Iranian Journal of Polymer Science and Technology
Year:2002 | Volume:14 | Issue:6 (ISSUE NO. 56)|Papers Count:6

A major problem faced by the plastics industry is that of waste disposal. Recycling of used material appears to offer a solution, which is satisfactory in terms of preventing environmental pollution. Recently, increasing interest has been focused on the recycling of plastic wastes, especially PET scraps.PET is already being recycled and a number of uses have been found for it. The aim is to process and modify a mixture of virgin grade and recycled plastic with and without modifier (functionalized PP) by different extrusion methods, characterizing the properties of the modified PET and looking at different possible applications.The first stage consists of the following steps such as: collection, grinding, washing and drying the PET bottles. The second stage consists of optimization of the processing conditions, processing a mixture of virgin and recycled PET with and without the compatibilizer.The third stage consists of different methods in using to characterize the process products.The results showed that the molecular weight decreased as the blend ratio of recycling (R-PET) was increased, which is due to thermal exposure as well as shear degradation of R-PET. Thermal cycles of processing of R-PET and its blending specimens with V-PET show the importance of thermal treatment of the PET in improving it mechanical strength and increased crystallinity. By addition of functionalized pp such as PP-g-MA to the blends of 25% R-PETN/PET, the properties of the products are Improved. Crystallinity decreases while its viscosity-average molecular weight increases.

DRISPAC Polymers are one of the most effective groups of additives which are being used to depreclate the water loss dulling muds.In this work performance of the mud-free-polymer is verified at various concentrations. Furthermore, the effect of polymer DRISP AC on water loss behavior at a water-based mud (Bentonite) is investigated at various concentrations.The results show that the polymer may be considered as an effective additive, and its effect on modification of the mud behavior may be more considerable with respect to the Bentonite. In addition, at high concentration the effect of the polymer is reduced.

Sheet molding compounds as molding materials constitute a composite of a thermosetting resin and mineral fillers. These molding materials are referred as bulk or sheet molding compounds. During molding process, the objects are further treated for finishing and while still warm, they are provided with a decorative layer of powder coating materials. PMC is sprayed on the hot surface of the mold by means of an electrostatic powder coating process before the SMC or BMC is loaded. Mold temperature varies between 120°C and 170 °C, depending on the PMC grade selected. As soon as the PMC touches the surface of the mold it melts and polymerizes. After about 10 min, this layer has sufficient mechanical strength to absorb the shear forces created when SMC or BMC is being molded.

Modification of diene elastomers has obtained great popularity in rubber technology. Double bonds in a diene elastomer are suitable places for oxidative, ozone and thermal degradation reactions. Therefore, any modification on double bonds can improve elastomer resistance against these degradative conditions. In this research, a heterogeneous carbon supported palladium catalyst was used for preparing hydrogenated nitrile rubber (HNBR) and the effect of reaction parameters on hydrogenation level was investigated. FTIR and HNMR spectroscopy methods were used for determining the saturation level of the elastomer. With constant catalyst and rubber concentration, the hydrogenation level increases as pressure and time of reaction increase.

A constrained rheological model for miscible polymer blends is developed using the generic formulation. Conformation tensor with constant value is the constrain, which is introduced in general formulation using a modified mobility tensor and an energy function expressed in terms of the conformation tensor.The prediction of this family of volume preserving models is illustrated for a Hookean enerhy function and several expressions of the modified mobility tensor. Model predictions are illustrated for material functions in transient (start-up and relaxation) and steady shear flows.The sensitivity of the model for the properties functions of the blends (maximum 9 parameters for two- component miscible polymer blends) show that in steady and transient shear flows, it is possible to cover a wide range of rheological behaviors generally observed for miscible polymer blends.