**7. A comparison of recycled polymeric materials using LCA methodology**

The results of the life cycle assessment (LCA) calculations are presented in **Figure 7**. The process flow in the calculations is as follows: Fiber production, transportation, spinning, warp preparation, dyeing and sizing, weaving, finishing, quality control & packaging. It should also be noted that the main differentiator in the calculation of impact categories is fiber mix.

## **7.1 Global warming potential**

The highest Global Warming Potential was calculated for Article 02–80% cotton & 20% PET. The particularly high result for this article is primarly related to its fossil fuel source and high energy requirement of fiber production stage. Once the polyester is recycled as in Article 03, the global warming potential decreases to the lowest value since depletion of fossil fuels is eliminated. On the other hand, the impact value decreases by 13% when the biobased polymer, PLA is used (Article 04). The fiber production stage is still an important contributor to the global warming potential value when Article 04 is considered.

Although production of pulp and wood-based fibers is also energy needed to process Tencel® and Refibra® does not only rely on fossil fuels. Lenzing site in Austria uses around 80% renewable energy whereas the pulp plant in Paskov employs 100% renewable fuels. Dissolving wood pulp production in Lenzing's biorefineries is not only self-sufficient in terms of meeting its own energy needs, it actually produces surplus energy. This surplus energy (steam and electricity) is used on-site for purposes such as fiber production or export to the local grid, which in turn lowers Lenzing products carbon footprint [84, 89].

**Figure 7.**

*The results of comparative LCA for different polymeric materials in denim fabric.*
