Effect of Lignin Plasticization on Physico-Mechanical Properties of Lignin/Poly(Lactic Acid) Composites.

Kraft lignin (KL) or plasticized KL (PKL)/poly(lactic acid) (PLA) composites, containing different lignin contents and with and without the coupling agent, were prepared in this study using twin-screw extrusion at 180 °C. Furthermore, ε-caprolactone and polymeric diphenylmethane diisocyanate (pMDI) were used as a plasticizer of KL and a coupling agent to improve interfacial adhesion, respectively. It was found that lignin plasticization improved lignin dispersibility in the PLA matrix and increased the melt flow index due to decrease in melt viscosity. The tensile strength of KL or PKL/PLA composites was found to decrease as the content of KL and PKL increased in the absence of pMDI, and increased due to pMDI addition. The existence of KL and PKL in the composites decreased the thermal degradation rate against the temperature and increased char residue. Furthermore, the diffusion coefficient of water in the composites was also found to decrease due to KL or PKL addition.

Influence of Lignin and Polymeric Diphenylmethane Diisocyante Addition on the Properties of Poly(butylene succinate)/Wood Flour Composite.

Poly(butylene succinate) (PBS)/wood flour (WF) composites with different WF content were prepared by twin-screw extrusion at 160 °C. With increasing WF content, the tensile strength of the PBS/WF composite without polymeric diphenylmethane diisocyante (pMDI) decreased, while that of the composite with pMDI increased. The addition of kraft lignin (KL) deteriorated the tensile properties of the composites both with and without pMDI. The melt flow index (MFI) decreased with increasing WF content, but increased with increasing KL content. The addition of pMDI caused an increase in the melt viscosity of the PBS/WF and PBS/WF/KL composites, resulting in a decrease in the MFI. The composites had lower thermal stability than neat PBS. The exotherms of the PBS/WF (50/50) composite appeared at a higher temperature than that of the neat PBS, but the PBS/WF/KL (50/50/20) composites had similar exotherms as the neat PBS. The addition of KL caused a decrease in the crystallization rate of PBS.

Variation in Graft Bending Angle During Range of Motion in Single-Bundle Posterior Cruciate Ligament Reconstruction: A 3-Dimensional Computed Tomography Analysis of 2 Techniques.

PURPOSE: To compare variations in femoral graft bending angle during range of motion (ROM) of the knee between inside-out (IO) and retro-socket outside-in (OI) techniques in posterior cruciate ligament (PCL) reconstruction using in vivo 3-dimensional (3D) computed tomography analysis. METHODS: Ten patients underwent PCL reconstruction by the IO technique (5 patients) or the retro-socket OI technique (5 patients) for suspensory femoral fixation. After PCL reconstruction, 3D computed tomography was performed in 0° extension and 90° flexion to reconstruct 3D femur and tibia bone models using Mimics software. Positions of femur and tibia at 30°, 45°, and 60° flexion were reproduced by determining the kinematic factors of anteroposterior translation, mediolateral translation, and internal-external rotation angle of each patient based on previously measured kinematic data. Variation in graft bending angle according to the flexion range of the knee was calculated by the difference in graft angulation measured at each flexion angle. The results were compared between the 2 techniques. RESULTS: There was significant difference in variation of femoral graft bending angle between IO and retro-socket OI techniques from 0° to 90° flexion of the knee (P = .008). Significant difference was also noticed at 30° to 45° (P = .008), 45° to 60° (P = .008), and 60° to 90° (P = .016) ROM of the knee between the 2 groups. CONCLUSIONS: The retro-socket OI technique resulted in less variation in femoral graft bending angle compared with the IO technique during knee ROM. We recommend the retro-socket OI technique for femoral tunnel placement to reduce the graft motion at the intra-articular femoral tunnel aperture. CLINICAL RELEVANCE: The retro-socket OI technique produces significantly less variation in femoral graft bending angle when compared with the IO technique. Such reduction in variation of femoral graft bending angle might be related to lower stress at the femoral tunnel aperture.

MnO2-deposited lignin-based carbon nanofiber mats for application as electrodes in symmetric pseudocapacitors.

Low-cost, high-performance electrodes are highly attractive for practical supercapacitor applications. MnO2-deposited carbon nanofiber mats (MnO2-CNFMs) are prepared for use as binder-free supercapacitor electrodes. MnO2 is deposited on the mats in situ by hydrothermally decomposing aqueous KMnO4, leading to the formation of nanocrystals of MnO2. The MnO2-CNFM electrode produced with 38.0µmol KMnO4 (this electrode) shows a high specific capacitance of ~171.6F·g-1 at a scan rate of 5mV·s-1. Moreover, a symmetric supercapacitor with the electrode exhibits a specific capacitance of 67.0F·g-1, an energy density of 6.0Wh·kg-1 and a power density of 160W·kg-1 at a special current of 0.1A·g-1. Further, the symmetric supercapacitor displays excellent cycling stability, retains approximately 99% of the capacitance after 1000cycles. The simplicity and ease of preparation of the MnO2-CNFMs as well as their suitability for use in coin-type supercapacitor cells make them ideal for application in cost-effective and high-performance electrodes for supercapacitors.