Iranian Journal of Polymer Science and Technology
Year:2006 | Volume:19 | Issue:2 (ISSUE NO. 82)|Papers Count:8

In this study, the mechanical and morphological behavior of a three-component PP/PU/EVA blend is investigated. Previous studies showed that PP/PU blend is immiscible and only in the range of 70-80% of polyurethane, dispersion of PP phase in PU phase is appreciable. To increase the miscibility of the blend, ethylene-vinyl acetate was added. The Taguchi experimental design method was used to optimize the mechanical properties. Morphological studies of fracture surface by SEM and tensile test results showed that PP/PU/EVA blend with weight ratio of 20/80/5 is the optimum one.

Nowadays hot alkali treatment of cotton/polyester blend fabrics is used to impart a silk like soft handle to polyester and mercerization of the cotton. In this work, alkali treatment of 65/35 polyester/cotton fabric was performed in the same conditions as mercerization of 100% cotton fabrics, using a solution of sodium hydroxide as alkali. The effects of time, temperature and concentration of alkali solution on the rate of dye and moisture absorption of fabric were investigated. The results showed that alkali treatments of the fabric, increased dye absorption of disperse and reactive dye on polyester and cotton respectively, but it was not very effective on wetting properties of the fabric and did not observe a remarkable increasing on moisture absorption of the samples.

Due to development of spray method in painting booth in different industries, the volume of waste water including suspended paints is very high in industrial waste water. The application of coagulant-floccultor compounds is one of the efficient method for separation of paint and water recovery. In this research, at first, a novel formulation of coagulant- flocculator compound as powder material, including coagulant and flocculator agents, pH adjuster and coagulant aid, has been introduced. Then, the effects of different ingredients on coagulant-flocculator composition efficiency for separation of suspended solids (especially paint) from waste water containing paints have been investigated. Thus, a sample of waste water which contains alkyd paint (automotive paint) with concentration of 5g/L has been prepared and treated with this coagulant-flocculator compound. Therefore, the effects of polyaluminium chloride augmentation with reduction of potassium hydroxide, augmentation of sodium aluminates with reduction of poyaluminium chloride and use of the excess amount of polyacrylamide as coagulant component have been studied. The results show that augmentation of polyaluminium chloride and reductions of potassium hydroxide simultaneously, decrease the coagulant-flocculator compound efficiency for separation of solid content. The reduction of aluminium chloride and augmentation of sodium aluminates enhances the treatment efficiency. Also, by using an excess amount of polyacrylamide more than 0.1 g there is a decrease in solid recovery by coagulant-flocculator composition.

Electrospinning is a straightforward method that relies on electrostatic forces to produce nanofibers from polymer solutions or melts. In this research, in keeping the fibers diameters constant, it was tried to find parameters that increase the mass production rate of nanofibers without any change in fibers diameters. In order to investigate the productivity, Taylor's equation for prediction of critical voltage in electro spinning, was considered. In this study, a solution of 15 wt% concentration of PAN/DMF was used to electrospin the nanofibers. By increasing voltage from 10 kV to 20 kV, the productivity of electrospun nanofibers was increased up to 600% and the average fibers diameters decreased gradually from 380 nm to 315 nm. But by increasing voltage, a broader distribution of the diameters was obtained. Keeping the syringe needle length constant at 2.5 cm, by decreasing the diameter of syringe needle from 0.9 mm to 0.5 mm, the critical voltage was decreased from 7.9 kV to 6.3 kV and the productivity of electrospun nanofibers was increased up to 70%. At constant 0.7 mm diameter of syringe needle and by increasing the lengths of syringe needle from 1cm to 3.5 cm the critical voltage was decreased from 9.5 kV to 6.5 kV, and productivity of electrospun nanofibers was increased up to 42%. By varying the syringe needle diameter and its length, the average fibers diameters and the distribution of fibers diameters did not significantly change. In order to obtain some significant comparisons of our results, SPSS software was used to analyze variation with α=0.05 confidence intervals. Scanning electron microscopy (SEM) was used to measure the diameters of electrospun nanofibers.

Polypyrrole was prepared chemically using FeCl3 as an oxidant in an aqueous and non-aqueous media. The effect of various solutions such as water, acetonitrile, ethylacetate, methylacetate, methanol, ethylmethyl ketone and also the effect of different types of additives such as poly (ethylene glycol) and poly (vinyl acetate) on the films characteristics (conductivity and morphology) were studied. The results indicated that the morphology of polymer and its electrical conductivity are dependent on the type of solutions and additives. The best electrical conductivity was obtained when an aqueous solution and non-aqueous solution of ethylacetate were used.

The role of conductive polymers was studied in removing chromium from chromium plating industry waste water and the results were compared with different absorbents. The results indicated that polyaniline has the desirable effect in chromium ion removal with 59.6%, but polypyrrole has removing effect of 8.2% in similar conditions. The role of conductive polymer composite in chromium removal was studied and the results show that the percentage of chromium removal has increased in conductive polymer composite with poly (vinyl alcohol). In case of a composite of polyaniline and quartz, the chromium removal percentage from waste water decreased in comparison to polyaniline without quartz but with polypyrrole and quartz composite, the chromium removal percentage from waste water increased in comparison to polypyrrole without quartz.

Bisphenol A (4,4'-isopropylidene diphenol) BPA, a white solid, is composed of two phenyl groups attached to central carbon of propane molecule with molecular weight of 228 g/mol and melting point of 157°C, and has various interesting industrial application. In conventional methods inorganic acids such as hydrochloric acid or sulphuric acid, are used as catalyst. Today, ion exchange resins instead of acids are used as catalyst and the most important available commercial resin is divinyl benzene (DVB) based on polystyrene. In this study, BPA was synthesized using condensation reaction of acetone with phenol in the presence of modified and unmodified ion exchanged resin and the yields of the reaction were compared. This reaction is deactivated in the presence of water, so it is very important to keep its water content below 4%. To decrease resin water content and impurities, it is necessary to wash it first with water "to reach pH 4.5-5", and then with phenol till its water content reaches the desirable value. The promoter is used to increase reaction rate which is usually down with mercaptan promoter. With this procedure the purity and BPA yield are increased. The obtained BPA was characterized with IR, H NMR and DSC after purification.

The thermal, thermomechanical, rheological and morphological properties of compatibilized blends of poly (trimethylene terephthalate), PTT, and a metallocene linear low density polyethylene (m-LLDPE) at two different reverse compositions, i.e. 75/25 and 25/75 have been studied. These blends contained various levels of a glycidyl methacrylate- based terpolymer used as an interfacial modifier. Analysis of DSC results revealed that the compatibilizer has eased the crystallization process of m-LLDPE and increased its overall degree of crystallinity. On the other hand, dynamic mechanical analysis showed that glass transition temperatures of the two main components of the blends have shifted towards each other by addition of the compatibilizer. Morphological investigation revealed that addition of the compatibilizer results in decrease of size and size distribution of the minor phase for both of the blend compositions. Blends with PTT as the matrix showed the maximum reduction of size of the minor phase at 2.5 wt% compatibilizer content while the other blends with m-LLDPE as the matrix showed the maximum reduction at 5 wt% which is an indication for saturation of interface by interfacial modifier leading to a diminish in the effectiveness of the compatibilizer beyond certain level. The rheological studies also showed that up to a certain critical level of the compatibilizer, the storage and loss modulus as well as complex viscosity of the blends have increased and beyond which all these parameters have shown sharp reduction. Formation of the compatibilizer micelles above the critical micelle formation concentration, which can act as a plasticizer, is supposed to be the main reason for such changes.