studied using NMR and IR spectroscopy, as well as gel permeation chromatography (GPC). It was found that the M/Q ratio affects the molecular weight of the siloxanes under consideration and the activity of hetero- and homopolycondensation. Depending on the M/Q ratio, MQ resins can act as plasticizers or reagents.

Synergy between biphenyl mesomorphic structure and organic crystal phenazine for improving the intrinsic thermal conductivity of epoxy

The inherent low intrinsic thermal conductivity of epoxy resin severely restricts its potential application, making it difficult to meet the growing demand of energy, electrical and electronic technologies. The liquid crystal epoxy resin, which is wildly employed to improve the intrinsic thermal conductivity of epoxy resin, is constrained by its complex molecular structure design and synthesis procedures. In this work, the rigid group of 4,4′-dihydroxybiphenyl was introduced into the main chain of epoxy resin by ring-opening polymerization (ROP) to change the molecular structure of epoxy resin. The introduction of biphenyl groups enhances the orderliness of molecular structure and forms hydrogen bonds between molecules, which further enhances the transport of intramolecular phonons. The thermal conductivity of the graft modified epoxy resin (GMR) after DDM curing is 0.30 W m−1 K−1. After adding of organic crystal phenazine (PNE) to the GMR matrix, the inherent strong crystallization behaviors of PNE can accelerate the regularity arrangement of rigid groups in GMR, and promote the nucleation and crystallization process of GMR/PNE. The thermal conductivity of GMR/PNE after DDM curing can reach 0.33 W m−1 K−1. It is 165 % of the thermal conductivity of traditional epoxy resin, which is 0.2 W m−1 K−1. This study will provide a new method to improve the intrinsic thermal conductivity of polymer materials.

A novel simulation of space charge decay dynamics after removing the voltage in epoxy resin composites

Abstract Epoxy resin serves as a critical insulating component in ultra-high voltage dry direct current bushings. However, the accumulation of space charges within the epoxy resin, a byproduct of charge mobility, poses a significant risk to the reliability and operational safety of bushings. Conventional space charge attenuation models, especially after voltage removal, have limited use in simulations aimed at understanding this phenomenon. This study introduces an improved model integrating the bipolar charge transport mechanism with space charge decay based on the hopping conduction mechanism and Schottky’s theorem, establishes a theoretical framework for predicting the space charge behavior following voltage removal, and conducts a simulation to investigate the decay process within the internal structure of epoxy resin and measure the residual charges after voltage removal using the pulsed electro-acoustic method. The experimental data validate the accuracy of the proposed model and theoretical assumptions. The findings show that the remaining negative charges after voltage removal are not enhanced by the field enhancement; the anodic positive and cathodic positive charges are distributed in two-segment discontinuous traps, whereas the negative charges are distributed in one-segment traps. The model identifies two distinct trapping sites for anodic and cathodic positive charges, and one trapping site for negative charges. After voltage removal, when the field strength exceeded 40 kV mm−1, positive charges exist near the upper and lower electrodes, and negative charges exist near the center of the specimen. The consistency between the simulated predictions and experimental data proves the effectiveness of the proposed model in accurately simulating the space charge decay in epoxy materials after voltage removal.

Bio-Based Epoxy-Phthalonitrile Resin: Preparation, Characterization, and Properties.

Preparation of high-performance thermosetting resins via bio-based resources is important for the development of a sustainable world. In this work, we proposed the introduction of cyanide structure groups into the molecular structure of epoxy resins to give them excellent heat resistance. A eugenol-based epoxy-phthalonitrile (EEPN) resin was synthesized by a two-step process using the bio-based renewable resource of eugenol, and a series of EEPN/Epoxide resin (E51) blend resins with different EEPN contents were prepared. The structure of the EEPN monomer was characterized and confirmed by Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and elemental analysis. The thermal stability and dynamic mechanical properties of the cured resins were investigated by thermogravimetric analysis and dynamic mechanical thermal analysis. The experimental results showed that EEPN had excellent heat resistance; the char yield at 800 °C was 67.9 wt%, which was much higher than that of E51 at 26.3 wt%; and the heat resistance of the blended resins was significantly improved with the increase in the EEPN content.

Stable Radicals in Dihydrophenazine Derivatives-Doped Epoxy Resin for High Photothermal Conversion.

Organic radicals exhibit great potential in photothermal applications, however, their innate high reactivity with oxygen renders the preparation of stable organic radicals highly challenging. In this work, a series of co-doped radical polymers ares prepared by doping dihydrophenazine derivatives (DPPs) into the epoxy resin matrix. DPPs can form radical species through the electron transfer process, which are further stabilized by the complex 3D network structure of epoxy resin. Experimental results show that the photothermal conversion efficiency is as high as 79.9%, and the temperature can quickly rise to ≈130°C within 60 s. Due to the excellent visible light transmittance and mechanical properties of co-doped systems, this study further demonstrates their practical applications in energy-saving solar windows and thermoelectric power generation.

Preparation and performance characterization of waterborne epoxy resin modified asphalt emulsion for tack coat

In order to eliminate the possible drawbacks of waterborne epoxy resin (WER) generated by the phase inversion method and the chemical modification method, this study prepared WER using a novel method, i.e., epoxy resin was introduced into the molecular structure of aqueous acrylic resin; after the combination of epoxy resin and the aqueous dispersion process, the aqueous epoxy acrylic resin can be prepared. Waterborne epoxy resin modified emulsified asphalt (WEREA) was then prepared for the application of a tack coat material. Fourier Transform Infrared Spectroscopy (FTIR) test was conducted to explore the possible reactions between the compositions. A rheology test, direct tension test, pull-off bonding test, and oblique shear test were also conducted. Results indicated that in the FTIR test, a new peak around 1732 cm−1 was formed due to the reaction between the carboxyl functional group in WER and the amino group in curing agent to form an ester bond. The incorporation of WER led to an elevation in the complex modulus and a simultaneous reduction in the phase angle of WEREA. When the temperature was larger than 60 °C, the phase angle showed a decreased trend, indicating the material became less viscous due to the increased temperature, illustrating thermosetting characteristics of epoxy resin. As the content of waterborne epoxy resin (WER) increased, there was an observed decrease in the direct tensile rate, coupled with a concurrent increase in direct tensile strength. When the ratio of emulsified asphalt and WER was 1:0.6, the tensile strength of WEREA increased by 811% in contrast to the specimen without the inclusion of WER. There existed different optimal WER contents for the pull-off strength tests conducted on different substrates. For asphalt concrete substrate and steel slab substrate, the optimum ratio of emulsified asphalt to WER + curing agent was 1:0.4, and 1:0.8 was the optimum ratio for the cement concrete substrate. When the ratio between emulsified asphalt and the combination of WER along with the curing agent was 1:0.4 (WEREA-4), the oblique shear strength obtained the maximum value, which was increased by 18.7% in contrast to WEREA-0.

Rational design of a room‐temperature curing method, based on the epoxy–thiol click reaction, for UV‐curable hard coatings with ultrahigh strength and adhesion

AbstractIn recent years, there has been a growing demand for UV‐curable hard coatings because they offer several advantages, for example, lower energy consumption and the absence of volatile organic compound emissions. Anionic UV curing with photobase generators (PBGs), such as epoxy–thiol cross‐linking, enables curing under ambient conditions. However, designing a room‐temperature photoanionic curing system for epoxy–thiols remains challenging due to the complex effects of resin combinations on the cured products, thus making it difficult to prepare films with high hardness. Herein, we present a controlled reaction design for an anionic UV‐curing system by combining the chemical structures of epoxy resins and multifunctional thiols. The anionic UV‐curing system using PBGs that generate organic superbases demonstrated UV‐delayed curability, as evidenced by FT‐IR and photorheological analyses. To achieve high hardness, it was necessary to create the thiols with ultrarigid structures; epoxy resins with a bisphenol F structure were optimal for reacting with thiols for ultrarigid structures. This combination afforded an indentation hardness of 262 MPa with an epoxy conversion rate of 77% even at room temperature.

Why should a bioengineering lab have engineers and health professionals?

Through the description of the methodology of the development of a bite force measurement device it will be shown how interdisciplinary work of Engineers and Health Professionals bring enhance of life quality to general population. Bite force measurement is a reliable exam to check stomatognathic system (SS) conditions. In order to provide a reliable, low cost and do-it-yourself gnathodynamometer a Dentist joined Bioengineering Laboratory (LabBio) at UFMG. The development of a 3D printed resin structure was made using CAD/CAM and tested by means of FEM. A Carbon Nano Tube (CNT) extensometer developed at CTNANO at UFMG to capture the structure deformation were fixed in two geometries that showed good results in FEM simulation and will be tested in an EMIC universal mechanical testing machine (DL1000) equipped with a 1 kN load cell. The electrical response of the extensometers was monitored using a Keithley 2000 digital multimeter (Tektronix), connected to a computer and remotely controlled by a LabView application (View Point Systems), a data storage protocol in a SD card and in the clouds using IoT and an data acquisition system will be tested. In bench tests both geometries showed good results with deformation capturable from 40 N. Data was codified using an Arduino Nano and a program was developed for data acquisition and storage. The interdisciplinary work generates prototypes with promising results in bench tests. The fruit of the team work may generate a toll that improves life quality of population by allowing more people to be tested and lowering health costs.

Preparation of dodecahydrate disodium hydrogen phosphate shape-stabilized composite phase change materials and their experimental investigation in solar thermal storage and exothermic systems

To alleviate the mismatch between energy supply and demand caused by the spatial and temporal distribution mismatch and weather uncertainty during solar energy utilization, solar energy is combined with phase change thermal storage technology to improve the performance of solar thermal storage systems. In this study, a shape-stabilized composite phase change material with a highly absorbent resin structure is proposed as thermal storage material. This material exhibits a latent heat of phase change of 246.5 J/g, a thermal conductivity of 1.968 W/(m·K), and maintains good stability after 200 thermal cycles. Subsequently, a detachable experimental setup integrating solar energy with a phase change thermal storage tank was designed and constructed. The effects of inlet and outlet hot water flow rates and heat source temperature on heat storage time and the amount of stored water were investigated separately. The experiments show that increasing the heat source temperature during storage effectively shortens the storage time, and that the largest effective amount of hot water is obtained when the exothermic flow rate is 300 L/h. The study's results are significant for broadening solar energy utilization, alleviating the mismatch between solar energy supply and demand, and evaluating the thermal performance of latent heat storage systems.

Research of influence of diluent on the mechanical behavior of triaxial warp-knitted composites

The composites are prepared by different processes of reinforcement and matrix, which are affected by the properties of reinforcement and matrix. In this study, composite specimens were fabricated using vacuum-assisted resin infusion (VARI) with varying mass fractions (0%, 5%, 10%, and 15%) of a diluent mixed with the resin and curing agent, serving as the matrix. Triaxial warp-knitted glass fabric was employed as the reinforcement material. The impact of the diluent mass fraction on the bending, impact, and creep properties of the composites was investigated. The least squares fitting method was applied to analyze the experimental data, leading to the establishment of a mathematical model correlating the diluent mass fraction with the bending strength. The optimal diluent mass fraction for achieving the best bending properties was determined. Furthermore, the failure mechanisms of the composites were examined through an analysis of their thermodynamic properties, reaction principles, and fracture morphologies. The results show that the epoxy group in the diluent will be connected to the cross-linking network structure of epoxy resin by ring-opening reaction, and excessive addition will lead to the increase of flexible chain segments, which makes the mechanical properties of the specimens increase first and then decrease. The mathematical model was verified by experiments, and the mass fraction of diluent was 9.65% when the bending property was optimal.

Siloxane-containing epoxy resins derived from magnolol with low dielectric properties, excellent toughness, and flame retardancy

The entanglement disorder, highly polar groups and carbon-rich structure of conventional epoxy resins result in high dielectric constants and flammability, posing challenges to the development of high-frequency communications. Therefore, a silicone-containing active ester curing agent (FMAE) derived from magnolol was synthesized via a straightforward two-step process. And a thermosetting resin (FMAE/TGDDM) was then obtained by moisture self-cross-linking as well as curing epoxy N, N, N, N-tetraethoxypropyl-4, 4-diaminodiphenylmethane (TGDDM). The epoxy resin (MAE/TGDDM) cured by MAE that was not undergoing click chemistry was used for comparison. The results showed that the large volume of curing agents (31.86 Å × 14.98 Å × 9.03 Å for FMAE, 16.01 Å × 11.46 Å × 8.09 Å for MAE) and the absence of –OH enabled both resins to have excellent dielectric properties, especially FMAE/TGDDM, with a Dk of 2.78 and a Df of 0.0066 at 10 MHz. Additionally, FMAE/TGDDM demonstrated favorable impact resistance (43.9 kJ/m2) and lower hygroscopicity (0.56%) than MAE/TGDDM, which due to the introduction of siloxane chain (Si% = 7.08%) and the increase of the crosslinking density (2302 mol/cm3 vs 6751 mol/cm3). Furthermore, the charring rate of FMAE/TGDDM was 39.1%, almost twice that of MAE/TGDDM, and the PHHR and THR were 201.2 W/g and 22.6 kJ/g, 103.9% and 67.7% lower than MAE/TGDDM, respectively, proving that the intrinsic flame retardancy of FMAE/TGDDM. Hence, this paper provides a strategy to synergistically address the limitations of TGDDM and conventional epoxy resins for impact resistance, dielectric properties and flame retardancy through a simple structural design.

THE EFFECT OF TREATING HEAVY OIL WITH ISOPROPYL ALCOHOL ON THE COMPOSITION AND STRUCTURE OF RESINS

The effect of heavy oil treatment with isopropyl alcohol (IPA) for 8 h at a temperature of 25-100 °C on the composition and structure of resins is investigated. The objects of investigation were heavy oil from the Zyuzeevskoye field (the Republic of Tatarstan) and resins isolated from this oil. It is established that the resin content increases by almost 3 wt% as a result of heavy oil treatment with IPA at 100 °C. It is shown than an increase in the temperature of oil - IPA (20 wt%) mixture treatment from 25 to 100 °C causes an increase in sulphur and oxygen content in resins by 0.5 and 0.8 wt%, respectively, and a decrease in the Н/С atomic ratio from 1.40 to 1.38. The aromaticity factor of resins increases by 0.17 %, while the fraction of aliphatic carbon decreases. It is concluded that oil treatment with isopropyl alcohol, aimed at a decrease in the content of resinous and asphaltenic substances, is unreasonable because it causes unfavourable formation of the additional amount of resins.

An ionic liquid in Core-shell structure: Halogen-free, metal-free bifunctional catalyst for olefin epoxidation and CO2 cycloaddition

We synthesized a core-shell resin structure with abundant architecture and excellent thermal stability through polymerization. Imidazole ionic liquid with varying carbon chain lengths was immobilized on the surface, resulting in the preparation of metal-free, halogen-free core-shell catalysts with different carbon chain lengths via HCO3- exchange. Characterization using FT-IR, XPS, and various techniques revealed the exceptional performance of our synthetic catalyst in terms of its internal structure. After extensive experimentation, we discovered that the synthesized catalyst exhibits dual functionality for epoxidation and CO2 cycloaddition reactions without requiring solvents or co-catalysts. The epoxidation system demonstrated remarkable conversion rates and selectivity while also exhibiting strong recyclability in heterogeneous reactions, according to kinetic parameters, the reaction order of styrene, TBHP and catalyst during epoxidation is approximately 1, the reference factor for this reaction was calculated to be 6.7×109 (L2·mol−2·min−1), with an activation energy of 48.9 kJ/mol obtained from analyzing reaction rates at different temperatures. In the CO2 cycloaddition reaction, our catalyst exhibited an advantage in catalyzing ring-opening reactions, achieving a conversion rate of 95 % for styrene oxide within six hours along with over 99 % selectivity towards cyclic carbonate formation. It is suggested that the epoxide reaction is carried out in steps, and it is inferred that the catalyst PS-ImC4HCO3 and TBHP are produced into peroxy intermediate active species TBA and HCO4, and the reaction between HCO4- and styrene is the determination step of the total reaction. The reaction rate constant k=0.009 of the absolute step is calculated based on the global optimization algorithm

Synthesis of novel reactive flame retardant to improve fire resistance and mechanical properties in epoxy resin

A novel reactive flame-retardant (FR), phosphorus-modified tetraethylenepentamine (TEPA-m-MVP), was prepared via aza-Michael addition process, using dimethyl vinylphosphonate (MVP). TEPA-m-MVP was successfully covalently introduced into the structure of the epoxy system, into the epoxy resin matrix synthesised from tetraethylenepentamine (TEPA) and diglycidyl ether bisphenol A (DGEBA) reaction, leading to the development of a flame-retardant epoxy resin (FR-EP). The curing behaviour, mechanical properties, thermal stability and flame-retardant behaviour of FR-EP samples were investigated and compared to the behaviour of the neat epoxy resin (EP). FR-EPs showed an increase in glass transition temperature (Tg), from 120 to 147 °C upon integrating TEPA-m-MVP into the epoxy resin structure, while the value of the E modulus remained unaffected. Furthermore, FR-EP-2%P sample with the optimal P content, approximately 2 wt%, displayed excellent flame-retardant properties. In comparison to EP, total heat release (THR) and peak heat release rate (pHRR) for FR-EP-2%P decreased from 22.6 to 15.3 kJ.g−1 and from 1557 to 572 kW.m−2, respectively. In addition, an interesting impact of the crosslinking density of FR-EP samples on the fire behaviour was observed. This work presents a new strategy for the simultaneous modification of the flame retardancy and mechanical properties of epoxy systems.

Impact of ligand structure and base bead pore size on host cell protein removal during monoclonal antibody purification using multimodal chromatography resin

Despite advancements in therapeutic monoclonal antibodies (mAbs) and cell line engineering, separating host cell proteins (HCPs) from mAbs during downstream purification remains challenging. Therefore, in this study, we developed a novel multimodal chromatography (MMC) resin to enhance HCP removal during mAb polishing processes. We evaluated the impact of both ligand structure and pore size of the MMC resin by purifying a post-protein A chromatography solution in flow-through mode. We observed that the efficiency of HCP clearance depended on the hydrophobic moiety structure of the ligand and predicted the mAb purification capability of MMC through linear salt-gradient elution experiments involving a mixture of transferrin, bovine serum albumin (BSA), and pepsin. Our findings revealed that the prototype immobilized 1,12-dodecanediamine via the formyl group exhibited the best performance attributed to its long alkyl chain. Furthermore, an investigation of effects of base bead pore size on HCP capacity using cellulose base beads of five different pore sizes showed that larger pore resin base beads had the highest HCP removal capacity. Specifically, MMC resins with a pore diameter exceeding 440 nm reduced the HCP level by three orders of magnitude under high mAb loading conditions (> 1000 mg/mL-resin). The MMC resin developed in this study, along with the insights gained into ligand structure and pore size, not only enhances mAb polishing efficiency but also contributes to improving downstream processes in mAb biopharmaceutical production.

Rapid repair and degradation: A study of high-performance recyclable vitrimer epoxy resin based on disulfide bonds

Petroleum-based epoxy resin is commonly used in electrical equipment due to its outstanding performance and affordability. However, its non-melting characteristics present challenges for recycling, leading to significant resource waste and environmental pollution. To address this issue, this study prepared and synthesized a kind of vitrimer epoxy resin polymer material based on disulfide bonds with 2,2′-Diaminodiphenyl disulphide as the curing agent. The research investigated the impact of the curing agent ratio on the resin's structure and properties. The resin was mechanically recovered through hot pressing at high temperature and pressure, and its chemical degradation and recovery were achieved via the reduction reaction of the thiol and disulfide bond. The findings revealed that a curing agent to epoxy group material ratio of 0.75 improved the resin system's electrothermal properties. The electrical insulation property retention rate after hot pressing recovery reached 95 %, with a mechanical property retention rate of 85 %. The disulfide bonds can be reoxidized and crosslinked to realize the recovery and reuse of vitrimer resin degradation solution. Vitrimer epoxy resin based on disulfide bonds is a significant way to realize the environmental protection of epoxy electrical equipment.

One-Pot Liquid-Phase Synthesis of Methyl Isobutyl Ketone Over Bifunctional Ion-Exchange Resins: Unravelling the Role of Resins Structure and Active Pd or Cu Phases on Sintering, Leaching and Catalytic Activity

One-Pot Liquid-Phase Synthesis of Methyl Isobutyl Ketone Over Bifunctional Ion-Exchange Resins: Unravelling the Role of Resins Structure and Active Pd or Cu Phases on Sintering, Leaching and Catalytic Activity