Doctor Tim Hiller, from the German Institute of Textile and Fiber Research, presented the PHB2Pro project. This initiative focuses on processing PHA to form nonwoven fibers. The main constraints of this technology are the slow crystallization rate and low thermal stability of PHA. To address these challenges, different types of PHA were tested. Following initial characterization using TGA, SEC, rheology, and DSC, the polymers were processed via meltblowing, and the resulting nonwoven materials were analyzed—examining area weight, thickness, fiber diameter distribution, tensile strength, and degradation.

It was observed that P3HB polymers with lower molecular mass and narrow molecular mass distribution allowed for stable processing, but produced unstable fabrics. Conversely, polymers with higher molecular mass and a narrow distribution led to unstable processing. However, when using polymers with high molecular mass and a much broader molecular weight distribution, both processing and final product stability improved. This broader distribution enabled a wider processing window at lower temperatures (175–185 °C). Although lower temperatures reduce energy consumption, the resulting fibers were thicker than PLA or PP fibers processed at the same temperature. Consequently, the material's air permeability was significantly higher than that of PLA and PP, leading to faster degradation. Even compared to other compostable fibers, such as commercial cellulose or hemp, PHA showed much higher air permeability. To improve these properties, the addition of copolymers and plasticizers was tested. PHBH combined with ATBC produced the most promising results—maintaining low fiber diameter while improving tenacity and elongation.

Marta Teixeira, from the Technological Centre for the Textile and Clothing Industries of Portugal, introduced the Waste2BioComp project. One of the project’s goals is to produce PHA-based fibers and coatings for textile applications. To this end, three different PHA grades (amorphous P3HB and commercial PHBHHx), as well as blends of these, were processed using three different techniques. When wet spinning was selected, rounded fibers with uniform diameter but non-uniform surfaces were produced. While tenacity values were comparable, elongation rates varied considerably. DSC and TGA analyses showed that PHBHHx had the lowest melting temperature of the tested samples, while crystallinity, degradation temperature, and mass loss rate remained consistent. Overall, these fibers were deemed unsuitable for textile production due to their instability.

As a result, dispersion techniques were optimized, and spray and knife-coating methods were tested. These approaches produced more stable fibers with improved hydrophobic properties—especially when combined with commercial thickeners.