The aim of this study was to gain a better understanding of the crystallization behavior of triethyl‐citrate‐plasticized poly(lactic acid) (PLA–TEC) in the presence of chitin nanocrystals (ChNCs). The isothermal crystallization behavior of PLA–TEC was studied by polarized optical microscopy, scanning electron microscopy, differential scanning calorimetry, and X‐ray diffraction (XRD). Interestingly, the addition of just 1 wt % ChNCs in PLA–TEC increased the crystallization rate in the temperature range of 135–125 °C. The microscopy studies confirmed the presence of at least three distinct types of spherulites: negative, neutral, and ring banded. The ChNCs also increased the degree of crystallinity up to 32%, even at a fast cooling rate of 25 °C min⁻¹. The XRD studies further revealed the nucleation effect induced by the addition of ChNCs and thus explained the faster crystallization rate. To conclude, the addition of a small amount (1 wt %) of ChNC to plasticized PLA significantly affected its nucleation, crystal size, and crystallization speed; therefore, the proposed route can be considered suitable for improving the crystallization behavior of PLA. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47936.

The orientation of polymer composites is one way to increase the mechanical properties of the material in a desired direction. In this study, the aim was to orient chitin nanocrystal (ChNC)-reinforced poly(lactic acid) (PLA) nanocomposites by combining two techniques: calendering and solid-state drawing. The effect of orientation on thermal properties, crystallinity, degree of orientation, mechanical properties and microstructure was studied. The orientation affected the thermal and structural behavior of the nanocomposites. The degree of crystallinity increased from 8% for the isotropic compression-molded films to 53% for the nanocomposites drawn with the highest draw ratio. The wide-angle X-ray scattering results confirmed an orientation factor of 0.9 for the solid-state drawn nanocomposites. The mechanical properties of the oriented nanocomposite films were significantly improved by the orientation, and the pre-orientation achieved by film calendering showed very positive effects on solid-state drawn nanocomposites: The highest mechanical properties were achieved for pre-oriented nanocomposites. The stiffness increased from 2.3 to 4 GPa, the strength from 37 to 170 MPa, the elongation at break from 3 to 75%, and the work of fracture from 1 to 96 MJ/m³. This study demonstrates that the pre-orientation has positive effect on the orientation of the nanocomposites structure and that it is an extremely efficient means to produce films with high strength and toughness.

The demand for high-performance polymers in 3D printing continues to grow due to their ability to produce intricate and complex structures. However, commercially available high-temperature 3D printing materials often exhibit limitations such as brittleness, warping, thermal sensitivity, and high costs, highlighting the need for advanced filament development. This study investigates the fabrication of polyetherimide (PEI) and polycarbonate (PC) blends via melt extrusion to enhance material properties for stable additive manufacturing. The addition of PC improved the processability of the blends, enabling successful extrusion at temperatures ranging from 290 to 310 °C. Differential scanning calorimetry (DSC) confirmed a shift in the softening temperature (T) of PEI, indicating effective blending. To further improve the properties of the PEI:PC blends, 1 wt% of a compatibilizer was incorporated, resulting in homogeneous microstructures as observed through scanning electron microscopy (SEM). The optimized PEI:PC (70:30) blend with compatibilizer (1 wt%) demonstrated a 49% higher storage modulus than neat PEI and a 40% greater storage modulus than ULTEM9085. Moreover, reduced melt viscosity facilitated consistent and stable printing, making these materials highly suitable for applications in aerospace and transportation, where performance and reliability are critical.