اثر نوع ماده پايه بر روي ميزان تقويت كنندگي نانو لوله هاي كربني: بررسي خواص مكانيكي كشش

Effect of Matrix Type on the Efficiency of Carbon Nanotubes as Reinforcement: Study of Tensile Properties

استفاده از نانولوله هاي كربن در پيشرفت علم و فناوري، به دليل خواص منحصر بفرد و بي نظير آنها، در سالهاي اخير بسيار مورد توجه قرار گرفته است. تحقيقات بسياري در زمينه ي تقويت پايه هاي پليمري توسط اين نانو ذرات انجام پذيرفته اما به تاثير نوع و پايه بر ميزان تقويت كنندگي آن كمتر توجه شده است. اين مقاله سعي دارد تا رابطه ي بين خواص پايه ي پليمري و نقش تقويت كنندگي نانو لوله هاي كربن را مورد بررسي قرار دهد. بدين منظور از سه نوع رزين پرمصرف صنعتي، يعني اپوكسي، وينيل استر و پلي استر استفاده گرديده و با افزودن 0/5% وزني از نانو لوله هاي كربني عامل دار نشده چند ديواره و تهيه ي نمونه هاي استاندارد كشش، اثر تقويت كنندگي آن تحت مطالعه قرار گرفته است. نتايج آزمايش عدم تغييرات محسوس مدوا الاستيسيته را براي دو رزين وينيل استر و پلي استر، و افزايش آن را براي اپوكسي نشان داده و براي استحكام كششي نيز در هر سه نوع رزين روندي كاهشي مشاهده شده است. به منظور تحليل بهتر مكانيزم هاي شكست تصاوير سطوح شكست نيز مورد بررسي قرار گرفته اند.

Multi-walled carbon nanotubes (MWNTs) have recently gained a great interest in science and technology due to their noble mechanical and electrical properties. These nano-particles with their huge aspect ratio, high strength and stiffness have become potential reinforcing constituents for common engineering polymers to achieve a material with good electrical conductivity and improved mechanical properties using only a few amounts of MWNTs. While different types of resins are available in the market, very little studies have been performed on the compatibility of different types of polymers and MWNTs. This study aims to understand the link between the nature of polymer as the base material for nanocomposite and reinforcement role of non-functionalized MWNTs. For this purpose, three common polymers, namely vinylester, polyester and epoxy were chosen, which are polymers with high industrial applications. Based on the mechanical properties and state of dispersion, 0.5 wt% of MWNTs was chosen to be used as amount of reinforcement for all three matrixes. Standard tensile specimens were prepared for both neat and reinforced resins, and were tested to obtain the nanocomposite elastic modulus and ultimate strength. The obtained results indicated that while for vinylester and polyester resins, there was no improvement in elastic modulus with addition of MWNTs, the ultimate strength of nanocomposites is less than that of neat resins. For epoxy resin, the ultimate strength decreased with addition of MWNTs, but elastic modulus increased by 5.6%. The trend of obtained results has been justified and discussed thoroughly using micromechanical properties which influence the mechanical behavior of pure polymers and nanocomposites. In addition, several pictures from fracture surfaces have been taken to evaluate the surface features and fracture mechanisms.