نشریه صنعت لاستیک ایران
پیاپی 92 (زمستان 1397)

Nano- composite compounds based on natural rubber and styrene butadiene (NR /SBR) combined different percentages as 4/5, 5 and 6/5 phr Nano clay were prepared. Effects of Nano clay composition on the mechanical and dynamical properties, morphology and rheological properties were studied. Rheometer test was used to determine the curing time (t90) and safety time (t5), study the morphology and rheological behavior of the Nano composite compounds. Results obtained from rheometer test showed that with increasing the amount of Nano clay particles curing time and the safety time of the compound are reduced. This decline for NR/SBR is as much as 40% percentages. This effect according to the modified ammonium phosphate nanoparticles as well as are justified and expressed. The phosphate compound in the curing reaction participates and has accelerated role. The results of the tensile test showed that opening stretch layers of silica and diffusion chain polymer into theme. The test results show that adding 5 phr nanoparticles compound modulus in NR/SBR has a twice increasing. As the information nanoparticles used is the fully unlocked. Tensile test, increased elastic modulus and viscosity with increasing clay nanoparticles showed. This can be due to the higher surface area and better interaction with clay nanoparticles and the matrix substrate attributed crosslinking density. As well as other mechanical properties such as compression set and hardness tests show that the nanoparticles due to their high surface area polymer have very good interaction with together. Increase in compression set testing about 50% in NR/SBR combination was observed. The hardness test was observed with increase nanoparticles in the first increases the hardness and then decreased. Nano-Composite construction by XRD tests were approved, in NR/ SBR combination no peak was observed in samples of 2 thetas. In this work, in accordance we can remove 40 phr Carbon black. That substance in terms of environmental pollutions by constructing of Nano composites was only 5 phr adding Nano particles to a polymer system also saw a significant increase in anti- tear properties in tire. In addition the mechanical properties of Nano composites are increased.

Modification of the polymers through blending has an important role in formulating of the products final properties. Blending of nitrile rubbers (NBR) with poly vinyl chloride (PVC) introduces vinyl based thermoplastic elastomers that are used in a wide range of the industrial application. Addition of the thermoplastic matrix to NBR leads to improvement of the mechanical parameters of the sample, such that, the tensile strength with addition of 70 phr PVC to NBR increases from 3.5 to 9.5 MPa. Dynamic vulcanization is one the effective factor on enhancement of mechanical parameters of PVC/NBR blend. Comparison of two blends containing 10% rubber phase shows that dynamic vulcanization leads to an increase of 205% in the Young’s modulus and increase of tensile strength from 7.7 to 14.8 MPa and for blends with 30% NBR, leads to a 370% increase in tear strength. In addition to, aging of the blends enhances the tensile and tear strength, modulus and hardness that are related to microstructure changes due to keeping in higher temperature. Also, compatibilizing agents with creation of interfacial adhesion between two phases have an effective role on the mechanical properties and reduction of blends weight loss. Addition of 4% Glycidyl Methacrylate to the blend containing 20% PVC leads to reduction of 5% in the total weight loss. Furthermore, increment of NBR also leads to increase of thermal stability of blend. Study of blend morphology shows that with the increase of NBR amount of the unvulcanized system, particles coalescence is occurred and particle size would be larger. In contrast, increase of NBR amount in the vulcanized system leads to more curing degree and reduction of NBR particles size. Phase morphology with smaller particles size results in the improvement of mechanical properties.

Nowadays, due to too much focus on the development and market complexity and economic constraints, optimal use of available resources and knowledge to create value activities for customers and to timely response to the demands of customers in different market segments is the activity has become inevitable and has forced organizations by eliminating the traditional structures and working methods, by increasing the level of customer satisfaction, maintain its share in market. These factors make the move organizations toward lean manufacturing. Value stream mapping is a tool for improving quality and implementation of Lean Manufacturing base, is very important and basic that as one of the most common methods of analysis systems for detect and remove different wastes to be used in operating activities and support. In this study, production status a manufacturing company by using value stream mapping and change the status of production planning has been guided towards lean manufacturing and results of employing Value stream mapping methods by ARENA software is simulated. Results of this study represents is impact of the application of this method in improving the key indicators of industrial production the studied.

Providing an effective maintenance management system for machinery and equipment of a manufacturing company has great impact on the productivity of a firm. While, without usage of qualified and skilled repair technicians operating an effective maintenance system will be very difficult. Hence, the main aim of this paper is to determine the number of required technical staffs for conducting the maintenance tasks as pilot in the baking hall of the 4th zone of the Barez tire industry group. For this purpose, based on the interview that has been done with maintenance manager of the 4th zone, financial manager and technical manager of the complex, several criteria and alternatives have been determined for determining the number of the required technicians in this section. On the other hand, the minimum number of required technicians for this section was calculated based on the archived data in 2017 from maintenance department and the results showed a minimum six staffs in this section. Finally, by using Group Fuzzy TOPSIS method, the required technician for working on 32 baking machines in the 4th zone for both electrical and mechanical tasks should be seven persons.

In today's world, organizations need to reduce their costs and improve their productivity to survive. An effort that can be made to increase productivity is the performance of supply chain management. Sustainability in the supply chain, which takes into account the serious environmental challenges, prevents the production of any kind of pollution from human life by producing green products. The main purpose of this paper is to provide a Multi-Stage Data Envelopment Model to Assess the Sustainable Supply Chain Network of Rubber Producing Companies. The methodology of this research is analytical-descriptive and in terms of purpose is applied. One of the techniques that can be used to evaluate the performance of a stable supplier is data envelopment analysis. The research community in this study is 10 rubber companies whose performance has been evaluated over the past three years in 2013, 2014 and 2015. Based on the results, in 2013, Simorgh and Pars tires were ranked one, in 2014, Barez Tire and Pars Rubber ranked one, and in 2015, Barez Tire, Kavir Tire, Pars Tire and Iran Tire ranked one.

Given the importance of finding the supply chain for many companies in recent years and turning it into one of the competitive advantages, the continuous and effective communication with suppliers as the upstream segment can play a crucial role in the strength and balance of this chain/ In the supply chain, an important component of production and logistics management is the choice of the supplier/ Mistake in choosing a supplier can lead to a shaky financial and operational position of a company/ On the other hand, the correct supplier selection can reduce the cost of purchasing, market competitiveness, and improve end-user satisfaction/ This research seeks to evaluate and select suppliers and introduce a superior supplier for Yazd rubber industry/ To this end, the combination of two QFD and fuzzy VIKOR techniques has been used/ Since there are criteria in the selection of the supplier of both quantitative and qualitative aspects that sometimes contradict each other/ Therefore, the decision in conditions of uncertainty is more in group and ambiguous; fuzzy numbers have been used to solve this problem/ The present study is in applied research/ In this research, an non probable and purposeful study of industrial and academic experts has been made/ Important suppliers' indicators, including experience and credibility, price, flexibility in customer orders, supplier access and geographic location, valid certificates and licensed quality, and validated environmental permits for products/ Important product features include technical features, safety tabs, test reports, environmental effects, packaging and after sales services/ The weight of each index is determined by the fuzzy QFD method, and finally the suppliers of Yazd rubber industries are ranked using fuzzy VIKOR method.