how do you do cross linked polyethylene

Cross-linked polyethylene

is high-density polyethylene that is manufactured by adding a catalyst to the thermoplastic resin, which turns it into a thermoset. The catalyst causes covalent bonds that link the molecules together. Picture a chain-link fence where the metal links are actually bonded or welded together.

Full Answer

How do you identify cross-linked polyethylene?

The plastic identification symbols for cross-linked polyethylene are XPE, XLPE, PE-Xb, and PEX. If there is no identification symbol, the best way to determine if the polyethylene is cross-linked or thermoplastic, is to try to melt it.

Can cross-linked polyethylene be welded?

Cross-Linked Polyethylene is not able to be welded. Cross-linked polyethylene does not have USDA or FDA compliance for storage of processing edibles. XLPE is the abbreviation for Cross-Linked Polyethylene. It is not recyclable like other polyethylene. A gel test is done to determine amount of cross-linking.

How do you make cross-linked bonds in polyethylene?

The process is accelerated with heat and moisture. The cross-linked bonds are formed through silanol condensation between two grafted vinyltrimethoxysilane (VTMS) units, connecting the polyethylene chains with C-C-Si-O-Si-C-C bridges.

Can you melt cross linked polyethylene?

Thermoplastic polyethylene will melt easily, but cross-linked polyethylene will not melt; t may turn brown or become soft and flexible, but it will not melt, as can be seen here. Now that we have determined we have cross-linked polyethylene, we can begin the repair process.

How is XLPE made?

Both linear polyethylene and XLPE tanks are made with heated resins to create a cured plastic. However, the differences in their production create very different polyethylenes with very different structural strength. Cross-linking is simply the formation of bonds between the polymer chains.

How does cross-linking occur in polymers?

Formation. Cross-links can be formed by chemical reactions that are initiated by heat, pressure, change in pH, or irradiation. For example, mixing of an unpolymerized or partially polymerized resin with specific chemicals called crosslinking reagents results in a chemical reaction that forms cross-links.

What is cross-linked polyethylene insulation?

XLPE or Cross-linked polyethylene is a thermoset insulation material. Crosslinking polymers is a process which changes the molecular structure of the polymer chains so that they are more tightly bound together and this crosslinking is done either by chemical means or physical means.

What is cross-linked polyethylene tubing?

Cross-linked Polyethylene (PEX) is a plastic material made from medium- or high-density polyethylene that is modified to have improved properties such as enhanced heat resistance and long term strength and stability that make it an excellent choice for use in service lines, hot- and cold-potable water distribution ...

What is cross linking process?

Crosslinking is the process of chemically joining two or more molecules by a covalent bond. Crosslinking reagents (or crosslinkers) are molecules that contain two or more reactive ends capable of chemically attaching to specific functional groups (primary amines, sulfhydryls, etc.) on proteins or other molecules.

What is a crosslinking agent?

KROS-lin-king AY-jent) A substance that binds DNA nucleotides together and blocks DNA synthesis. In cancer treatment, DNA cross-linking agents may kill cancer cells by damaging their DNA and stopping them from dividing.

Why XLPE is used?

XLPE is an acronym for cross linked polyethylene. XLPE is a thermosetting polymer meaning that the material (polyethylene (PE)) is cured under heat and in that process forms bonds in all directions forming a three dimensional matrix. Within this XLPE matrix there is space between the individual molecules.

What type of wire is XLPE?

stranded copper conductor wireXLPE wire is a single-stranded copper conductor wire that is insulated with hydronic tubing made of cross-linked polyethylene plastic (XLPE). The XLPE insulation has a three-dimensional bond within the plastic. The insulation is a thermoset, zero halogen insulation that provides flame retardant properties.

When should I use XLPE?

In short, XLPE cable should be used in industries that expose wire and cable to:Extreme temperature conditions (high and low)High voltage electrical applications.Abrasion and stress.Water and other liquids.Chemicals and other hazardous materials.

Is PEX a cross-linked polyethylene?

PEX pipes, also known as cross-linked polyethylene pipes, rely on plastics structurally modified for impact/tensile strengths, decreased shrinkage, high temperature/pressure performance, and resistance against creep, chemicals, and cracks.

How much does cross-linked polyethylene cost?

($1.42 /ft.)

Can XLPE be recycled?

XLPE used in cable applications is one of the cleanest materials to recycle and can be blended with various types of recyclates and virgin materials, including Polyethylene (PE) and Polypropylene (PP).

What are cross-linked polymers give two examples?

Examples of cross-linked polymers include: Polyester fiberglass, polyurethanes used as coatings, adhesives, vulcanized rubber, epoxy resins and many more.

Is nylon a cross-linked polymer?

Nylon and polyvinyl chloride are linear chain polymers (thermoplastics) while melamine and bakelite are cross-linked polymers (thermosetting plastics).

Is PVC a cross-linked polymer?

The polymer polyvinyl chloride is formed by the polymerization of polyvinyl chloride and it has a linear structure, so polyvinyl chloride is a linear polymer, not cross linked. The repeating unit or monomer of PVC is vinyl chloride.

How do you remove hydrogen from polyethylene?

In each method, a hydrogen atom is removed from the polyethylene chain (top center), either by radiation (hν) or by peroxides (R-O-O-R), forming a radical. Then, two radical chains can crosslink, either directly (bottom left) or indirectly via silane compounds (bottom right).

What is the required degree of cross-linking?

The required degree of cross-linking, according to ASTM Standard F876, is between 65% and 89%. A higher degree of cross-linking could result in brittleness and stress cracking of the material, while a lower degree of cross-linking could result in product with poorer physical properties.

Why are PEX pipes labeled?

All PEX pipe is manufactured with its design specifications listed directly on the pipe. These specifications are listed to explain the pipe's many standards as well as giving specific detailing about the manufacturer. The reason that all these specifications are given, are so that the installer is aware if the product is meeting standards for the necessary local codes. The labeling ensures the user that the tubing is up to all the standards listed.

What is XLPE insulation?

It is the most common polymeric insulation material. The acronym XLPE is commonly used to denote cross-linked polyethylene insulation. XLPE automotive duct. Automotive ducts and housings: PEX also referred to as XLPE is widely used in the aftermarket automotive industry for cold air intake systems and filter housings.

What is PEX pipe made of?

Almost all PEX used for pipe and tubing is made from high-density polyethylene (HDPE). PEX contains cross-linked bonds in the polymer structure, changing the thermoplastic to a thermoset. Cross-linking is accomplished during or after the extrusion of the tubing.

What is PEX used for?

It is used predominantly in building services pipework systems, hydronic radiant heating and cooling systems, domestic water piping, and insulation for high tension (high voltage) electrical cables. It is also used for natural gas and offshore oil applications, chemical transportation, and transportation of sewage and slurries. PEX is an alternative to polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC) or copper tubing for use as residential water pipes.

What is XLPE cable?

Almost all cross-linkable polyethylene compounds (XLPE) for wire and cable applications are based on LDPE . XLPE-insulated cables have a rated maximum conductor temperature of 90 °C and an emergency rating up to 140 °C, depending on the standard used. They have a conductor short-circuit rating of 250 °C. XLPE has excellent dielectric properties, making it useful for medium voltage—1 to 69 kV AC, and high-voltage cables —up to 380 kV AC-voltage, and several hundred kV DC.

What is crosslinked polyethylene foam?

Cross-linked polyethylene foam is exceptionally fine celled and suitable for projects that require thicker foam. It boasts a smooth and pleasant feel combined with outstanding chemical and physical properties, which makes it the preferred solution for several applications where thicker sections of closed cell foam are required.

What is XLPE foam?

Cross-linked polyethylene foam (XLPE) is a highly-versatile, flexible, and useful closed-cell foam characterized by a resistance to water and a compact feel.

Does Frank Lowe make polyethylene foam?

Frank Lowe offers branded and non-branded cross linked polyethylene foam in bun, roll, plank, and sheet forms across a range of different densities. We utilize state-of-the-art equipment and processes to create precise die cuts based on your specific requirements.

Can Frank Lowe help with CAD?

In the event you don’t have specifications, the team at Frank Lowe can still help! We can use our custom CAD generated design program and laser die cutting or water jet die cutting to create your initial prototype.

Can XLPE foam be laminated?

Even if we don’t have the exact brand of XLPE foam you need, simply let us know, and we’ll provide a solution. All of our foams can be die cut, embossed, laminated, and enhanced with a pressure-sensitive adhesive.

What is crosslinked polyethylene?

Cross-linked polyethylene is a thermoset plastic, which means it is not meltable. The plastic identification symbols for cross-linked polyethylene are XPE, XLPE, PE-Xb, and PEX. If there is no identification symbol, the best way to determine if the polyethylene is cross-linked or thermoplastic is to try to melt it.

How to fill a hole in plastic?

First, clean the plastic with EcoPrep plastic cleaner. Next, grind away the plastic around the punctured area to create a gradual bevel. The depth of the slope needs to be around 80% of the thickness of the base material, and the gap of the hole should be around 1/16 of an inch to allow melted plastic into the void. The beveled area and the gap will be the surface the filler rod will bond to. Hand sand the area with coarse sandpaper to roughen the surface or use a 50 grit Roloc disc on low speed. This will allow the filler rod to stick to the plastic by giving the plastic some tooth. Now that the surface is prepped, it is time to apply the filler rod.

What type of welding rod is used for a hot melt adhesive?

The thermoplastic polyethylene weld ing rod will be used as a hot melt adhesive. This process is similar to how we apply FiberFlex welding rod.

How to repair a hole in a plastic rod?

Melt the surface of the rod with the airless plastic welder, flip it over and stick it to the plastic. Force it down into the puncture mark. Do this a few times to cause the melted plastic on the inside to mushroom out. This will allow the filler rod to form a plug on the inside of the hole. After creating the plug, continue applying plastic to the beveled area by melting the filler rod, sticking it to the plastic, and smoothing it into the sanding scratches. Remember, do not try to melt the base material. Let the welder do the work, and make sure the rod is completely melted through. Apply just enough pressure to force the melted rod into the sanding scratches. When the entire beveled area is filled, gently smooth the area with your welder, and your repair is complete. Wait until the repair is completely cool before pressure testing it. If desired, you can sand the repair smooth, but this is not necessary.

How to make a bevel in plastic?

First, clean the plastic with EcoPrep plastic cleaner. Although not shown in previous segments, sometimes it’s helpful to draw a circle around the hole as a guide for making the bevel. Use a die grinder to make a gradual bevel around the hole, using the circle you drew as a guide. Use 50 grit sandpaper on a Roloc disc to roughen up the plastic you just beveled.

How to repair a crack in plastic?

If desired, you can sand the repair smooth, but this is not necessary. First, clean the plastic with EcoPrep plastic cleaner. Next, v-groove the crack with a die grinder, and then bevel the plastic around the crack. Use coarse sand paper or a 50 grit Roloc disc to roughen up the plastic.

What is the phone number for Polyvance?

If you have any questions, please don't hesitate to call technical support at 800-633-3047.

High-Quality Cross-Linked Polyethylene Foam Products

At Atlas Foam Products, we design and fabricate cross-linked polyethylene foam packaging, products, and components tailored to your custom specifications and exact application requirements. We utilize L200 and L300 cross-linked foam, also known as Youngboard or Minicel® foam.

Our Capabilities and Services

With over 50 years of experience, Atlas Foam Products is one of the top custom cross-linked polyethylene foam packaging providers in California. Backed by our years of repeat customers and superior customer satisfaction, we offer cost-effective packaging solutions and custom-fabricated products.

Have Questions?

Give us a call at 888-514-5040 or fill out the form to send a message to one of our Foam Experts. We proudly provide services to local areas including Los Angeles, San Fernando Valley, Santa Clarita Valley, Simi Valley, Ventura, Oxnard, Orange County, Riverside, San Bernardino, and the Contiguous U.S.

How is PEX pipe connected?

PEX pipe is typically connected using either a copper crimp ring or expansion fittings with outer expansion rings . In the crimping method, a copper crimp ring is put over the pipe near the end, a copper fitting is inserted into the pipe end, and a crimping tool is used to crimp the ring over the pipe and fitting. In the expansion fitting method, an expansion tool is used to open the diameter of the pipe, into which an expansion fitting is inserted.

How is PEX formed?

PEX is a polymeric material formed by the chemical joining of individual polyethylene molecules in a process called cross-linking. Cross-linking alters the performance of the original polyethylene polymer improving several key properties. The primary reason for cross-linking polyethylene (PE) is to increase the material's elevated temperature performance under load. In addition, cross-linking substantially improves the pipe's environmental stress crack resistance (ESCR), resistance to slow crack growth, chemical resistance, toughness and abrasion resistance.

How much elongation is required for a 100ft PEX pipe?

Elongation (linear expansion): Typical elongation is anywhere from 1" to 2.5" for every 100ft of PEX pipe at a 10°F temperature rise. Since PEX expands and contracts with temperature changes, it should be secured so as to provide sufficient space for expansion to occur.

When was Pex used?

Pex (Cross-Linked Polyethylene): PEX was first used for hot-water radiant heating in the early 1970's, and today is a reliable solution around the world for hot- and cold water plumbing, radiant heating and cooling, outdoor snow and ice melting, residential fire protection, hydronic (hot-water) building services piping, and other demanding applications such as natural gas piping (outside of North America).

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