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May 2024 | VOL. 4 | ISSUE 2

POLYMERS 102:

PREVENTING POLYMER UV DEGRADATION

 

In the world of polymers (with the exception of fluoropolymers), UV and oxygen can be detrimental to a material's stability. Whether using polyvinyls like PVC or CPVC or polyolefins like PE or PP, both material types can be subject to UV and oxidative breakdown. Formulators take great care to put additives in most thermoplastics that help prevent UV degradation in pipes over time, so let's examine what is happening with the pipe materials and what is used in the industry to preserve them for longer periods of time.

First, it would be helpful to look at how a polymer breaks down in this reaction. Note that this section is a little "chemistry" heavy, but I will walk you through it (PE = polymer, H = hydrogen, O = oxygen, * = free radical):

PE-H —(UV, Heat)—> PE* + H*

Note: the * means that a reactive "free radical" has formed.

PE* + O2 —> PE-O-O*

WHY EXPERTISE MATTERS

IN FABRICATION

 

 

Significant industrial growth in the last decade has challenged industries and contracting firms to construct and deliver completed facilities as contracted quickly. The goal is to complete the build in record time and under budget while not compromising quality. Today, job sites are congested and cluttered with competing trades, and everyone strives to deliver their scope of work as committedly as possible. Offsite manufacturing (OSM) is becoming widely leveraged as the answer to meeting these challenges.

Technologies and tools like Building Information Modeling (BIM) and  Computer-Aided Design (CAD) have proven essential in the planning and layout of piping systems in prefabrication. These technologies allow for an earlier review of the design methodology, detection of potential clashes, and minimizing waste, to name a few. By addressing areas of concern early on with the designers, integrators, and fabricators, corrective action can be taken to reduce the risk of time delays, design flaws, and unnecessary materials and components being utilized.

AN OVERVIEW OF INFRARED (IR) WELDING
 
 
Infrared (IR) welding is a non-contact method that uses a heated plate to melt thermoplastic pipe, valves, and fittings before joining. The welded components are heated at a prescribed distance from the heater plate for a precise time to ensure optimal temperature is achieved, after which the components are brought together under pressure and allowed to create a homogeneous weld joint.

The advantages of IR welding over other methods, particularly for High-Purity applications, are numerous. Additionally, the automated nature of the AGRU SP-Series of welding tools provides additional benefits, ranging from consistency to increased traceability.

  1. Non-contact heating results in zero material contamination from the heating element to the pipe materials. This means there is less opportunity to introduce contaminants into the system.

  2. The precise heating recipe makes for very small internal weld beads in the piping system.

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