Development and study of blended-base polymer composites

العناوين الأخرى

تطوير و دراسة متراكبات بوليمرية ذات أسس ممزوجة

مقدم أطروحة جامعية

al-Sadi, Awham Muhammad Hamid

الجامعة

الجامعة التكنولوجية

الكلية

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القسم الأكاديمي

قسم العلوم التطبيقية

دولة الجامعة

العراق

الدرجة العلمية

دكتوراه

تاريخ الدرجة العلمية

2006

الملخص الإنجليزي

This study has been conducted to investigate a theme that has a crucial interest in most industrial applications, it is the discipline of composites in general and polymer blends in particular.

In this investigation, the development of composite materials was achieved in two steps.

The first, by the hybridization of the resin matrix with different elastomers to prepare binary polymer blends, these blends have been synthesized by mixing either of (NBR, SBR and BR) with each of the (EP) and (UP).

The second step is reinforcement of the blended matrices with 30 % of two types of fibers.

The first was the E-glass fibers alone while the second was by utilizing a hybrid of E-glass fibers with Kevlar fibers (type-49).

Different weight percentages (5, 10, 15, ...., 50) % of those elastomers were mixed with each of EP and UP.

The optimum mixing ratios (OMR) of those blends have been selected depending on achieving acceptable macro miscibility, best adhesion between two phases and highest impact strength (I.S) of the resulting blends.

It was found that the values of (I.S) increased gradually with increasing of rubber content until its maximum value (OMR), and then it goes down as the percentage of the elastomer increases.

Based upon the above-mentioned criterion, five blends with (OMR) were prepared : EP / NBR(80 / 20) % , EP / BR(70 / 30)% , UP / NBR (90 / 10) %, UP / SBR (90 / 10) % , UP / BR (90 / 10) %, while (SBR-EP) was excluded due to the noticed phase separation at all ratios of mixing; then ,these blends were reinforced with single and hybrid fibers.

To give a complete description about the behavior of those blends and their composites under different stresses, some mechanical and physical tests were carried out.

The group of mechanical tests included : impact behavior tensile and pull-out characteristics compressive strength rebound hardness bending properties and young's modulus flexural strength and shear stress creep behavior On the other hand, the physical tests group comprised the determination of diffusion coefficient (D) of water, (0.5N HC1) and (0.5N NaOH) thermal conductivity (K) dielectric constant (er).

The results of this study proved that although the (I.S) of the blends has increased several times compared with that of EP and UP, the blends have maintained the general properties of their resin matrices.

This investigation also shows that the single and hybrid composites are recognized by their low density and high toughness.

The hybrid composites have showed higher (impact, tensile, Young's modulus and flexural) strengths but lower hardness and compressive strength compared with that of the single composites.

Creep behavior tests were showed that the creep rates (e) of blends will be dramatically decreased after the reinforcement with single and hybrid fibers.

The pull-out test results illustrate that both of the used fibers require more force to be pulled from EP compared with UP and also show Kevlar fibers have better adhesion to EP and UP compared with E-glass fibers.

The effect of water, HC1 and NaOH on the blends and composites has been investigated in this study and it is shown that water acts as a plasticizing agent for these materials, but alkaline solution has led to the degradation and deterioration of the (UP) blend, while acidic solution has no notable effect on the blends and composites.

The test results of thermal conductivity (K) and dielectric constant (er) show an increase in (K) for both blends and composites and slight decrease in (er) for blends but increase for composites.

التخصصات الرئيسية

الكيمياء

الموضوعات

• الخواص الفيزيائية
• الخواص الميكانيكية

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-305544