نشریه صنعت لاستیک ایران
پیاپی 72 (زمستان 1392)

In recent years polymer blends due to the technological importance for achieving the desired material is provided fascinating field for research and industrial activities. Extensive growth of polymer blends especially rubber blends are due to achieving a variety of benefits, including control of processing and production costs. This research is focused on the migration of additives include fillers and vulcanization agents in rubber blends. In this context, the factors affecting the migration of traditional fillers such as carbon black, silica and calcium carbonate as well as migration of vulcanization agents between the phases are discussed. Mechanism for the transfer and migration of additives and also the importance of migration phenomenon and controlling of migration in rubber blends is discussed. Changes in mechanical properties due to the migration of fillers and vulcanization agents in rubber blends reviewed and strategies for controlling the migration of these materials are presented. In this research covulcanization in rubber blends as a key factor in the migration phenomenon has also been considered. Crosslink network formation at the interface is one of the most essential items to improve the mechanical properties of the product. Crosslink formation at the interface is only possible when curing rate is the same on both rubbers. Viscosity difference between components can be effect on the distribution of additives in the blend. Fillers tend to migrate to the lower viscosity phase in the blend. For less than the critical amount of filler, the filler is distributed only in the phase with lower viscosity. In filled rubber blends, polymers with lower viscosity will accommodate more filler content. This paper presents examples of the phenomenon of migration in different rubber blends including special purpose elastomers and general purpose elastomers will give a new perspective for researchers and industrialists.

In this research a new eco-friendly nanocomposite material has been synthesized from natural rubber and magnetite nanoparticles. The poor oil resistance of natural rubber in the nanocomposites is exploited for the absorption of oil spills in sea. For this purpose, partially epoxidized natural rubber (ENR)/magnetite nanoparticle (MN) nanocomposites are prepared and the amount of crude oil absorption by them is studied. The extent of epoxidation is controlled in such a manner that the NR does not lose its elasticity while retaining to a significant degree its oil absorbing property. Epoxidation also serves as a means for binding sufficient quantity of MNs so that the composite can be recovered using a magnetic field. ENR with 5 mol% of epoxidation served as the best oil absorbent among all the absorbents studied as it was stable in crude oil even after many days of immersion. It is observed that each gram of ENR-MN nanocomposite absorbs 7 g of crude oil without any mass loss. The material was reused for several cycles without much loss in the capacity. The crude oil uptake of ENR-MN is greater than that of butyl rubber which is the most commercially used rubber for oil removal. Porous rubber was also synthesized for the first time as oil uptake is facilitated not only by the hydrophobicity but also by the capillary absorption. Porous ENR absorbed a relatively larger amount of oil and exhibited the highest stability. All the sorbents studied in this work have quite high absorption capacities to be applied practically with a very low water uptake and a few of the absorbents could be satisfactorily reused.

The NR/BR blend compound formulations for tire sidewall applications contain a set of stabilizers added to prevent degradation mainly due to oxygen, ozone, and heat. 6PPD is the most effective and widely used antiozonant in tire compounds, but is a highly staining material causing a surface discoloration of the tire sidewall. Incorporation of 30 phr EPDM into blends of NR/BR improves the ozone resistance to the required level, without the need of 6PPD. The first two parts of this series have described a reactive processing technique applied to enhance the covulcanization and blend homogeneity, together with their characterization. In the present article, the properties of the NR/BR/EPDM blends prepared by both reactive and straight mixing are tested in comparison with those of equivalent conventional NR/BR compounds. The reactive NR/BR/EPDM blend vulcanizates show excellent tensile strength, elongation at break, tear strength, fatigue-to-failure, and ozone resistance in both static and dynamic conditions. The properties are equivalent or even superior to those of the conventional NR/BR tire sidewall compounds. The simple straight mixed NR/BR/EPDMblend vulcanizates distinctively possess inferior mechanicalproperties compared to those of the reactive mix.

Selecting the appropriate strategies is complex and risky, because each strategy, direct organization toward a competitive environment and determines how administrators plan to implement organizational strengths and weaknesses, opportunities and threats to the. Always selecting the most important strategies that is valuable to allocate resources is administrators principal challenge. This study is aimed Of selecting competitive marketing strategy between the three differentiation, Concentration and leadership strategy in cost reduction for Azarbatri company and Was conducted by descriptive manner. In this research, initially five decision criteria for Azarbatri company were identified using the resources-based view (RBV) including the Management capabilities, customer relationship capabilities, market innovation capabilities, human resource assets and credit assets. Then questionnaires were distributed in Azarbatri company, calculated data were analyzed using the Super Decision software and, the highest priority is selected between the competitive marketing strategies (differentiation, Concentration and leadership strategies in cost reduction) for the company by analysis network process (ANP) and the results indicate that the highest priority for Azarbatri company is leadership strategy in cost reduction.

One of the important factors of growth and development in a society or a firm is the productivity factor. Failure to understand the important role of productivity and low productivity caused to third world or developing countries, do not have much success in the development process. However, productivity can solve many problems in Third World countries (including inflation, unemployment, etc.). The importance of productivity and its important role in our lives is undeniable. Today, about productivity and improvement strategies new ideas and theories are presented. In this paper, first we review the concept of productivity and its importance and necessity.Then the productivity process and cycle and one of the main factors in the productivity cycle (productivity Improvement) will be further investigated. In addition to old ways of improving productivity, new strategies that various researchers have presented, will be discussed.

Due to the high intensity of competition in most industries, companies are in need of Marketing Research. One of the new tools in order to identify competitors and competitors analysis are competitive intelligence.Competitive intelligence as tool in order to analysis of internal and external environment and use to attain valuable information about competitors and then usage this information for correct planning and benchmarking. In this article originally mentioned to the definitions of marketing intelligence and then expressed, definitions and purposes of competitive intelligence, afterwards mentioned to the competitive intelligence proceses and different attitudes towards competitive intelligence. In the conclusion researcher mentioned to the requirements of competitive intelligence system and finally, the results of competitive intelligence systems has been pointed out, which can be useful for Iranian companies managers.