Zhao, Jinchuan
[Author];
Wang, Guilong
[Author];
Chai, Jialong
[Author];
Chang, Eunse
[Author];
Wang, Sai
[Author];
Zhang, Aimin
[Author];
Park, Chul B.
[Author]
Ultra-Tough and Strong Pla Nanocomposites Reinforced by Uv-Crosslinked In-Situ Epdm Nanofibrils with Outstanding Foaming and Thermally-Insulating Performance
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Media type:
E-Book
Title:
Ultra-Tough and Strong Pla Nanocomposites Reinforced by Uv-Crosslinked In-Situ Epdm Nanofibrils with Outstanding Foaming and Thermally-Insulating Performance
Description:
Plastic wastes have been globally recognized as an urgent environmental problem, threatening all life forms, ecosystems, and economic societies worldwide. In this context, polylactic acid (PLA), as an alternative biodegradable material of petroleum-based plastics, has received widespread attention, due to its high biocompatibility and strength. However, the natural brittleness and slow crystallization kinetics of PLA seriously limit its applications. Herein, a novel route by integrating in-situ nanofibrillation and UV crosslinking process was developed to fabricate tough and strong PLA/ ethylene-propylene-diene terpolymer (EPDM) composites with multifunctional properties. Thanks to the UV crosslinking process, the fibrillar structure of the EPDM phase was retained with an average diameter of 94.3 nm and a length/diameter aspect ratio of 100-fold, which significantly promoted the crystallization and melt strength of PLA. More importantly, the UV crosslinked EPDM (UV-EPDM) nanofibrils pronouncedly improved the mechanical properties of the PLA composite, resulting in 620% increase in toughness without sacrificing strength and 440% increase in notched impact strength compared to pure PLA. The UV-EPDM nanofibrils also effectively enhanced the foaming ability during the mold-opening microcellular injection molding process, whose expansion ratio increased 470%, cell population density increased 5 orders of magnitude, and cell size decreased 93% comparing with PLA foams. Due to the super-high expansion ratio and micro/nanoscale structures on the cell walls, the thermal conductivity of the PLA/EPDM nanocomposite foam was reduced to as low as 26.33 mW/m∙K. Thereby, this industry-related process has greatly broadened the application of PLA as toughness/strength-balanced components, creating potential opportunities for fabrication of high-performance polymer composites