Arkema organic peroxides in crosslinking


polymer crosslinking

As a trusted distributor of raw materials and chemicals, we’re proud to offer Arkema’s extensive range of globally renowned organic peroxides

Crosslinking is a fundamental process in the production of robust, durable polymers, and Arkema’s cutting-edge solutions are at the forefront of this technology. From automotive and construction to electronics and consumer goods, these peroxides are used across many industries and play an integral role in the development of various high-performance products.

RBH supports clients in optimising their manufacturing processes and enhancing their material properties, so in this blog, we’ll explore the advantages of crosslinking and how Arkema’s products can transform your polymer processing.

What is crosslinking in polymers?

Crosslinking is the process of creating a bond between two or more structures to link them together at various points. In polymers, this is the process that we use to ‘fuse’ several polymer molecules together by strong bonds (covalent bonds) to create a stronger, more rigid structure.

When we look at the structure of polymers, they are long chains of molecules which when they aren’t crosslinked, can move around and slide past each other. Naturally, this can make materials flexible and weak.

However, when crosslinks are formed between polymer chains, this creates a network structure that makes the material stronger and more durable. These crosslinks significantly improve the strength, stability and resistance of the polymer which is essential in the creation of high-performance materials.

Crosslinking is an irreversible process caused by chemical or physical reactions, and to achieve it we use crosslinking agents such as organic peroxides.

polymerisation process in crosslinking polymers

Understanding organic peroxides

Organic peroxides (PO) are carbon-based chemicals that contain a group of atoms known as a peroxide functional group (R-O-O-R’). This group is made up of two oxygen atoms (O-O) bonded together, with R and R’ being alkyl, aryl, or other organic substituents.

A key characteristic of organic peroxides is that they are unstable and known for their high reactivity. They can easily break down at a certain temperature to produce free radicals (highly reactive molecules) which makes them highly useful when looking to initiate chemical reactions.

Their role in crosslinking and how it works

When added to polymers, organic peroxides play a crucial role in facilitating the crosslinking of polymer chains and essentially act as a way to initiate the chemical reaction required.

Here’s a simple step-by-step process that breaks down how it happens:

  1. Decomposition and radical formation: Organic peroxides contain a weak oxygen bond that breaks down easily under heat or light. Upon decomposition, they generate free radicals.
  2. Initiation of crosslinking: These free radicals can abstract hydrogen atoms from polymer chains or react with double bonds in unsaturated polymers. This forms new radical sites on the polymer chains.
  3. Propagation: These newly formed radical sites can react with each other or with other polymer chains, leading to the formation of covalent bonds between chains. As this process continues, the result is a three-dimensional network of interconnected polymer chains.

An overview of Arkema organic peroxides

Arkema is a global leading producer of organic peroxides and is continuously evolving its portfolio with extensive research and development to create innovative chemicals.

As a trusted supplier of Arkema’s products in the UK, the RBH Group can supply their Luperox® brand of organic peroxides for the crosslinking of polyolefins and elastomers.

plastic polymer particles

Luperox® organic peroxides

Luperox® is Arkema’s flagship brand of organic peroxide. Renowned for their efficacy and versatility in initiating polymer crosslinking and polymerisation reactions, their extensive portfolio is designed to enhance the physical properties of rubber, polymer and plastic product formulations.

With various formulas and types including pastes, flakes, powders, and granules, they are suitable for a broad range of industrial applications. More information can be found here.

Luperox® Scorch Protection Grades

Arkema also offers this specialised line of peroxides, a unique innovation that provides greater control over the crosslinking process in polymer manufacturing.

Luperox SP® effectively collects free radicals during processing and gives them up during curing, meaning there is no need for additional antioxidants or peroxides to achieve the correct state of cure. This technology allows for processing to be done at higher temperatures with fewer steps, all without compromising on quality.

These grades are particularly useful in applications where preventing premature crosslinking (scorching) is critical for maintaining product quality and processing efficiency.

Luperox® Air

We’re proud to offer the latest technology developed by Arkema, Luperox® Air. This is a series of specialised organic peroxides designed for air-cured systems. It allows the curing of peroxide articles in the presence of oxygen without any of the surface degradation drawbacks.

These peroxides offer a unique solution for applications that require curing at ambient temperatures, such as automotive extrusion profiles.

To find out more about Arkema’s range of organic peroxides, please get in touch with us to speak to one of our specialist Market Managers.

Benefits of crosslinking with organic peroxides

Organic peroxides are used in many industries to manufacture, modify and crosslink polymers.

They offer many advantages to the polymer industry, making them a popular choice for various reasons, such as:

  • Versatility: Organic peroxides can be used with a wide range of polymers under different processing conditions, and the vast selection of peroxide stabilities available means there is a product to suit virtually every application.
  • Efficiency: The process of crosslinking with organic peroxides is cost-effective and efficient, as they can initiate the process at relatively low concentrations.
  • Controlled reactivity: For polymer formulators, having precise control over the process is key. Organic peroxides provide this level of control as they have predictable and consistent behaviours when they decompose.
  • Enhanced material properties: The end product is a crosslinked polymer that exhibits superior mechanical strength, chemical resistance and thermal stability.
  • Increased lifespan: Crosslinking helps polymers maintain their properties over time, reducing degradation and extending their lifespan which is particularly important for products exposed to environmental conditions such as UV radiation and oxidation.

Crosslinking agents are one of the most important additives used in polymers, but organic peroxides aren’t the only products used. RBH can also provide a range of other crosslinkers including phenolic resins, sulphur accelerators and zinc oxide. 

Each product has its own advantages and is suitable for different applications. For technical guidance and support on the best crosslinker for your formulation, get in touch with us.

creating strong polymers by crosslinking with organic peroxides

Applications of organic peroxides in crosslinking

Arkema’s organic peroxides are used by manufacturers across the globe to significantly enhance the properties of their products used in various industrial processes. 

Some key applications include:

Rubber

An essential additive in the rubber vulcanisation process, organic peroxides help to create rubber with superior strength, elasticity, and durability. 

Peroxide-cured rubber often has better heat resistance and stability compared to sulfur-cured rubber, making it ideal in the manufacturing of automotive components such as tyres and seals.

Plastics

When strong plastics are required, crosslinked polyethylene (PEX) is the most suitable material, developed by adding organic peroxides to enhance the material’s resistance to high temperatures, chemicals and mechanical stress.

These properties make crosslinked plastics suitable for the most demanding applications and are commonly used in plumbing, heating, and cable insulation.

Adhesives & sealants

Reliable adhesion is paramount in many critical applications in construction, automotive and aerospace. To guarantee superior bond strength and performance, organic peroxides are used to facilitate the crosslinking of adhesive and sealant formulations.

Beyond strong adhesion, these types of products are also more resistant to solvents and environmental factors, extending their longevity.

Coatings

Both protective and decorative coatings can benefit from peroxide crosslinking, as the process delivers an end product that has enhanced durability, hardness, and chemical resistance.

The crosslinked network in coatings also provides a tough barrier against physical and chemical wear, ensuring long-lasting protection and an increased service life.

Need help with optimising your polymer formulations?

RBH specialises in helping manufacturers overcome complex challenges in the production of complex formulations. We can source and supply a range of materials and chemicals that can transform your products, and offer expert technical support to a diverse range of industries.

We can offer an extensive portfolio of products from global leading producers that can enhance your polymer formulations. To find out more about how we can help please get in touch with us, we’d love to hear from you.

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