Phase morphology, rheological behavior and mechanical properties of supertough biobased poly(lactic acid) reactive ternary blends.

Poly(lactic acid) (PLA) is one of the most promising bio-based polyester with great potential to replace for the petroleum-based polymers, which can significantly reduce greenhouse gas emissions. However, the inherent brittleness of PLA seriously restricts its broad applications. Herein, PLA/poly(ε-caprolactone) (PCL)/ethylene methyl acrylate-glycidyl methacrylate (EMA-GMA) ternary blends with different phase structures were prepared through reactive blending. The reactions between the epoxy groups of EMA-GMA and the carboxyl and hydroxyl end groups of PLA and PCL and were evidenced from the Fourier transform infrared spectroscopy, dynamic mechanical analysis and rheological results. The atomic force microscopy (AFM) images clearly revealed the formation of stack structure of the PCL and EMA-GMA minor phases in PLA/PCL/EMA-GMA (80/15/5) blend, and core-shell particle structures in PLA/PCL/EMA-GMA (80/10/10) and (80/5/15) blends. In terms of elongation at break and impact toughness, PLA/PCL/EMA-GMA (80/5/15) blend presents the best properties among all the compositions. Moreover, it also behaved excellent stiffness-toughness balance. The toughening mechanism can be ascribed to the formation of core-shell structure and the existence of interfacial adhesion in the ternary blends. This work can provide guide for the preparation and design of PLA-based partially renewable supertough materials that can compete with conventional petro-derived plastics.

Markedly improved hydrophobicity of cellulose film via a simple one-step aminosilane-assisted ball milling.

Most cellulose products lack water resistance due to the existence of abundant hydroxyl groups. In this work, microfibrillated cellulose (MFC) was modified via 3-aminopropyltriethoxysilane (APTES)-assisted ball milling. Under the synergism between high-energy mechanical force field and APTES-modification, the fibrillation and hydrophobization of MFC were achieved simultaneously. Free-standing translucent cellulose films made of modified MFC were fabricated. The original crystal form of cellulose is maintained. The hydrophobicity of cellulose film markedly increases and the water contact angle goes up to 133.2 ± 3.4°, which might be ascribed to the combined effects of APTES-modification and rough film surface. In addition, the thermostability and mechanical properties of cellulose film are also improved via mechanochemical modification. This work provides a novel one-step fibrillation-hydrophobization method for cellulose.

A self-reinforcing and self-healing elastomer with high strength, unprecedented toughness and room-temperature reparability.

The development of intrinsic self-healing elastomers with simultaneous high mechanical strength, toughness and room-temperature reparability remains a formidable challenge. Herein, we report a mechano-responsive strategy, known as strain induced crystallization, to address the above issue, whereby synthesized elastomers with unprecedented high mechanical performances are bestowed with room-temperature self-healing materials, achieving tensile strength, toughness and fracture energy values of 29.0 MPa, 121.8 MJ m-3 and 104.1 kJ m-2, respectively.