The development of high-performance biodegradable polylactic acid (PLA) materials integrating high strength, malleability and toughness is desired but an ongoing challenge. In this work, a novel full-biobased block copolymer was designed and synthesized by grafting L (+)-lactide (L-LA) and ε-caprolactone (ε-CL) onto lignin via ring-opening polymerization. The obtained lignin-PLA-PCL block copolymer was composed of rigid lignin and poly (LA-CL) rubber segment, could self-assemble into uniform nano-micelles with average diameters of 80-100 nm regulated by simply altering copolymer content. The incorporation of lignin-PLA-PCL copolymers into PLA matrix induced the formation of many cavities, promoted free volume between PLA matrix and copolymer to accelerate chain mobility, achieving excellent ductility and stretchability with maximum stretching deformation of 64.8 %. The resultant PLA composites with the copolymer content as low as 5 wt% displayed simultaneously improved strength (41.84 MPa) and toughness (8.1 MJ/m), 6.7 % and 1520 % increment than those of neat PLA, respectively. The reinforcing and toughening mechanisms were explored and verified that the combination of cavity growth and fibrillation, followed by extensive shear yielding of matrix, causing substantial plastic deformation. This study extended the design strategy and the foundation for simultaneous reinforcing and toughening PLA plastics using lignin-derived rubbery micelles.
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http://dx.doi.org/10.1016/j.ijbiomac.2024.134159 | DOI Listing |
ACS Cent Sci
December 2024
Department of Chemistry, Shanghai Stomatological Hospital & School of Stomatology, State Key Laboratory of Molecular Engineering of Polymers, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, P. R. China.
An efficient regiospecific co-assembly (RSCA) strategy is developed for general synthesis of mesoporous metal oxides with pore walls precisely decorated by highly dispersed noble metal nanocrystals with customized parameters (diameter and composition). It features the rational utilization of the specific interactions between hydrophilic molecular precursors, hydrophobic noble metal nanocrystals, and amphiphilic block copolymers, to achieve regiospecific co-assembly as confirmed by molecular dynamics simulations. Through this RSCA strategy, we achieved a controllable synthesis of a variety of functional mesoporous metal oxide composites (e.
View Article and Find Full Text PDFNanomaterials (Basel)
December 2024
School of Materials Science & Engineering, Nanyang Technological University, Singapore 639798, Singapore.
This study investigates the effects of homopolymer additives and kinetic traps on the self-assembly of poly(ethylene glycol)-b-poly(lactide) (PEG-PLA) block copolymer (BCP) nanostructures in aqueous environments. By using non-adsorbing PEG homopolymers to kinetically trap PEG-PLA nanostructures, we demonstrate that varying the concentration and molecular weight of the added PEG induces a reversible micelle-to-vesicle transition. This transition is primarily driven by changes in the molecular geometry of the PEG-PLA BCPs due to excluded volume screening effects.
View Article and Find Full Text PDFBiomacromolecules
December 2024
School of Chemistry, Xi'an Key Laboratory of Sustainable Polymer Materials, Xi'an Jiaotong University, Xi'an 710049, Shaanxi, China.
X-ray-induced photodynamic therapy (XPDT) can penetrate deeply into the tumor tissues to overcome the disadvantage of conventional PDT. However, the therapeutic efficacy of XPDT in cancer therapy is still restricted due to the insufficient reactive oxygen species (ROS) generation at a relatively low irradiation dosage. Herein, we present the tumor pH and ROS-responsive polyprodrug micelles to load the X-ray photosensitizer verteporfin (VP) as an ROS production enhancer.
View Article and Find Full Text PDFAdv Mater
December 2024
School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China.
Carbon-supported single-atom catalysts exhibit exceptional properties in acidic CO reduction. However, traditional carbon supports fall short in building high-site-utilization and CO-rich interfacial environments, and the structural evolution of single-atom metals and catalytic mechanisms under realistic conditions remain ambiguous. Herein, an interconnected mesoporous carbon nanofiber and carbon nanosheet network (IPCF@CS) is reported, derived from microphase-separated block copolymer, to improve catalytic efficiency of isolated Ni.
View Article and Find Full Text PDFSmall
December 2024
School of Energy and Environment, Southeast University, Nanjing, Jiangsu, 210096, China.
Submicron particulate matter (PM) can penetrate deeply into human tissue, posing a serious threat to human health. However, the electrostatic charge of commercial respirators is easily dissipated, making it difficult to maintain long-term filtration. Herein, a hierarchically porous filter based on nanofibers with accessible porosity and particulate-attractive surfaces, achieving significant filtration performance is developed through polarity-driven interactions.
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