الفهرس 
Introduction and surveyOnly 14 pages are availabe for public view
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Abstract
The present work was engaged in the preparation and characterization of some acrylate based terpolymers through bulk polymerization in presence and absence of silicate based fillers, Cloisite 20A and Bentonite 34, to obtain polymer silicate composites suitable as insulator for electric cables. Monomers of Butyl acrylate (BA), Methylmethacrylate (MMA), Acrylic acid (AA) and Acrylamide (AAm) were employed at different compositions and ratios.
Structural, physicochemical, mechanical and electrical characterization of the polymer composites were conducted, evaluated and compared to specific standards of electric cable insulation.
1- Weight average molecular weight (Mw), number average molecular weight (Mn), poly dispersity (PD) of the prepared polymers and their composites measurements; determined by gel permeations chromatography (GPC); concluded the following:
• Both Mw and Mn in addition to the PD for all the polymer composites were noticeably improved due to a regularity function proposed by the presence of Cloisite 20 A or Bentonite 34. Cloisite 20 A or Bentonite 34 presented the same role through the polymerization process that affect the propagation step which reflects, in turn, on both the molecular weight parameters and the degree of dispersity of polymer.
• While acrylamide allowed more ordered polymer product, acrylic acid aided the production of higher polymer molecular weight.
2- Fourier Transform Infra Red (FT-IR) and proton nuclear magnetic resonance (1HNMR) investigations of the prepared polymers and their composites confirmed the chemical structure constitution and the respective indicative groups.
3- Thermal stability studies (TGA) of the prepared polymers and their composites concluded that Bentonite fillers enhance the thermal stability of all prepared polymers at the earlier stage of decomposition especially with 10 wt. % from bentonite, but in the final stage of decomposition there is no observation for an advantageous effect of bentonite on the degradation of the prepared polymers which indicate an absence of bentonite intrusion or conjugation to the chemical structure of either polymer in the composite.
4- Micro structure of the prepared polymers and their composites were studied using X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM).The results showed clearly an intercalated structure in presence of the bentonite fillers which implies that the monomers had polymerized within the bentonite laminar forming inorganic-organic hybrid.
5- The tensile strength, elongation at break and shore hardness (D) of the prepared polymers and their composites were measured and evaluated. The results disclosed that, Cloisite 20A and Bentonite 34 have influenced the mechanical properties at low filler concentrations which are explained as due to good dispersion of the filler in the polymeric matrix and the electrostatic attractions effect between polymer chains functional groups and the surface of the silicate layers. High filler concentration, however, exhibited ill dispersion and eagerness to solid particles agglomeration instead. Shore hardness measurements, however, did not prove any noticeable role for the bentonite fillers.
6- Volume resistivity and electric capacity measurements of the prepared polymers and their composites indicated that the addition of Cloisite 20A or Bentonite 34 to the prepared polymers had improved its volume resistivity and electric capacity properties that is increased by further addition of the bentonite filling materials. This behavior may be attributed to the effect of bentonite fillers on the space charge accumulation within the polymeric matrix.
7- Addition of bentonite fillers within the polymeric matrix did prove its positive influence on density; melt flow and oxygen index parameters of the composites prepared.
8- Study of the effect of thermal ageing and sun radiation is considered an important relevance to electric cables quality and durability against weathering conditions. Upon exposing the prepared polymer composite samples to excessive heat and sun radiation, re-measuring characteristic indicative parameters were found enhanced positively indicating solid support to the choice of the bentonite fillers employed, namely, Cloisite 20A and Bentonite 34.