Influence of lactic acid-grafted multi-walled carbon nanotube (LA-g-MWCNT) on the electrical and rheological properties of polycarbonate/poly(lactic acid)/ LA-g-MWCNT composites

Poly (lactic acid) blends: Processing, properties and applications

Poly (lactic acid) or polylactide (PLA) is a commercial biobased, biodegradable, biocompatible, compostable and non-toxic polymer that has competitive material and processing costs and desirable mechanical properties. Thereby, it can be considered favorably for biomedical applications and as the most promising substitute for petroleum-based polymers in a wide range of commodity and engineering applications. However, PLA has some significant shortcomings such as low melt strength, slow crystallization rate, poor processability, high brittleness, low toughness, and low service temperature, which limit its applications. To overcome these limitations, blending PLA with other polymers is an inexpensive approach that could also tailor the final properties of PLA-based products. During the last two decades, researchers investigated the synthesis, processing, properties, and development of various PLA-based blend systems including miscible blends of poly l-lactide (PLLA) and poly d-lactide (PDLA), which generate stereocomplex crystals, binary immiscible/miscible blends of PLA with other thermoplastics, multifunctional ternary blends using a third polymer or fillers such as nanoparticles, as well as PLA-based blend foam systems. This article reviews all these investigations and compares the syntheses/processing-morphology-properties interrelationships in PLA-based blends developed so far for various applications.

Highly N-doped microporous carbon nanospheres with high energy storage and conversion efficiency

Porous carbon spheres (CSs) have distinct advantages in energy storage and conversion applications. We report the preparation of highly monodisperse N-doped microporous CSs through the carbonization of polystyrene-based polymer spheres and subsequent activation. The N-doped microporous CSs have a remarkably high N-doping content, over 10%, and high BET surface area of 884.9 m² g⁻¹. We characterize the synergistic effects of the micropores and N doping on the energy storage performance of a supercapacitor electrode consisting of the CSs and on the performance in an electrocatalytic reaction of a CS counter electrode in a photovoltaic cell. The N-doped microporous CSs exhibit a maximum capacitance of 373 F g⁻¹ at a current density of 0.2 Ag⁻¹, a high capacitance retention up to 62% with a 10-fold increase in current density, and excellent stability over 10,000 charge/discharge cycles. A counter electrode consisting of N-doped microporous CSs was found to exhibit superior electrocatalytic behavior to an electrode consisting of conventional Pt nanoparticles. These CSs derived from polymer spheres synthesized by addition polymerization will be new platform materials with high electrochemical performance.