Mixing with sustainable and recycled materials. How to get the best results

Mixing with sustainable and recycled materials. How to get the best results
In today's rapidly evolving landscape, the integration of sustainable and recycled materials into projects has become a critical consideration for organizations aiming to reduce their environmental footprint. To navigate this complex terrain effectively, it is essential to engage with experts like Smithers’ consultant Josh Guilliams, who can provide valuable insights and guidance on the best practices for incorporating these materials. In our discussion, Mr. Guilliams was asked to shed light on pivotal information organizations must consider which underscores the successful utilization of such materials in their future products and programs.

What materials have become popular options for improving the environmental lifecycle performance of compounds? 

There has been a lot of work over the last decade on various material options that could potentially be applied to new formulations for anything from tires to hoses to infill. There are no shortages of more sustainable options.

The real question is how they mix in compound formulations and how do those formulations affect the end-use application characteristics needed for product performance. A couple key materials that are receiving a lot of attention include:

1.    Recovered Carbon Black (rCB) Technology
The process of recycling carbon black from end-of-life tires not only diverts waste from landfills but also significantly lowers the carbon footprint associated with producing carbon black from fossil fuels. Incorporating rCB into rubber compounds and other materials allows manufacturers to lower the overall environmental impact of their products while maintaining performance characteristics.  This shift towards using rCB contributes to a more circular economy model and could help address sustainability challenges in the tire and rubber industries.

2.    Devulcanized polymer technology
Devulcanized polymer technology enables the reuse of vulcanized rubber materials. Instead of discarding rubber products at the end of their lifecycle, devulcanization allows for the restoration and reprocessing of rubber, reducing the demand for new raw materials and lowering the carbon footprint associated with rubber production. By incorporating devulcanized rubber into new compounds, manufacturers can reduce their environmental impact, promote resource efficiency, and mitigate some of the environmental burdens typically associated with rubber waste disposal.

3.    Silica Rice Husk
Silica from rice husks offers significant environmental benefits by utilizing a renewable agricultural byproduct to produce silica for various compounds. By extracting silica from rice husk, manufacturers can reduce their reliance on traditional silica production methods, which often involve energy-intensive processes and contribute to greenhouse gas emissions. This sustainable sourcing of silica not only reduces the environmental impact of silica production but also provides a value-added use for agricultural waste, promoting circular economy practices. 

4.    Raw Material Technology produced from renewable sources
Raw material technology produced from renewable sources helps us shift away from fossil fuel-derived feedstocks. By using bio-based feedstocks such as biomass, algae, or agricultural byproducts, manufacturers can significantly reduce their carbon footprint and dependence on finite resources.  A few examples include multiple sources for natural rubber (e.g. Russian dandelion, guayule), renewable carbon black from bio-based feedstocks, and crude tall oil (CTO) and crude sulphate turpentine (CST). As a valuable by-product of the Kraft pulp industry, CTO, CST, and its primary bio-refinery products are renewable feedstock bases for high-quality products and sustainability performance. CTO and CST are 100 percent biobased materials with a steady supply all year round, do not compete for land with food crops, are not genetically modified (non-GMO), and boast stable quality. 

These are just several examples of renewable sources that could provide feasible replacements for use in numerous applications.

Specific to recycled or recovered carbon black, what mixing factors must you consider optimizing your compound’s performance?

Whenever examining new materials for use in a compound, it is important to evaluate the material properties first.  The team must first define the specification range of the new material compared to existing solutions and determine the range of desired properties that could be expected.  

With rubber compounding, there is always a tradeoff with what formulation properties are affected by the new material. We tend to ask questions like, "Does the new material age in a manner consistent with the existing solutions? Should we examine heat, oxygen, ozone, UV durability?" 

Many new solutions have well-defined targets, but others do not. So, we tend to ask what grades we are looking to offset and if they are reinforcing grades. We also want to know the purity of the new solution.

Depending on the targeted application, the range of physical properties which may need to be tested cover a broad distribution, but the material’s intrinsic properties should always be understood first.

  • Loading level of carbon black being used
  • The level of reinforcement needed in the compound to achieve desired properties.
  • Drop temperature/energy consumption utilized in the formulation.
  • Application of the formulation

What factors do you need to consider to ensure your program meets the intended goals and can assist you with building your final product value proposition?

The key factors to consider when developing the program with our experts include.

  • End-use application
  • Material performance properties vs. current or desired benchmarks
  • Environmental factors

Ultimately, every program will be slightly different and needs to be tailored to the needs of these factors. In some cases, material property benchmarking and comparisons may not be enough to properly validate the concept for the end client. Final product testing and validation in the field or against industry standards in a laboratory environment will be required to support a true comparison.

In the case of new material usage in tires, having test tires manufactured and tested to current durability and performance standards may also be required. In the case of new ingredients for tread compounds, for example, rolling resistance testing and wet grip testing may be required. The more critical the product performance and safety requirements of the product, the more additional validation data sets will be needed for final approval. Smithers covers the full gamut of testing from material chemistry and mixing through product validation allowing for a myriad of options to complete your testing program.  

What would you like anyone reading this know about how Smithers can help?

Our mixing and physical properties testing team can provide mixing studies covering a variety of applications. With multiple technologies at our disposal and a full range of physical testing capabilities, we can cover a wide variety of investigations. Our technical consultants can also support programs where you may need additional final product testing or a little additional guidance and interpretation.

To learn more about small batch rubber mixing, get in touch with Josh Guilliams at jguilliams@smithers.com

Latest Resources

See all resources