Formation and Properties of Epoxy Resins Containing PES Copolymer Modifiers

Two epoxy network-forming systems based either on a diglycidyl ether of bisphenol A (Epikote 828) or a triglycidyl p-amino phenol (MY051 0), were crosslinked using stoichiometric amounts of 4,4'-diaminodiphenyl sulfone (DDS). Both epoxy systems were modified with random copolymers, polyethersulfone-poly( ether-ethersulfone) (PES:PEES), with either amine- (NHz-) or chlorine- (CI-) end-groups, at I 0 and 20 wt %. The Epikote 828/DDS (ED) and MY051 0/DDS (MD) systems were reacted at 190 and 180 °C, respectively, and all the unmodified and modified epoxy systems were prepared without the use of solvent. Real-time analytical techniques were used to study network structure development through investigations of polymerisation kinetics using DSC and FTIR spectroscopy. and of gel times and power-law behaviour using rheometry. DSC has limitations for the measurement of chemical conversion, particularly as crosslinking reactions approached completion. As an alternative, FTIR spectroscopy in the near-infrared frequency region was refined and improved to provide more accurate conversiontime data. Overall, the reaction mechanisms were autocatalytic in nature independent of the PES:PEES concentration. Gel-point conversions, PgeJ, were determined from combined DSC and rheology data. Values of Pgei for unmodified ED and MD systems were 0.61 ± 0.01 and 0.50 ± 0.02, respectively, compared with 0.58 and 0.41, as predicted by Flory-Stockmayer statistics, for the corresponding ideal networkforming systems. The gel times, lgeJ, in the epoxy network-forn1ing systems were delayed by incorporating PES:PEES, which acts as a diluent. although gel conversions were unaffected. In addition, a posteriori characterisation of the fully-reacted network materials was carried out using TMDSC, DMA and tensile tests, SAXS. SEM and TEM to evaluate the thermal and mechanical properties in relation to morphological structures. The modified ED systems were miscible at the molecular level as shown by SAXS analysis. In contrast the modified MD systems were phase-separated. Co-continuous and phase-inverted morphologies were generated in MD systems containing. respectively, 20 wt % of amine-and chlorine-terminated PES:PEES. Differences in the morphologies between modified ED and MD systems were related to differences in crosslink densities of the epoxy networks. In the phase-separated systems, the Tg of PES:PEES-rich phases shifted to higher temperatures, and the Tg of the epoxy-rich phases shifted to lower temperatures, as shown by TMDSC and DMA. In the rubbery state, the presence of PES:PEES in the epoxy systems was shown to increase the molecular weight between crosslinks, Me. so decreasing the crosslink density. The increase in Me with increasing modifier content was attributed to a swelling effect in the epoxy network by molten PES:PEES. Incorporating PES:PEES in the epoxy network systems increased the ductility of the unmodified epoxy systems. This was shown by SEM on epoxy fracture surfaces carried out after tensile testing. Modified epoxy systems increased tensile properties such as strain at break, strength and toughness with only slight reductions in the Young's modulus. The tensile toughness of the modified ED and MD systems containing 20 wt% NH2-PES:PEES were increased by 130 and 300 %, respectively

Production Of Activated Carbon From Sawdust Using Fluidized Bed Reactor.

Activated carbon was produced from sawdust by using steam activation in a high temperature muffle furnace. Fast pyrolysis process was carried out prior in fluidized a bed furnace to produce char before activation process

Effect of Water and [Emim][OAc] as Plasticizer on Gelatinization of Starch

AbstractAs the depletion of petroleum source and environmental concerns been arises, a new polymer defined as biodegradable material had been extensively study in order to replace the synthetic one. Starch is one of natural materials that been used for producing biodegradable materials. Through gelatinization process, native starches were changed into thermoplastic starch (TPS) in the presence of water and [Emim][OAc] as plasticizers at high temperature (90˚C). The structure and interaction of starch/water/[Emim][OAc] have been study using differential scanning calorimetry (DSC). DSC analysis is used to analyse the onset temperature (To), the peak temperature (Tp), the melting temperature (Tm) and melting enthalpy (ΔH) of samples over a wide range of starch/water/[Emim][OAc] contents. Gelatinization peak shift to higher temperature as the value of [Emim][OAc] is increasing. The values of To, Tp and ΔH are influenced by the hydrogen bonding capacity of plasticizers. Thus, showed that composition of water/[Emim][OAc] is effectively influence the gelatinization process

Ionic Liquids for Desulphurization: A Review

The literature survey has shown that not much work has been reported on the interaction mechanism of ionic liquids (ILs) with sulfur in model oil system. In recently published work, the interaction was predicted using COSMO-RS where the strength of hydrogen bond of anion should be reduced in order to increase thiophene extraction capacity. On the other hand, the same researchers also found that the smaller sized cations would lead to higher selectivity, which could lower the capacity and vice versa. While others have reported that the absorption capacity of sulfur compounds in ILs are strongly dependent on the chemical structures, physical properties and compactness between the cation and the anion of the ILs. However, these conclusions lead to a broad selection of ILs for extractive desulphurization process

The compliance of contractor on providing the occupational safety system at the construction site. (Case Study - Government Projects) / Zakaria Yaa'cob, Mohamad Sohaimi Man and Dr. Md. Yusof Hamid

Now day we seen many accidents happen at the construction site, it seen is in control situation. The contract that stated the need of safety at construction site and it like the contractor did not take a serious action on it. All parties involved in the project must contribute their roles in resolving the problems. It must be study according to law and regulation such as Occupational Safety and Health Act 1974 and Machinery and Industry Act 1967 and providing the safety management system by contractor. There are two methodologies that has been used in this research, one is the literature review including safety management system, such as safety policies, safety plan, accident reporting system, training, monitoring and supervising and risk assessment, legislation. The second methodology is to do a case study on government projects by using interview to the target group that is contractor, members of professional, and safety officer. The analysis base on the finding of case study for every item discuss and the result of the analysis will show the compliance of contractor on providing the safety management system. As Conclusion, at the end of this research, a proposal to government agencies for an improvement of system at construction site

A KINETIC ANAYSIS OF THE DEGRADATION OF GRAFTED ANIONIC POLYACRYLAMIDE GEL UNDER NONISOTHERMAL CONDITION

Grafted anionic polyacrylamide gel has been synthesised in the laboratory following radical polymerisation process. Kinetics of thermal degradation of synthesised gel was evaluated under nonisthothermal condition by integral approximation method to determine the thermal stability of the material from thermogavometric study. The activation energy for the thermal degradation was found to be significantly high for the gel material

Psychrotolerant biosurfactant-producing bacteria for hydrocarbon degradation: a mini review

Biosurfactants are a structurally diverse group of surface-active substances synthesised by microorganisms. All biosurfactants have tremendous potential ranging from medicine to environmental applications especially in hydrocarbon remediation. Petroleum pollution is a major issue in both cold and temperate climate countries. These hydrocarbon pollutants have low solubility and high solid-water distribution ratios, thus limiting the interaction between microbial cells. Petroleum pollution is a major issue in both cold and temperate climate countries. In Antarctica, due to the recalcitrant nature of hydrocarbon components coupled with the region's extremely weather conditions, there were difficulties faced by bioremediation approaches. However, using biosurfactant in hydrocarbon bioremediation increases the bioavailability of hydrocarbon, thus expediting bioremediation. Few studies have reported on psychrotolerant bacterial species that are able to degrade hydrocarbon and produce biosurfactants. This review focuses on psychrotolerant bacteria with the potential to synthesise biosurfactants and degrade hydrocarbons

Formal Specification for Spatial Information Databases Integration Framework (SIDIF)

This paper discusses the formal validation for spatial information databases integration framework (SIDIF). A SIDIF database is a large, organized body of persistent data, usually associated with computerized software designed to update, query, and retrieve components of the data stored within the system. One of the common difficulties faced by the developer is in designing a robust database system. Even so, in order to solve this matter, developers have to focus their efforts on the formal specifications. The formal specification is supposed to reduce the overall development time. Formal specifications can be used to provide an unambiguous and precise supplement to natural language descriptions. Besides, it can be rigorously validated and verified leading to the early detection of specification errors. Consequently, to validate this problem formally, we specify the SIDIF database framework using Z language and prove by using Z/EVES theorem proven tool. By using this kind of tools, it may help to reduce time, energy and mistake compared to manual theorem proving which can be error task and tedious

Strategy on the production of bead free electrospun gelatin scaffolds

Electrospun scaffolds consist of micro-scale or nano-scale porous fibrous networks. These electrospun scaffolds had become increasingly popular in tissue engineering filed as it could provide nano-environment for cell culture and produced by using biodegrable polymer. One of the important key to provide such environment for cell culture is the porosity of the electrospun scaffolds as it is highly related with the cell-cell interaction. The porosity of the electrospun scaffolds could be affected by bead formation which is one of the common problems faced in electrospinning process. However, the formation of beads are difficult to be controlled as it depends on environmental factors such as humidity and operating temperature. Controlling these two environmental factors normally requires an expensive control system. This paper aims to solve the problem of bead formation by adjusting material concentration and process parameters without controlling the environmental factors. The parameters studied in this paper include polymer concentration, flow rate, distance between the syringe needle tip and collector and applied voltage. The microstructure of the electrospun scaffolds produced were visualised using scanning electron microscopy (SEM) and were analysed in terms of bead formation and fiber diameter. This study shows that polymer concentration is the best strategy to prevent bead formation in gelatin scaffolds while other process parameters such as applied voltage, distance between the syringe needle tip and the collector as well as flow rate can be used to control the fiber diameter. An understanding of the effects of each parameter provides a guideline to control microstructure morphology by producing bead-free electrospun gelatin scaffolds

Sifat mekanikal saduran epoksi mengandungi abu buangan industri

Organic epoxy coating was the primary focus of this study because of its thermosetting characteristics, high durability of adhesion to the substrate, stable structure, chemical resistance and economical cost. However, epoxy coating has several disadvantages in that it is easily cracked, brittle and sensitive to climate change due to its ability to easily absorb water. Humidity can weaken the structure of the coating. To resolve this issue, fly ash is added as reinforcement to the structure of the epoxy. Fly ash is a material that can improve the mechanical strength and durability of a coating. However, the optimum mass of fly ash in the epoxy should be studied carefully to produce an epoxy coating that is strong, stable and that does not easily absorb water. Therefore, this study was performed to synthesize epoxy resin with fly ash as filler, as well as to analyse the impact of fly ash on the properties of the epoxy coating through hardness strength tests. The characteristics of the epoxy resin with fly ash (MFA and OFA) and without fly ash (RE) were analysed by thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), and density and particle size analysis. Based on the FTIR analysis, fly ash does not change the structure of the functional groups in the epoxy. For the TGA analysis, the onset of degradation for MFA and OFA started to occur at 346 ± 1°C. The addition of 5% fly ash increased the hardness of the epoxy by up to 13% compared to the unmodified epoxy. Epoxy coatings can be improved in terms of their hardness and degradation time by the addition of fly ash as filler