Iranian Journal of Polymer Science and Technology
Year:2001 | Volume:13 | Issue:4 (ISSUE NO.50)|Papers Count:5

One of the manufacturing processes of composite materials is the resin transfer moulding, RTM, that has been the subject of much research in the last few years. This process is capable of producing complicated composite parts. To accomplish a successful molding in this process, it is initially necessary to design and manufacture a good mould. The most important factors in this regard are determination of injection port and vent locations as well as choosing the right material and a suitable structure for the mould. In this paper, therefore, after discussing the RTM process and its advantages, determination of injection port and vent locations for a complicated composite part have been studied experimentally and theoretically. The effect of glass fiber volume fraction, mould angle and the variation of thickness on mould filling time have been investigated. Results show that there is a good agreement between experimental results and computer simulation. The results also show the importance of injection and vent ports in producing.

In this work rheological behavior of polyethylene/polypropylene blends produced by Arak and Bandar Imam Petrochemical complexes was investigated. The viscosity of homopolymers, PE and PP, and their blends at different concentration proportions were measured. The measurements have been carried out by using a capillary rheometer. The results for the blends show that when two homopolymers with great difference in shear viscosity form a blend, the viscosity of the blends are intermediate between the viscosity of homopolymers. On the other hand, for the two homopolymers (PE and PP) with viscosities close to each other, the curve of viscous homopolymer falls down quickly below the viscosity of blends with high shear rate. It has been shown that the viscosity of the blends versus PE content has negative deviation from logarithmic addition rule. The modeling of viscosity of blends in respect to concentration of homopolymers has been produced and it is shown that the modified Kulezner model can predict the viscosity of the blends in terms of viscosities of original resins with very good precision.

In tyre retreading the adhesion of cushion gum layer to tyre carcass surface is an important factor which influences retreaded tyre quality. In order to study the best condition of adhesion of cushion gum to carcass, after preparing the compounds for the gum at the same condition, this compound has been cured on the surface of a reference elastomeric sheet, a system similar to tread and the carcass compound. After preparing the test sample they have been tested by T-Peel test method (ASTM1876-93). Through these tests results, the effect of several surface treatment methods before curing, type of accelerator used in curing system and also the effect of blending of natural rubber (NR) with a synthetic rubber (SBR, BR) on bond strength were evaluated.Initial compounds Were mixed by a Farrel banbury with maximum capacity of 1.5 L and then masticated by a shoubenthan polymix 200L two role mill until obtaining an average Mooney viscosity of ML (1+4)=22.75 and finally cured with a Bucher KHL 100 heating plated press. Useful surface treatment methods before curing can increase bond strength of cushion to carcass. With increase of accelerator efficiency curing time decreases and bond strength increases. Also by using an optimum blending condition, a high level of adhesion strength may be achieved.

By synthesizing a reactive hydrophobe on the basis of cyanuric chloride and applying it on cellulosic (cotton) fabric, the water absorption of the fabric is decreased. This hydrophobe substance which is synthesized from aniline and cyanuric chloride and it is called aniline dichlorotriazine (ADTC). This substance is able to react with cellulose like a reactive dye. A strong covalent bond between ADTC and cellulose chain in the fiber, leads to the blockage of hydroxyl groups and reduces the possibility of hydrogen bonding between the fibers and water. Hence, the possibility of transfer printing of treated fabric is facilitated. The relation between the printability of treated fabric with disperses dyes and the concentrations of the reactive hyrophobe are considered. Finally, by varying the inorganic/organic ratio for the treated fabric to the disperse dyes, the affinity of the dyes to cellulose is examined.

In this paper, the effect of high density polyethylene wax of Arak Petrochemical Complex, which serves as a binder in making ceramic cores by injection molding, has been .studied. The results showed that increase in the percentage of polyethylene in the mixture of powder-binder system, cause an increase in the mechanical strength of the cores. Noting that the porosity of the cores must be approximately 30%, therefore, in order to obtain this level of porosity it was found experimentally that the proper weight of the binder in the injection mix must be 37%.