Fabrication of recyclable nucleating agent and its effect on crystallization, gas barrier, thermal, and mechanical performance of Poly( -lactide)

Furan-based renewable elastomers as effective tougheners for PLA: Enhanced mechanical properties and water vapor barrier properties

There is a great need for versatile biomass additives sourced from renewable materials to enhance the performance of polylactic acid (PLA) composites. This study introduces a furan-based polyester elastomer called PNF-PBC that is designed to improve the mechanical and water vapor barrier characteristics of PLA. By incorporating PNF-PBC into PLA, the toughness of the PLA/PNF-PBC biocomposites was considerably enhanced through various intermolecular interactions. A 15 wt% PNF-PBC blend with PLA exhibited a 13.6-fold increase in elongation at break, while having a negligible impact on tensile strength. Furthermore, the water vapor barrier performance of PLA/PNF-PBC biocomposites was greatly boosted by a factor of 10 compared to pure PLA, making them highly suitable for food packaging materials. With its versatile properties, we anticipate that this bio-based PLA/PNF-PBC material will significantly expand the range of applications for PLA composites.

Effects of Different End Functional Groups Hyperbranched Polymers-Modified Carbon Nanotubes on the Crystallization and Mechanical Properties of Poly(l-lactic acid) (PLLA)

Poly-l-lactic acid (PLLA) is a biodegradable polymer with great mechanical properties and good transparency, but its low crystallization rate greatly limits its application. Hyperbranched polyesters (HBPs) modified carbon nanotubes (CNTs) are an ideal nucleating agent to prove the crystallization of PLLA. To compare different terminal group HBPs' effect on the modification of CNTs and the crystallization of PLLA, through the condensation reaction and amidation reaction, CNTs-H202 and CNTs-N102 were prepared, respectively. The modification was confirmed by Fourier-transform infrared (FTIR) spectroscopy, X-ray electron spectroscopy (XPS), and thermogravimetric analysis (TGA). Using transmission electron microscopy (TEM), we observed the changes on the surface of modified CNTs. PLLA/CNT composites were prepared, and differential scanning calorimetry (DSC) was used to investigate the crystallization behavior of the composites. The mechanical properties of PLLA/CNT composites were investigated as well. The results showed that the modified CNTs had a better promotion on PLLA crystallization and mechanical properties than the unmodified CNTs. CNTs-N102 had a slight advantage on the promotion on PLLA crystallization, which was caused by the lower grafting rate of HBP N102, and CNTs-H202 had a better promotion on the mechanical properties of PLLA, which was caused by the better compatibility with PLLA. In conclusion, hydroxy-terminated HBP is a better CNT modified material than amino-terminated HBP.

Effects of Amino Hyperbranched Polymer-Modified Carbon Nanotubes on the Crystallization Behavior of Poly (L-Lactic Acid) (PLLA)

Poly-L-lactic acid (PLLA) is an environmentally friendly and renewable polymer material with excellent prospects, but its low crystallization rate greatly limits its application. Through the amidation reaction between amino hyperbranched polymer (HBP N103) and carboxylated carbon nanotubes (CNTs), CNTs-N103 was obtained. The modification was confirmed by Fourier-transform infrared (FTIR) spectroscopy, X-ray electron spectroscopy (XPS) and thermogravimetric analysis (TGA). Using transmission electron microscopy (TEM), we observed the changes on the surface of modified CNTs. PLLA/CNT composites were prepared, and differential scanning calorimetry (DSC) was used to investigate the crystallization behavior of the composites. The results showed that the addition of CNTs could greatly improve the crystallization properties of PLLA; at the same concentration, the modified CNTs had better regulation ability in PLLA crystallization than the unmodified CNTs. Moreover, in the concentration range of 0.1–1%, with the increase in HBP concentration, the ability of CNTs-N103 to regulate the crystallization of PLLA increased as well. Wide-angle X-ray diffraction (WAXD) once again proved the improvement of the crystallization ability. The results of polarized optical microscopy (PLOM) showed that the number of nucleation points increased and the crystal became smaller.