نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشجوی کارشناسی ارشد، مهندسی کامپوزیت، دانشگاه صنعتی مالک اشتر، تهران، ایران

2 دانشیار، مهندسی کامپوزیت، دانشگاه صنعتی مالک اشتر، تهران، ایران

چکیده

معمولا با افزایش دما، پخت اپوکسی کامل‌تر انجام می‌شود و مدول و استحکام کششی نیز افزایش می‌یابد اما به‌دلیل اتصالات عرضی زیاد، پلیمر ترد شده و چقرمگی شکست آن کاهش می‌یابد. در این پژوهش، به‌منظور افزایش چقرمگی شکست، از تکنیک کاهش دمای پخت استفاده شده و نانوذرات سیلیکا در اندازه‌های مختلف، برای جلوگیری از کاهش استحکام به اپوکسی اضافه شد. به‌منظور مطالعه اثر دما، نمونه‌های اپوکسی با کسر حجمی‌های مختلف از نانوذرات سیلیکا، در دو دمای پخت 105 و C°90 تهیه شده و میزان چقرمگی شکست، استحکام و مدول کششی آن‌ها توسط آزمون‌های مکانیکی اندازه‌گیری شد. در نمونه‌های فاقد نانوذرات، با کاهش دمای پخت، افزایش قابل توجه در چقرمگی شکست مشاهده شد اما مدول کششی و استحکام نمونه، به‌دلیل پخت ناقص اپوکسی، کاهش یافت. اما در نمونه‌های حاوی نانوذرات سیلیکا، تقویت‌کنندگی نانوذرات بر نقص پخت غلبه کرده و برآیند دو مکانیزم موجب افزایش استحکام و مدول کششی شد. در عین حال افزایش چقرمگی و انرژی شکست، نشان از هم‌افزایی قابل قبول تکنیک‌های پخت ناقص و حضور نانوذرات سیلیکا در کامپوزیت، دارد. هر چند چقرمگی شکست نمونه‌های پخت شده در دمای C°90 همواره از نمونه‌های پخت شده در دمای C°105 بیشتر است اما با افزایش سطح نانوذرات سیلیکا (کاهش اندازه نانوذرات) نقش نانوذرات غالب بوده و تفاوت متأثر از دمای پخت کمتر می‌شود. محاسبات نشان داد مکانیزم‌های تغییر شکل پلاستیک، گسترش حباب و شکسته‌شدن کلوخه‌ها، نقش اصلی را در افزایش چقرمگی شکست داشته و تحت تاثیر یکدیگر تشدید می‌شوند.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

The effect of curing temperature on fracture energy of nanosilica filled epoxy with different particle sizes

نویسندگان [English]

  • Seyed Reza Akherati 1
  • Mehrzad Mortezaei 2
  • Iraj Amiri Amraei 2

1 Department of Composite Engineering, Malik Ashtar University of Technology, Tehran, Iran

2 Department of Composite Engineering, Malik Ashtar University of Technology, Tehran, Iran

چکیده [English]

Epoxy toughening is very important in industry, because high brittleness and low fracture energy. In this work different toughening techniques was used for epoxy curing system. The techniques include change of the curing temperature and simultaneous addition of silica nanoparticles on curing system. The glass transition temperature of epoxy with this curing system is approximately 118 , if the curing temperature is too closer to glass transition temperature then curing is complete, So tensile modulus and other properties such as strength is increased; In this work curing temperature was changed from 105  to 90 . While it was just pure epoxy to be tested, tensile modulus decrease and fracture energy increases, as result imperfect curing at 90 . But addition of nano-particles to the curing system increased tensile modulus in both temperatures curing system, this increased in both curing system is equal while the equal nominal surface of the nanoparticles used. On the other hand toughness and fracture energy in both curing system increased with increased nominal surface of nanoparticles when nanosilica is used, this raise in the fracture toughness at curing temperature of 90  is always greater than from the fracture toughness at curing temperature of 105 . In generally seen curing at 90 and increase in the nominal surface of nano- particles which were strongly increased fracture toughness, and modulus. The fundamental mechanisms that are effective in increasing the toughness of nano composites, they are used to analyzing the increase in fracture toughness of nanocomposites.

کلیدواژه‌ها [English]

  • epoxy
  • Nano-silica particles
  • Tensile modulus
  • Fracture toughness
  • Curing temperature

 

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