الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The effect of addition of four different stabilizers from N
phenyl maleimide derivatives on the thermal stability of poly(vinyl chloride) (PVC) was
investigated. It is found that Para ethyl carboxy N-phenyl maleimide (PEC-NPMI) :1dditive is the
most effective ·stabilizer which improves the thermal· stability of pure PVC to a higher degree.
The effect of addition of PEC-NPMI, with different concentrations, on the physical properties of
PVC was studied. Thermogravim tri Analysis (TGA) in the temperature range from room
temperature up to 600 °C and at a heating rate of 10 °C/min was performed on the PVC samples
stabilized by different concentrations ofPEC-NPMI. Using the TGA and DTG thermo grams, values of
activation energy of decomposition were calculated. The results indicated that the
0.01 gmPEC-NPMJJl gmPVC concentration has the maximum
thermal stability and hence it could be suitable for dosimetric applications. Also the
results of the Differential Thermal Analysis (DTA) from room temperature up to 400 °C
at a heating rate of 10 °C/min showed that the O.Gl gmPEC NPMI/1 gmPVC sample has
the maximum value of melting temperature. The Infrared spectra measured in
the
wavenumber range (0-4000cm- 1
showed that the
concentration 0.01gmPEC-NPMI/1gmPVC has the maximum value of absorbance at different
wavenumbers. This property suggests that this sample is most suitable for applications
requiring PVC of high absorbance value in the IR region. On the other side, the ultravioiet
spectra in the wavelength range (200 - 400 nm) showed that the sample with 0.01 gmPEC
NPMI/1 gmPVC concentration has the minimun1 value of absorbance in the UV region.
Refractive index measurements were performed on solution samples of different PEC-NPMl
concentrations and the results showed that the PVC polymer sample stabilized by
O.OlgmPEC-NPMI/lgmPVC has the maximum isotropic nature and thus this sample might be a suitable candidate for dosimetric applications. The X-ray diffraction measurements showed that
the degre’=’ of ordering of the samples is dependent on_the PEC-NPMI concentration.
Since the sample with the concentration ofO.Ol gmPEC NPMI/1 gmPVC showed the maximum thermal
stability, maximum absorbance in the lR range and maximum isotropic nature, this sample was chosen
to be a subject for further study to investigate the effect of laser radiation on it aiming to
study the feasibility of further enhancement in its properties.
Samples from the O.OlgmPEC-NPMVlgmPVC concentration were exposed to infrared laser radiation with
energy fluences at levels between 0.95 and 8.53 J/cm2
’Thennogravimetric Analysis was performed on all irradiated samples and the values of the
activation energy of decomposition were calculated. The results showed that the thermal stability
of the 0.01 gm PEC-NPMI I 1 gm PVC sample is reduced by the action of laser. The results of
Differential Thermal Analysis (DTA) indicated that the irradiation with laser pulses up to 8.53
J/cm2 decreases the
melting temperature of the samples and this is most suitable for applications requiring molding of
thi.s polymer at lower temperatures. The results of the lR and UV spectra indicated that tlte PVC
polymer sample stabilized by 0.01gmPEC NPMI/1gmPVC and irradiated with 4.27 J/cm2 has the maximum
value of absorbance. This property suggests that this sample is most suitable for applications
requiring PVC of high absorbance value in the lR and UV regions. The refractive index of
irradiated samples showed an increase up to a
maximum value around 4.27 J/cm2 followed by a decrease on
increasing the laser energy fluence up to 8.53 J/cm2. The X-ray diffraction measurements showed
that the irradiation up to
4.27 J/cm2 leads to an increase in the disordering character of the samples, then increasing the
laser energy fluence up to
8.53 J/cm2 leads to an increase in the degree of ordering of the samples.
from the above study, one can draw the conclusion that this study can be used to introduce the
basis which may be used in constructing a simple sensor for laser radiation.
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