Vanillin-based flame retardant enables polylactic acid high-efficiency fireproof, anti-UV and oxygen barrier for food packaging.

Polylactic acid (PLA) is widely known for its biocompatibility, biodegradability, and high transparency. However, it still has varied limitations such as flammability, UV sensitivity, and poor oxygen barrier properties. To address these issues, a bio-based compound, hexasubstituted cyclotriphosphazene (HVP), was synthesized by using vanillin and hexachlorocyclotriphosphazene to enhance the overall performance of PLA. The resulting PLA/HVP composites demonstrated improved mechanical strength and UV resistance. Specifically, PLA/3HVP, with a 3 wt% HVP loading, achieved a UL-94 V-0 rating and a high limiting oxygen index of 26.5 %. Cone calorimeter tests revealed that PLA/3HVP possessed a significantly longer ignition time and a lower peak heat release rate compared to pure PLA. These burning testing results indicated the enhanced fire resistance. Additionally, the oxygen transmission rate of PLA/3HVP was reduced by 81.1 % compared to pure PLA. When used as food packaging, the weight loss of mangoes covered with PLA/3HVP film was 2.2 % after 7 days, compared to 2.5 % with pure PLA film, highlighting its potential for food preservation applications.

Flexible Actuators Based on Conductive Polymer Ionogels and Their Electromechanical Modeling.

High-performance flexible actuators, integral components of soft robotics, hold promise for advancing applications in safe human-robot interactions, healthcare, and various other fields. Notable among these actuators are flexible electrochemical systems, recognized for their merits in low-voltage manipulation, rapid response speed, and cost-effectiveness. However, the optimization of output strain, response speed, and stability presents a significant challenge in this domain. Despite the application of diverse electrochemically active materials to enhance actuation performance, a critical need persists for corresponding electrical-mechanical models to comprehensively grasp actuation mechanisms. In this study, we introduce a novel electrochemical actuator that utilizes conductive polymer ionogel as active electrodes. This ionogel exhibits exceptional properties, including high conductivity, flexibility, and electrochemical activity. Our electrochemical actuators exhibit noteworthy bending strain capabilities and rapid response rates, achieving frequencies up to 10 Hz at a modest voltage of 1 V. An analytical model integrating ion migration and dynamic processes has been established to elucidate actuator behavior. Simulation results highlight that electrodes characterized by low resistance and high capacitance are optimal for simultaneous enhancement of bending strain and blocking force. However, the augmentation of Young's modulus, while increasing blocking force, compromises bending strain. Furthermore, a larger aspect ratio proves beneficial for unidirectional stress output, leading to increased bending strain, while actuator blocking force diminishes with greater length. These findings underscore the intricate interplay between material properties and dimensions in optimizing the performance of flexible electrochemical actuators. This work provides important practical and theoretical guidance for the manufacture of high-performance flexible actuators and the search for new smart materials.

Comparison of arterial stiffness and ultrasound indices in patients with and without chronic obstructive pulmonary disease

SUMMARY OBJECTIVE: The purpose of this study was to compare arterial stiffness and ultrasound indices in patients with and without chronic obstructive pulmonary disease. METHODS: In our retrospective study, 83 chronic obstructive pulmonary disease patients were assigned to the chronic obstructive pulmonary disease group and 80 healthy controls were enrolled. Pearson's correlation analysis software was used to analyze the correlation between arterial stiffness (including brachial ankle pulse wave velocity and ankle-brachial blood pressure index) and ultrasound index (including resistance index, pulsatility index, and intima-media thickness) at the carotid artery in chronic obstructive pulmonary disease patients. RESULTS: The ultrasound resistance index and pulsatility index level of chronic obstructive pulmonary disease group were lower than those of control group (t=6.326, 8.321, p<0.001). Compared with the control group, the chronic obstructive pulmonary disease group had higher intima-media thickness, total plaque area, and number of plaques (t=4.574, 7.493, 5.093, p<0.001). The arterial stiffness and ankle-brachial blood pressure index level in the chronic obstructive pulmonary disease group were higher than those in the control group (t=6.392, 5.109, p<0.001). Moreover, arterial stiffness in patients with chronic obstructive pulmonary disease was negatively correlated with the ankle-brachial blood pressure index, resistance index, and pulsatility index levels (p<0.05), while it is positively correlated with intima-media thickness, total plaque area, and number of plaques (p<0.05). CONCLUSION: Our results indicated that patients with chronic obstructive pulmonary disease have stiffer arteries compared with healthy control subjects; the ultrasound index could be used as an auxiliary indicator for clinical prediction of arterial stiffness, which is helpful to improve the accuracy of prediction and thus better guide clinical interventions in high-risk groups of chronic obstructive pulmonary disease in time.