دانلود مقاله ترجمه شده خواص سطحی و چسبندگی بین سطحی فیبر آرامید اصلاح شده – مجله الزویر

فهرست مطالب:

چکیده
مقدمه
آزمایش
مواد
تیمار های پلاسما
تست های کشش فیبر
میکروسکوپ الکترونی نگاره(اسکن کننده)
طیف سنج الکترونی برای تجزیه تحلیل های شیمیایی
طیف سنج الکترونی برای تجزیه تحلیل های شیمیایی
تست و تهیه نمونه میکروباند
نتایج بحث
ناهمواری سطحی فیبر
تجزیه تحلیل های ESCA در سطح فیبر
آنالیزهای SSIMS سطح فیبر
مقاومت برشی بین وجهی کامپوزیت های آرامید-فیبر/رزین اپوکسی
آزمایش سطح شکست نمونه های میکروباند
نتیجه گیری

بخشی از ترجمه:

تیمار گاز پلاسما یک روش سریع و کارامد برای اصلاح سطح فیبر کولار ۴۹ و بهبود  ادهیسیون بین رزین اپوکسی است. بعد از تیمارهای پلاسما، کاهش در مقاومت کششی کم تر از ۱۰ درصد است.  SEM,  ESCA  وSSIMS  برای توصیف تغییرات در خواص سطحی فیبر ناشی از  تیمار پلاسما مورد استفاده قرار گرفتند. خارج کردن لایه اکسید ساکن از سطوح فیبر و وارد کردن  گونه های فعال به سطح فیبر  به طور همزمان طی تخلیه پلاسما بسیار مهم است. گروه های جدیدا ایجاد شده عاملی هیدروکسیل و کربوکسیل را می توان توسط  طیف های منفی SSIMS  شناسایی کرد. بهبود قابل توجه در IFSS  رزین اپوکسی فیبر کولار ۴۹ ناشی از پیوند کوالان ایجاد شده  بین  گونه های فعال  در سطوح اصلاح شده فیبر و اپوکسید های رزین می باشد. بهبود IFSS  با تغییراتی در سطح رخ و شکست در رزین اپوکسی همراه است.

بخشی از مقاله انگلیسی:

۱ INTRODUCTION Aramid fibres have a unique combination of stiffness, high strength and low density that rivals the properties of inorganic reinforcing fibres such as glass and carbon fibres) However, the off-axis properties of aramid composites are limited by low fibre/matrix adhesion by comparison with that of inorganic-fibre-reinforced composites. 2 In order to improve the fibre/matrix interfacial bond, a variety of fibre surface modifications, such as plasma treatments 3-6 and chemical modifications, 7-1° have been developed. Among others, plasma treatment has an important advantage in comparison with other methods, which is that the surface modification can be achieved with the minimum alteration of the bulk characteristics of the substrate polymer. 11 Excluding our previous studies, 5’6’9 a combination of ESCA (electron spectroscopy for chemical analysis) and SSlMS (static secondary ion mass spectroscopy) to elucidate the adhesive behaviours has never been reported, although aramid fibre modifications have been studied by several workers. 3’4’7″s In the present study, Kevlar 49 fibres were modified by NH3, 02 or H20 plasmas, in order to improve the adhesion to epoxy resin. The microbond pull-out technique was then used to measure the interracial shear strength between the fibre and epoxy resin. The chemical compositions and functional groups on the fibre surfaces were quantitatively and qualitatively analysed by ESCA and SSIMS, respectively. Both the surface topography of the treated fibres and the fracture surfaces of microbond pulled-out specimens were examined by SEM (scanning electron microscopy). The effect of plasma treatment on the fibre strength was also investigated. 2 EXPERIMENTAL 2.1 Materials Kevlar 49 fibres (1420 denier) made from poly(pphenylene terephthalamide) (PPTA) were supplied by the Du Pont Company. The epoxy resin was Epon 828 and the curing agent was 4,4′- diaminodiphenylmethane (DDM), which were supplied by the Shell Chemical Co. and Merck, respectively. Anhydrous ammonia (99.99%), oxygen gas (99.99%), and distilled water were used for plasma treatments. 2.2 Plasma treatments The fibres were cleaned successively with 1,2- dichloroethane, methanol, and de-ionized water, followed by drying overnight at 110°C in a vacuum oven before plasma treatments. Some of the cleaned fibres without plasma treatment served as ‘control’ samples. 490 G. S. Sheu, S. S. Shyu The plasma treatments were carried out in a SAMCO Model BP-1 bell jar plasma reactor. The gases used for plasma treatments were ammonia, oxygen and water vapour. After evacuating to a pressure lower than -0.1 Pa, the reactor was purged with each gas three times and then the pressure was maintained at -20Pa throughout the plasma treatment processes. The fibres were treated at 30 W of radio frequency (13.56 MHz) plasma power in each gas plasma environment for 15s-10min treatment time. At the end of each treatment, the plasma power was turned off and the treated fibre was left there for 30 min post-treatment. 2.3 Fibre tensile tests Tensile tests of Kevlar 49 fibres were performed by using the modified ASTM D3379-75 (1982)procedure. A gauge length of 10mm at a crosshead speed of 1 mm/min was used to test the fibres. Altogether 40 single filament specimens were tested for each treated sample. 2.4 Scanning electron microscopy The surface topography of the plasma-treated and control fibres were observed by scanning electron microscopy (SEM). Micrographs of single filaments were used to determine the fibre diameter. The filament diameter was the average of more than 60 measurements from SEM micrographs. The fracture surfaces of the fibres pulled-out from the resin droplets were also examined by SEM. 2.5 Electron spectroscopy for chemical analysis A Perkin-Elmer PHI590 SAM/ESCA instrument was used for ESCA measurements. The spectra were collected using a MgK~ (hv = 1253.6 eV) X-ray source (12 keV) operated at 250 W and at a pressure below 5 x 10 -s Pa. High-resolution spectra were obtained at a pass energy of 25 eV. The atomic sensitivity factors (ASF) for core levels were used to calculate the atomic concentration of the fibre surfaces. 2.6 Static secondary ion mass spectroscopy The SSIMS experiments were performed by using a Cameca IMS-4f ion microscope equipped with a Cs ÷ ion source and magnetic sector mass analyzer. The primary ion source was 10keVCs ÷ operated at a current of 10pA and at a pressure lower than 1.5 × ۱۰ -۹ Pa. An electron flood gun set at 4.5 keV was used to minimize sample charging. 2.7 Microbond specimen preparation and test The Epon 828 epoxy and DDM were mixed in 4:1 weight ratio to make small droplets on Kevlar 49 fibres. After curing the resin, then measuring the length of the resin droplets by an optical microscope, microbond specimens were tested at 25°C on an Instron tester (Model 4302) at a crosshead speed of 0-5mm/min. Details have been described in a previous study.