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Abstract
In this study, resorcinol, pyrogallol, are polyrnerized by using the method developed by Elgarfs method.
Polyresorcinol (PRE) and polupyrogallol (PPY) were used as UV stabilizer for polyethylene (PE) produced from Sidi kerir petrochemical company (Sidpec). This company uses exported chimassorb (Ciba) as UV stabilizer. A comparative study of the efficiency of PRE, PPY from one side and chimassorb on the other side as UV stabilizers are done. Before introduction of the compound to weathering ometer, the results show that when 0.25% anti oxidant (Irganoxe) —which is used with chimassorb- was used in our compounds with the same concentration, the percent elongation at break is not affected. In other words the addition of anti oxidant has no effect on the compound.
By using 0.06%chimassorb with anti oxidant the percent elongation at break is 1239% while it decreases by 55.6%, when using 0.06%PPY with anti oxidant or 0.03%PPY without anti oxidant. This means that the decrease of initial value of percent elongation at break of the compound containing PPY either with 0.03% or 0.06% is the same, regardless of the use of anti oxidant or not. This may be due to partial cross linking of PE with OH groups present in
PPY.
By using 0.06%chimassorb with anti oxidant the percent elongation at break is 1239% while it decreases by 8.3%, when 0.06%PRE is used -under the same condition- when 0.03%PRE without anti oxidant, the percent elongation at break is decreased by 14.6%, from that of chimassorb. These differences of the value of the percent elongation at break for the cases of 0.03% and 0.06%PRE may be due to the increase of OH group due to the increase of concentration giving more probability for partial cross linking with PE, which leads to smaller decrease on the percent elongation at break in the case of 0.06%PRE.
Generally the compounds of (PE+PRE) and (PE+PPY) is accompanied by the decrease in percent elongation not due to degradation as confirmed by DTA study but may be due to partial cross linking of OH groups present in PRE and PPY, this is confirmed by the presence of a peak at 2853 cm’ indicating C-H aliphatic in FTIR. This decrease of initial percent elongation at break of the compounds before introducing to the weathering ometer is itself an advantage because this gives by this way dimensional stability of the compounds.
After introducing of the compound to weathering ometer. For a time 150 hr, with using the same concentration of anti oxidant. The decrease of percent elongation at break for 0.06% chimassorb(Ciba) is decreased by 12% but when we used 0.06%PRE the percent elongation at break are decreased by 3. 8% while when we decrease the concentration of PRE to 0.03% without anti oxidant, the percent elongation at break are decreased by 2%. This decrease still lower than the case of chimassorb (12%), this means that we can omit anti oxidant and decrease the concentration of PRE to the half of chimassorb and this decrease make the process more economic. In case of adding PPY by 0.06% with anti oxidant the percent elongation at break are decreased by 9%. This means that the efficiency of PPY is higher than that of chimassorb