نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی دکتری، مهندسی نساجی و پلیمر، دانشگاه آزاد اسلامی واحد یزد، یزد

2 دانشیار، مهندسی نساجی و پلیمر، دانشگاه آزاد اسلامی واحد یزد، یزد

3 دانشیار، مهندسی و علم مواد، دانشگاه صنعتی خواجه نصیرالدین طوسی، تهران

10.22068/jstc.2019.104650.1521

چکیده

در این پژوهش، تأثیر تنش اعمالی بر تقدم، تأخر و نرخ پیشرفت واکنش های حلقوی سازی، اکسایش و هیدروژن زدایی در طی فرآیند پایدارسازی حرارتی الیاف پلی-اکریلونیتریل ویژه به‌منظور دستیابی به الیاف مقاوم به حرارت به‌عنوان تقویت کننده کامپوزیت های پلیمری مورد بررسی قرار گرفت. در این مطالعه، تنش مخصوص بر اساس تنش مخصوص آنتروپی بیشینه تعیین گردید. با کاربرد آزمون های حرارتی، شیمیایی، عنصری، تفرق اشعه ایکس، مشخصه یابی فیزیکی و مکانیکی، نرخ پیشرفت هر یک از واکنش های پایدارسازی به تفکیک شناسایی گردید. بر اساس نتایج به دست آمده، تنش اثر بازدارنده بر پیشرفت واکنش‌های پایدارسازی داشته و ضمناً رقابت بین وقوع حلقوی سازی و هیدروژن زدایی تحت تأثیر تنش اعمالی بسیار مشهود است. با افزایش تنش مخصوص، دمای شروع کاهش وزن ناشی از تخریب حرارتی، کاهش یافته است. این نتیجه بیانگر کاهش پایداری حرارتی نمونه ها با افزایش نرخ تنش مخصوص اعمالی در طی فرآیند پایدارسازی حرارتی است. با اعمال حداقل تنش مخصوص معادل cN/tex 0.6، بیشترین نرخ پیشرفت واکنش های پایدارسازی به‌ویژه حلقوی سازی گروه های نیتریل و ارتقای پایداری حرارتی الیاف پلی اکریلونیتریل اکسید شده جهت کاربرد در کامپوزیت های پلیمری مشاهده گردید.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Effect of stress on the of chemical reactions during special polyacrylonitrile fibers stabilization as a heat-resistant material in polymeric composites

نویسندگان [English]

  • Kosha Abbas Banaie 1
  • Mohammad Mirjalili 2
  • Reza Eslami-Farsani 3

1 Department of Textile and Polymer Engineering, Yazd Branch, Islamic Azad University, Yazd, Iran.

2 Department of Textile and Polymer Engineering, Yazd Branch, Islamic Azad University, Yazd, Iran.

3 Faculty of Materials Science and Engineering, K. N. Toosi University of Technology, Tehran, Iran.

چکیده [English]

In this research, the effect of imposed stress on the extent of progression of cyclization, oxidation and dehydrogenation reactions during thermal stabilization of polyacrylonitrile fibers as a heat-resistant material in the polymeric composites were investigated. In this study, specific stress was determined based on the maximum entropy stress value. The progress rate of each of the stabilization reactions was identified separately through the using of thermal, chemical, elemental, X-ray diffraction, physical and mechanical analysis. Based on the results, stress had a deterrent effect on the development of reactions and also the competition between cyclization and dehydrogenation occurring under the influence of stress is very evident. With increasing tension, the temperature of the lowering of the weight due to thermal degradation has decreased. This result showed that the thermal stability of the samples decreases with the increase of the specific stresses during the thermal stabilization process. By applying a minimum specific stress of 0.6 cN/tex, the highest rate of stabilization reaction, especially the nitrile group cyclization, and the thermal stability of the oxidized polyacrylonitrile fibers were observed for application in polymer composites.

کلیدواژه‌ها [English]

  • Polyacrylonitrile Fibers
  • Stabilization
  • Composite
  • Stress
  • Chemical reaction

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