Eagle Layout Editor 4.11 Ware. Environmental Stress Cracking Resistance of Polyethylene » » Environmental Stress Cracking Resistance of Polyethylene Environmental Stress Cracking Resistance of Polyethylene © Grayline LLC, 2017 One of the most common causes of failure for polyethylene components is environmental stress cracking (ESC), a form of low-stress failure that is accelerated by environmental interaction. Surface active chemicals such as those commonly found in detergents are considered an environmental effect that may accelerate failure, while environmental stress cracking resistance (ESCR) is a plastic material’s resistance against it.

Environmental Stress Crack Resistance Of Polyethylene Introduction to Environmental Stress Cracking and ESCR Over the past decade, high-density polyethylene (HDPE.

The following is a discussion of the theory behind this phenomenon as well as experimental results obtained from testing four different types of ethylene-based plastics. It was found that hexene-branched linear-low density polyethylene (h- LLDPE) and crosslinked polyethylene (XLPE) far outperformed butene-branched linear-low density polyethylene (b-LLDPE) and low-density polyethylene (LDPE). INTRODUCTION The expansion of the plastic industry in recent decades has made possible the utilization of plastic parts in new and demanding applications in which long life-time service is an essential component.

For instance, plastics are being used extensively in fluid flow applications, such as piping for gas distribution and tubing for water transfer [1]. Replacing metals with plastics has made it necessary to use plastics that are mechanically robust and can withstand demanding conditions. Materials that exhibit such required properties as high impact strength, high stiffness, or high tensile strength, however, often suffer from one of the most common forms of failure – low-stress crack rupture. The addition of a surface-active chemical, an environmental effect, accelerates this type of failure, thus this mechanism is termed environmental stress cracking (ESC). A material’s resistance against this type of failure is called environmental stress cracking resistance (ESCR). The ESCR of polyethylene, one of the most widely used plastic materials, is of particular concern in the plastics industry and is the subject of this investigation. Polymer Structure Plastics are comprised of a multitude of long “macromolecules” called polymers.

These polymer molecules are comprised of long chains of repeating subunits. Interesting to note, the term polymer can be broken down into its Greek roots as follows: ‘poly-’ or ‘many’ and ‘-mer’ or ‘part’ – many parts [2]. In general, plastics can be divided into two categories: semi-crystalline and amorphous. Amorphous plastics are polymers that remain in a disordered state once cooled, whereas semi-crystalline plastics have the ability to form an arrangement of ordered molecules, or crystals [2]. The term semi-crystalline is used, because it is not possible for polymers to be completely crystalline.