1-methylimidazole (DY 070, Huntsman, Germany) was used as curing agent. Three different types of thermoplastic epoxy resins (NPES-903, Nan Ya epoxy resin, Taiwan; Epotec YD 012, Aditya Birla Chemicals Ltd, Thailand and Epiran-01, Khozestan petrochemical, Iran) were used as the capsulation agent. Epikote 828 was purchased from Momentive Co (USA), used as the host polymeric matrix. Characteristic properties of the used epoxy resins are tabulated in Table 1. Figure 1 shows the chemical structure of these epoxy resins that are diglycidyl ether of bisphenol A. In these epoxy resins the liquid epoxy has an n value 1 or blow and the solid epoxy has n value above 1. Sodium dodecyl sulfate (SDS) emulsifier and acetone solvent were purchased from Aldrich.
Microencapsulation procedure
An aqueous phase of the emulsifier was prepared containing 200 mg dissolved SDS in 200 mL distillated water. 1-methylimidazole (1-MI) and a solid epoxy resin, at three SER to 1-MI rations (30/70, 50/50 and 70/30) were dissolved in acetone (15 mL) and gently added to the continuous aqueous phase (1 wt% SDS in distilled water) under mechanical stirring (RZR 2102, Heidolph) at 500, 1000 and 1500 rpm to achieve an O/W
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For epoxy resin systems containing 20 phr microcapsules prepared at mixing speed of 500 rpm in different SER/1-MI ratios, gel times values are almost constant, and therefore the 1-MI content of these microcapsules nearly were not changed. Besides, by increasing the initial quantity of NPES-903 for preparing microcapsules at mixing speed of 1500 rpm, gel time value of epoxy resin systems containing 20 phr of these microcapsules increases (Figure 8) or the 1-MI content of these microcapsules decreases. Because of in constant microcapsule concentration, different in gel times relate to 1-MI contents (Figure 3). These confirm the TGA
The boiling point of the product was conducted with the silicone oil. Lastly, for each chemical test, three test tubes were prepared with 2-methylcyclohexanol, the product, and 1-decene in each test tube, and a drop of the reagent were added to test tubes. The percent yield was calculated to be 74.8% with 12.6g of the product obtained. This result showed that most of 2-methylcyclohexanol was successfully dehydrated and produced the product. The loss of the product could be due to the incomplete reaction or distillation and through washing and extraction of the product. The boiling point range resulted as 112oC to 118oC. This boiling point range revealed that it is acceptable because the literature boiling point range included possible products, which are 1-methylcyclohexene, 3-methylcyclohexene, and methylenecyclohexane, are 110 to 111oC, 104oC, and 102 to 103 oC. For the results of IR spectroscopy, 2-methylcyclocahnol showed peaks at 3300 cm-1 and 2930 cm-1, which indicated the presence of alcohol and alkane functional group. Then, the peak from the product showed the same peak at 2930 cm-1 but the absence of the other peak, which indicated the absence of the alcohol
Fire and thermal properties of PA 66 resin treated with poly-N- aniline- phenyl phosphamide as a flame retardant
Trimyristin was then processed to produce glycerol and sodium myristate using sodium hydroxide, ethanol, and water as reagents. After, hydrogen chloride and water were applied to convert sodium myristate to myristic acid via hydrolysis. In terms of reagents and product’s character, sodium myristate has the yellowish look in polar solutions like water because it is lipids that congregate into small droplet called a micelle. Thus, the nonpolar sides congregate on the inside of the micelle and polar ionic ends at the outside surface of the globule. The nonpolar inside dissolves the grease molecules and the ionic outside is washed away.
Fig. 2(A) shows the phase diagrams of IPM, water, and surfactant mixtures at the ratios of 60:40, 65:35, and 70:30 (v/v), respectively. Fig. 2(B) shows the phase diagrams of ethyl oleate, water, and surfactant mixtures at ratios of 90:10, 95:5 and 100:0, respectively. Filled circles mean self-emulsifying points, and black areas represent the self-emulsifying regions. In other area, the compositions showed inverted emulsion, gel-like form, or phase-separation. In general, when the oil content in the oil and surfactant mixtures is ≤30%, the condition of the mixtures changed from water-in-oil emulsion to a clear gel-like form and then to microemulsion. Otherwise, the dispersions showed phase separation, this result was similar to the results previously studied by Guo et al. [16]. Our finding showed that IPM + surfactant mixture (65:35, v/v) and ethyl oleate + surfactant mixture (90:10, v/v) showed the most self-emulsifying regions (Fig. 2). Overall, in contrast to IPM + surfactant mixture (65:35, v/v), ethyl oleate + surfactant mixture (90:10, v/v) showed finer emulsion in larger self-emulsifying range. These results indicate that ethyl oleate and Tween 80:Carbitol (90:10, v/v) were identified as the optimal oil
Bisphenol A (BPA) is a synthetic compound used worldwide in the manufacturing of plastics and epoxy resins. Derivatives of BPA are present in resin-based sealants and composites used in dentistry.1 Some of these compounds include bis-DMA (BPA dimethacrylate), bis-GMA (BPA glycidyl methacrylate) and BADGE (BPA diglycidylether).1
Z Qin et al modified ammonium polyphosphate (APP) and compared the effect of modification on flame retardant properties of polypropylene along with dipentaerythritol (DPER). The incorporation of modified ammonium polyphosphate (IMAPP) with dipentaerythritol (DPER) at 25 % loading produced LOI 32% with V-0 rating while unmodified APP had LOI 26% and V-1 rating. IMAPP also significantly decreased the PHRR and THR and contributed to the formation of compact intumescent
Methyl benzoate (0.20 ml), Sulfuric acid (0.45 mL of 18 M), and a spin vane was added to a 5 mL conical vial. An air condenser is attached and clamped to allow proper stirring. A second ice bath was made to hold a 3-ml conical vial of Sulfuric acid (0.15 ml of 18M), and Nitric acid (0.15 ml of 16M). This was added dropwise at two and half minutes per drop to the 5 mL conical vial. This was done slowly so as not to produce TNT. Once completed, the 5 mL vial containing the solution was allowed to warm up to room temperature and sat for 15 minutes undisturbed. Two grams of ice was placed in a 30 mL beaker in which the solution was poured over it. The solution was rinsed with cold water and suction filtered when the ice was melted. The crystals were washed with cold water (2 - 1.0 mL), and methanol (0.3 mL). The product was recrystallized using methanol and allowed to dry. The final beige crystals were weighed, and tested for quality.
So what exactly is Bisphenol-A? BPA is a chemical compound used to make plastic and epoxy resins and is found not just all over the world but all over your household. BPA is used to produce many of the items that we find ourselves using on a day-to-day basis: from computers to sports equipment, eyeglass lenses and compact discs to the epoxy resin function which is found in adhesives, paints, dental sealants and on the inside of canned foods.
Gelatin cryogel sheets (5%) were synthesized using glutaraldehyde as the cross-linker. The aldehyde groups of glutaraldehyde form covalent imine bonds with amino groups of gelatin. Initially different concentrations of gelatin were used (4%, 5%, 6% and 8% respectively). On physical examination of the cryogels produced with these concentrations, it was observed that at higher concentration of gelatin polymer (8%) the rate of polymerization was very fast and hence cryogel sheets formed were not proper. As the percentage of gelatin was increased the amount of cross-linker required was low i.e., the amount of cross-linker required decreases with increase in monomer concentration. Increase in polymer concentration also leads to less elasticity in the cryogel. Standardizations done for the synthesis of optimum concentrations of Gelatin and glutaraldehyde required is given in Table 1.1.
The contraction moulding method can be used to process an acrylic denture base. In this method, bite blocks are fabricated in the lab and sent to the clinic for patient trial. These are then received from the clinic and teeth are mounted onto the bite blocks. The wax is eliminated and teeth are pressurized and attached onto a gypsum mould. (McCabe and Walls. 2008.) Sodium alginate is applied onto the mould to act as a separator to prevent any monomer from the acrylic base seeping into the base and the mould. Acrylic PMMA is applied onto the mould and either heat-cured or auto-polymerized. Both of these curing methods form the...
Step 6: The ethyl ester on (20) is hydrolysed using concentrated sulphuric acid in a refluxing 1:1 acetic acid/water mixture.
The solvent should be easily removed from the purified product, not react with the target substances, and should only dissolve the target substance near it’s boiling point, but none at freezing. A successful recrystallization uses minimum amount of solvent, and cools the solution slowly, if done to fast, many impurities will be left in the crystals. Using the correct solvent, in this case ice water and ethyl acetate, the impurities in the compound can be dissolved to obtain just the pure compound. A mixed solvent was used to control the solubility of the product. The product is soluble in ethanol an insoluble in water. Adding water reduced solubility and saturates the solution and then the crystals
With the increased cost of manufacturing, pharmaceutical companies have been divesting in their smaller or less profit making operations and focus on large segments. Many Pharmaceutical companies sold their manufacturing sites to contract manufacturing organizations. The dynamics of interfacing with contract manufacturing organization added intricacy in pharmaceutical supply chain network of pharmaceutical companies.
The performance curves based on the ethylene glycol solution will be compared to those developed using water as the base to examine the effect, if any, the viscosity and density of the liquid has on the pump.
These materials covered the area of 1970s to 2000. As long as they posses the biocompatibility and biofunctionality some new and important characters were also introduced as wel...