Document Type : Research Paper


Polymer Science and Technology Division, Research Institute of Petroleum Industry (RIPI), Tehran, Iran


The incorporation of several anti-rodent masterbatches into polyethylene (PE) granules used for gas pipes and the effects of the masterbatches on the physical properties of the pipes were studied. Four commercial anti-rodent masterbatches from different international companies including, Clariant, Alchemix, PolyOne, and Newgen were used in this research. Each of the masterbatch was primarily dry-blended with PE granules by a laboratory-scale tumbling mixer. The concentration of anti-rodent masterbatches used in the PE blends was fixed according to the recipe recommended by the producers as 1, 2.5, 3, and 4 phr for the masterbatches of Clarian, Alchemix, PolyOne, and Newgen respectively. PE granules and masterbatch blends were separately fed into the hopper of a pipe extruder and a length of a hundred and fifty meters of the pipe with the outside diameter (O.D.) of 25 millimeters was continuously produced for each anti-rodent-added PE compound. Two groups of experiments were planned for this investigation; laboratory experiments including impact resistance, tensile elongation, environmental stress cracking (ESCR), melt flow rate (MFR), and differential scanning calorimetry (DSC) were carried out on the control (anti-rodent free) and anti-rodent-added PE100 test samples prepared in the laboratory. Also, a group of factory tests such as burst, hydrostatic (100, 165, and 1000 hr), slow crack growth (SCG), and oxygen induction time (OIT) were performed on the control and anti-rodent-added pipe samples.


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