Enhancing the Ductility and Properties of Non-Vulcanized Polylactic Acid-Based Thermoplastic Natural Rubber Using Acetyl Tributyl Citrate

This study examines the effects of mastication time and the addition of a plasticizer (acetyl tributyl citrate (ATBC)) on the properties of non-vulcanized polylactic acid/natural rubber (PLA/NR) blends using a factorial design, along with the impact of changing the weight ratio of the blends. The results reveal the formation of plasticized PLA (P-PLA)-based thermoplastics with enhanced ductility. ATBC functions as both a PLA plasticizer and a compatibilizer in the binary PLA/NR system. However, improving compatibility requires the exclusive use of masticated NR with an appropriate mastication time (60 min) before blending. Optimal properties are achieved at a P-PLA/NR weight ratio of 90/10, maximizing the impact strength (~35.40 J/m) and toughness (~7.21 × 10⁶ MJ/m³). However, higher NR contents lead to reduced mechanical performance due to poor interfacial bonding. Thermal analysis reveals superior miscibility and dispersion in blends with a lower NR content (10 wt%), while the addition of plasticizers and NR leads to a decrease in the glass transition temperature (T_g) of the blends. The results suggest potential applications for developing biodegradable products with enhanced flexibility and improved low-temperature performance. The incorporation of ATBC can enhance material properties without relying on conventional synthetic compatibilizers.