Solvent-Free One-Shot Synthesis of Thermoplastic Polyurethane Based on Bio-Poly(1,3-propylene succinate) Glycol with Temperature-Sensitive Shape Memory Behavior.

In this work, a new family of fully biobased thermoplastic polyurethanes (TPUs) with thermo-induced shape memory is developed. First, a series of TPUs were successfully synthesized by the one-shot solvent-free bulk polymerization of bio-poly(1,3-propylene succinate) glycol (PPS) with various molecular weights (M n = 1000, 2000, 3000, and 4000), 1,4-butanediol (BDO), and 4,4'-methylene diphenyl diisocyanate (MDI). These polyurethanes (PUs) are denoted as PPS-x-TPUs (x = 1000, 2000, 3000, and 4000), where x represents the M n of PPS in the polymers. To determine the effect of the molecular weight of the soft segment of PU, all PPS-TPUs were formed with the same hard segment content (32.5 wt %). The soft segment with high molecular weight in PPS-4000-TPU caused a high degree of soft segment entanglement and formed many secondary bonds. PPS-4000-TPU exhibited better mechanical (tensile strength: 64.13 MPa and hardness: 90A) and thermomechanical properties (maximum loading: 2.95 MPa and maximum strain: 144%) than PPS-1000-TPU. At an appropriate shape memory programming temperature, all synthesized PPS-x-TPUs exhibited excellent shape memory behaviors with a fixed shape rate of >99% and a shape recovery rate of >86% in the first round and 95% in the following rounds. Therefore, these bio-TPUs with shape memory have potential for use in smart fabrics.

New reductant-free synthesis of gold nanoparticles-doped chitosan-based semi-IPN nanogel: A robust nanoreactor for exclusively sensitive 5-fluorouracil sensor.

We report a novel class of chitosan (CS)-based hybrid semi-interpenetrating nanogel catalyst by the reductant-free green synthesis of gold nanoparticles (Au NPs) within the CS-poly(methacrylic acid) (Au@CS-PMAA) polymer network. The covalently cross-linked Au@CS-PMAA nanogel with CS chains semi-interpenetrating (semi-IPN) in the PMAA cross-linked network show superior colloidal stability and improved catalytic activity. The synthesized Au@CS-PMAA semi-IPN nanogel was applied as a superior modifier to create a new and sorely selective electrochemical sensing platform for the determination of antileukemic drug 5-fluorouracil (5-FU). The existence of -OH and -COOH groups in the CS and PMAA offers numerous binding sites for 5-FU. This assures the incorporation of Au NPs which affords a larger surface area and ameliorate electrical conductivity. Besides, the synergic effect amid both compounds improves the detection of 5-FU. Under optimal conditions, the constructed sensor offered a good performance in determination of 5-FU with a wide linear range from 0.1-497 µM and low detection limits of 0.03 µM, respectively. Further, this study proved that the fabricated sensor could be useful for analysis of 5-FU in actual human blood serum samples.