Investigation of particles distribution and matrix types for ᵧ and β irradiated lead polymer composites

العناوين الأخرى

دراسة التوزيع الجسيمي و أصناف الماتركس لمركبات البوليمر و الرصاص المشعة بأشعة كاما و بيتا

مقدم أطروحة جامعية

Husayn, Haydar Salim

مشرف أطروحة جامعية

Jafar, Harith Ibrahim
al-Bayati, Abd al-Husayn Abd al-Amir Mahmud

أعضاء اللجنة

Shafik, Shafik Sh.
Najim, Tariq Suhayl
Radi, Rad Abd al-Karim
Tawfiq, Nada Fadil
Majid, Kawakib Jasim

الجامعة

جامعة بغداد

الكلية

كلية العلوم

القسم الأكاديمي

قسم الفيزياء

دولة الجامعة

العراق

الدرجة العلمية

دكتوراه

تاريخ الدرجة العلمية

2011

الملخص الإنجليزي

The use of ionizing radiation for the synthesis and the modification of polymers have received more and more interest in the last years, due to it’s advantages in terms of both final properties of the material and environmentally sustainable process.

In the presence of air and at room temperature, it is necessary to solve different problems related to the radiation stability of polymeric articles and purposeful radiation-induced modifications of polymeric materials.

Gamma ray and Beta particles are used in this study to irradiate all samples for periods of (2, 4, 8, 12, 14 and 16) weeks, respectively with various doses.

The Instron Tensile tester (model 1122)isused to examine the feasibility of the effect of gamma and beta irradiation on some physical properties, (elongation at break and flexural strength).

A series of composites has been prepared by adding lead powder with different percentageweights to the Epoxy/Polyurethane blends.

The effect of gamma and beta irradiation on the flexural strength behavior of the points to a deterioration of the mechanical properties of composite due to the degradation and cross-linking reactions resulting from irradiation as examined.

Other samples of pure EP/PU blendsare irradiated for the same periods of time in order to study the effect of lead added on the flexure strength.

Changes in the color of samples are observed;the color varies from yellow to dark brown gradually as a result of different radiation doses used on the exposed composites samples.

When the sample is exposed to gamma or beta radiation for a longer time, the cross-linking process increases.

This work demonstrates that gamma and beta radiation could cause changes in the absorbance spectra of polymers.

Such changes of thermosetting polymers are studied by Fourier Transform Infrared Spectroscopy (FTIR) which is one of the favored techniqueto analyze the effect of ionizing radiation on polymer.

II FTIR analysis is performed using SHIMADZU-8400S spectrometer.The FTIR analysis indicates that high resistance to radiation is due to cross-linking in EP/PU blends.

Theoretical calculations for pure EP/PUblends and lead are used in this research,by Monte Carlo code in MATLAB-14.Studying the structure for one of these simulation codes is very helpful for obtaining a deeper knowledge of the various processes and the way they are related to each other.

The main physical processes associated with the transport of g-rays through matter are: coherent scattering, incoherent scattering, the photoelectric effect, and pair creation.

The effects of a gamma-ray beam passing through a medium are usually the result of many individual interactions because a photon can interact many times before it is absorbed or escaped from the medium.

For heavy elements, a lower photoelectric cross section is dominateddue to longer path lengths of the photons.

For light elements, like polymers, the dominant spectrum of the energy transferred to the polymer is around 0.7MeV.

For polymer, g-ray deposits energy either by photoelectric absorption or by Compton scattering, but for lead the dominant deposited energy is by pair creation.The predominate interaction of the primary g-ray with the medium of EP/PU blends is either by photoelectric absorption or by Compton scattering, with probabilities proportional to the corresponding cross sections

التخصصات الرئيسية

الفيزياء

عدد الصفحات

130

قائمة المحتويات

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-606294