A bio-flame retardant, calcium magnesium phytate (CaMg-Ph), was synthesized via the reaction of calcium chloride and magnesium chloride with phytic acid from renewable source. Poly(lactic acid) (PLA) biocomposites were fabricated using CaMg-Ph as a bio-sourced phosphorous additive combined with acid-treated carbon nanotubes (CNT). The thermal, mechanical and flame retardant properties of PLA biocomposites were evaluated by thermogravimetric analysis (TGA), tensile and cone calorimeter tests. The addition of the combinations (19 wt% CaMg-Ph and 1 wt% CNT) into PLA resulted in a slight increase in tensile strength (52.8 MPa), compared to 20 wt% CaMg-Ph (50.4 MPa), indicating the reinforcement effect of the CNT. The addition of 10, 20, and 30 wt% CaMg-Ph led to significant reduction in PHRR by 22%, 33%, and 38% respectively with a similar trend in THR. PLA/CaMg-Ph19/CNT1 showed lower PHRR (35.0%) and higher char yield (18.4 wt%) compared to PLA/CaMg-Ph20, suggesting the preferable flame retardant properties.
Due to bacteria in urine and inadequate blood supply, urethral defect repair faces great clinical difficulties. Inspired by the natural structure of the urethra, in this study, we designed a multifunctional hydrogel urethral patch with a Janus structure. The inner layer was a double-network hydrogel of polyvinyl alcohol/carboxymethyl chitosan (PVA/CMCS) enhanced by natural phytic acid (PA) and Mg 2+ (Mg 2+ -PA/PVA/CMCS). The outer layer was composed of poly (L-lactic acid) (PLLA) nanofibers to form a hydrophobic barrier, coupling via a micelle layer to ensure interfacial bonding. The patch exhibited mechanical properties matching soft tissues, with maximum tensile strength and toughness of 1.69±0.13 MPa and 24.7±0.9 MJ/m 3 , respectively, under the strengthening effect of Mg 2+ -PA chelation. Therein, the 4 % Mg 2+ -PA/PVA/CMCS composite patch could maintain unilateral hydrophobicity for at least 14 days and demonstrated an antibacterial rate of 99.0 %±0.1 % against E. coli . In PBS, the patch could deliver Mg 2+ for at least 7 days and stabilize the surrounding pH environment for up to 28 days. In vitro cell experiments indicated that the 4 % Mg 2+ -PA/PVA/CMCS composite patch could promote the human umbilical vein endothelial cell (HUVEC) proliferation and migration, with the angiogenic protein expression enhanced more than 1.2 times compared with the Control group. In conclusion, the patch constructed in this study may provide a new approach to clinical urethral injury repair.
危险品化学品经营许可证（带存储）