Vitrimeric Polylactide by Two-step Alcoholysis and Transesterification during Reactive Processing for Enhanced Melt Strength.

Because of its rather low melt strength, polylactide (PLA) has yet to fulfill its promise as advanced biobased and biodegradable foams to replace fossil-based polymer foams. In this work, PLA vitrimers were prepared by two-step reactive processing from commercial PLA thermoplastics, glycerol, and diphenylmethane diisocyanate (MDI) using Zn(II)-catalyzed addition and transesterification chemistry. The transesterification reaction of PLA and glycerol occurs with zinc acetate as the catalyst, and chain scission will take place due to the alcoholysis of the PLA chains by the free hydroxyl groups from the glycerol.

Phase change mediated mechanically transformative dynamic gel for intelligent control of versatile devices.

Traditional devices, including conventional rigid electronics and machines, as well as emerging wearable electronics and soft robotics, almost all have a single mechanical state for particular service purposes. Nonetheless, dynamic materials with interchangeable mechanical states, which enable more diverse and versatile applications, are urgently necessary for intelligent and adaptive application cases in the future electronic and robot fields. Here, we report a gel-like material composed of a crosslinking polymer network impregnated with a phase changing molten liquid, which undergoes an exceptional stiffness transition in response to a thermal stimulus.

Orthogonal test design for optimization of the extraction of flavonid from the Fructus Gardeniae.

Objective: It is imperative to provide some consistent experimental results for the extraction of flavonid from Fructus Gardeniae.

Methods: The key extraction parameters that influenced the yield of flavonid from Fructus Gardeniae were optimized by employing an orthogonal experiment [L(9)(3)(4)], including the ratio of buffer solution (Na(2)B(4)O(7)·10H(2)O) to raw material, concentration of Fructus Gardeniae in extracting solution, extraction time and pH of buffer solution. An UV/Vis detector was used to perform the qualitative and quantitative analyses of the extracted flavonid with the using of the standard sample.

Investigation on reliability and scalability of an FBG-based hierarchical AOFSN.

The reliability and scalability of large-scale based optical fiber sensor networks (AOFSN) are considered in this paper. The AOFSN network consists of three-level hierarchical sensor network architectures. The first two levels consist of active interrogation and remote nodes (RNs) and the third level, called the sensor subnet (SSN), consists of passive Fiber Bragg Gratings (FBGs) and a few switches.