Cross-linked polyethylene, better known as PEX, is one of the newer engineered materials. It was first introduced in North America in the mid-1980s for use in radiant heat. Today, it is found in cross-linked polyethylene plumbing and has a myriad of other uses. PEX is a preferred alternative to polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC) or copper tubing when hot water flow is required.
Cross-linking polyethylene lengthens the polymer chain and increases tensile strength. It can then be heated without movement, and the process improves abrasion resistance. Cross-linking different compounds to polyethylene produces different PEX characteristics. In general, three categories of additives produce different types of PEX. For example, PEX-a is low tension and has higher flexibility and is softer and tougher than irradiated PEX.
PEX’s ability to withstand the movement of hot liquid is its most distinguishing characteristic and the main reason the material has gained favor over the years. Other general PEX characteristics include:
Widely used in a variety of industries and applications, PEX pipe fittings are one of its most common applications. PEX is a popular choice in industries and applications, including:
Plastic injection molding with PEX can produce parts that exhibit long-lasting endurance in many environments. However, it is not the best choice if rigidity is a requirement. While still at the lower end of the cost scale, it is slightly more expensive than common PVC. Selecting the best material requires a thorough understanding of the material properties, performance, and cost.