Jiahao He,Zhijiang Liu,Wenlu Zhang,Chong He,Wenbin Li
Vectran fabrics are widely employed as the key material for the manufacturing of stratospheric airship. Nonetheless, Vectran faber would decompose due to the UV aging during the prolonged flying process. Herein, atomic layer deposition (ALD) technology was introduced to coat TiO 2 nanolayers on the surface of Vectran fabrics. Titanium isopropoxide liquid was employed as the Ti source precursor throughout the deposition process. Compared with sol-gel vacuum infiltration technic, ALD modified Vectran yarns possessed higher surface uniformity, better UV blocking performance and lower density. Notably, thickness of the TiO 2 nanocoating prepared through the ALD method was adjustable, which can optimize the UV resistance of Vectran yarn without significantly affect its density. Additionally, the nanolayer interface can induce structural coloration on the Vectran strand via diffraction phenomena. These outstanding merits endow ALD technic a promising choice to modify the surface of Vectran fiber used as the skin of stratospheric airships.
The poly(vinyl acetate) (PVAc)/zinc oxide (ZnO) microcapsule and PVAc/titanium dioxide (TiO 2 ) microcapsule were synthesized via in-situ emulsion polymerization method. The PVAc/ZnO microcapsule and PVAc/TiO 2 microcapsule were characterized by fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis(TG), transmission electron microscopy (TEM), and UV-visible spectroscopy (UV-vis). Effect of PVAc/ZnO microcapsule and PVAc/TiO 2 microcapsule on properties of poly(lactic acid) (PLA) was evaluated by UV-vis, SEM and mechanical properties test. The results showed that the addition of PVAc/ZnO and PVAc/TiO 2 microcapsules as a UV-blocking additive could significantly enhance UV-blocking property of PLA/PVAc/ZnO microcapsule composites and PLA/PVAc/TiO 2 microcapsule composites compared with pure PLA, PLA/ZnO composites and PLA/TiO 2 composites. The mechanical properties of PLA/PVAc/ZnO microcapsule composites were better than those of PLA/ZnO composites due to good dispersability and compatibility of PVAc/ZnO microcapsule in PLA matrix. Also, the mechanical properties of PLA/PVAc/TiO 2 microcapsule composites were better than those of pure PLA and PLA/TiO 2 composites. This study demonstrates the great potentials of the intrinsically UV shield additive PVAc/ZnO and PVAc/TiO 2 microcapsules in the application of high performance matrix resin and composite material.
An ultraviolet shielding hydrogel of P(NaSS-co-MPTC)/TiO 2 was prepared by introducing TiO 2 nanoparticles (TiO 2 NPS) into polyampholyte matrix through photo-initiated radical copolymerization of cationic monomer of 3-(methacrylamide) propyltrimethylammonium chloride (MPTC) and anionic monomer of sodium 4-vinylbenzenesulfonate (NaSS) in the aqueous solution of sodium chloride (NaCl). FTIR, XPS, TEM, XRD, and SEM were used to characterize the morphology and structure of hydrogel of P(NaSS-co-MPTC)/TiO 2. The result showed that anatase TiO 2 NPS with the size about 15 ~ 20 nm were not just acted as ultraviolet shielding agent and general photo-initiator, they also could be crosslinked in polyampholyte matrix by hydrogen bonding between hydroxyl groups on the surface of TiO 2 NPS and sulfonate groups on the polymer chains. Based on two kinds of reversible weak bonds of hydrogen bond and ionic bond, the P(NaSS-co-MPTC)/TiO 2 hydrogel exhibited excellent mechanical properties and self-healing ability at ambient conditions, which will greatly increase its service life being a UV inhibitor.
Yongli Zhang,Chunlong Zuo,Xiaoyu Liu,Ziyin Ye,Wei Tan,Ping Li,Yuanlin Ren,Xiaohui Liu
Polyethylene terephthalate (PET) fibers are widely used in many fields, but their flammability and molten droplet characteristics during combustion pose a significant safety risk. To address the issue, a novel approach was developed to enhance the flame retardant and anti-dripping performances of PET fabric through a combination of dyeing and mussel-inspired strategy. First, PET fabric was directly dyed with heme chloride (HC) to produce dyed PET fabric (HC-PET), which was then treated by a mussel-inspired tannic acid-based flame retardant (TAPP) and an impregnation-drying-curing process to prepare flame retardant PET fabric (FR-PET). The results indicated that the total heat release (THR) and peak smoke production rate (PSPR) of FR-PET were decreased by 22.8 % and 49.7 %, respectively, and the limiting oxygen index (LOI) was increased from 21 % to 29.8 %, showing good flame retardant properties. Additionally, the UV resistance and antibacterial performances of FR-PET were also significantly improved. In summary, this study provided a feasible approach for the preparation of multifunctional PET textiles with dyeing, flame retardant, anti-dripping, UV resistance and antibacterial performances.
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