![]() ![]() This chapter will give an overview of the importance of XLPE and its products various existing methods of crosslinking in PE suggest the appropriate crosslinking method for a specific application, the impact of crosslinking on the various grade of PE, patents in crosslinking techniques of PE and remedies for strengthening the weakness of XLPE products. In addition to the defects in XLPE materials, the smaller number of recycling techniques and heavy disposal of XLPE wastes are the main environmental alarm today. A new technique called click chemistry is also used to introduce crosslinks in PE, which have a smaller amount of hazards than the traditional techniques. and also introduce crosslinks in PE with the new technique-click chemistry. Tuning the properties in XLPE material for desired applications can be obtained by different crosslinking methods like radiation, peroxide, silane, azo, etc. The superior physicochemical properties made XLPE obtain the major share of the plastic market in both developed and developing countries. ![]() The data presented will include multiple temperatures and stresses along with failure mode analysis for each resin.Crosslinking in thermoplastic polyethylene (PE) converts it into thermoset crosslinked polyethylene (XLPE or PEX). The methodology used to prepare the samples is critical to successful PENT testing of PEX materials and this will be discussed. This paper will present PENT data for PEX pipe resins. However, there is little slow crack growth data available for PEX materials in a form that can be directly related to other materials. Most PEX standards include some sort of notched pipe test to demonstrate adequate resistance to crack propagation when a defect (notch) is present. In general, the three common methods of crosslinking, peroxide, silane grafted, and radiation, are treated equally in the standards with regard to physical and mechanical properties. PEX materials are generally believed to have very good slow crack growth properties and some would argue that they are immune to slow crack growth. This study reports PENT data for PEX pipe resins, which allows a more direct comparison of the slow crack growth properties of crosslinked PE pipe grades with standard PE pipe grades.Ĭrosslinked Polyethylene (PEX) pipe and tube are being used globally for potable water plumbing systems, industrial piping systems, radiant heating systems, etc., successfully. Unfortunately the methods used to measure the slow crack growth resistance of PEX are different than those used for standard polyethylene (PE) pipe grades. ![]() Crosslinked polyethylene (PEX) is known to have very high slow crack growth resistance as a result of crosslinking. Failure time has increased from a few hundred hours to over 50,000 hours in some cases. Results are reported as hours to failure. ![]() The most common test method for pipe products is ASTM F1473, Standard test Method for Notch Tensile Test to measure the resistance to Slow Crack Growth of Polyethylene Pipes and Resins (PENT). The performance of HDPE resins with regards to slow crack growth has increased dramatically over the past two decades. ![]()
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