Effects of potassium dimethyl 5-sulfoisophthalate as a nucleating agent on rCF/PBAT composites

As a primary alternative to conventional synthetic and petroleum-based plastics, PBAT suffers from slow crystallization rate and low crystallinity, necessitating crystallization modification to improve mechanical, thermal, and processing properties for broader application in structural materials. However, a single strategy cannot synergistically regulate both efficient nucleation and oriented crystallization. To address this limitation, this study introduced potassium dimethyl 5-sulfoisophthalate (NA301 L) as a nucleating agent alongside recycled carbon fiber (rCF) as reinforcement to modify PBAT crystallization and prepared NA301 L/rCF/PBAT composites. The effects of NA301 L loadings on the mechanical, crystallization and thermal properties of composites were investigated to identify the optimal content, aiming at high-value utilization of rCF and high-performance modification of PBAT-based composites while alleviating environmental and resource pressures from rCF waste. Results showed that NA301 L markedly improved the crystallization behavior, increasing crystallization temperature, crystallization rate and crystallinity. At 1.5 wt% NA301 L, flexural strength and flexural modulus improved by 8.7% and 15.2% compared with rCF _25% /PBAT _75% composites, impact strength reached 113.41 kJ/m ² , with favorable interfacial bonding observed by SEM. Thermal characterization further revealed that the crystallinity improved by 29.8%, half-crystallization time shortened by 11.7%, and Vicat softening temperature (VST) raised by 5.4°C, enhancing the high-temperature deformation resistance of composites, demonstrating the best nucleating effect at 1.5 wt% NA301 L.