Cellulosic fabrics modified with polyphosphonium chitosan hydrazone-TiO2-Ag nanobiocomposites for multifunctional applications.

Bionanocomposites (BNC1,2) of binary (PPCH-Ag) and ternary (PPCH-TiO2-Ag) (PPCH = polyphosphonium chitosan-hydrazone) have been synthesized and immobilized on cellulosic fabrics (CFs) using an environmentally friendly single-step in situ methodology. The results of FTIR, TGA, EDX, SEM, and TEM investigations showed that PPCH and its BNCs were successfully formed on the surface layer of fabrics. Moreover, the BNC2-coated cloth exhibited a superhydrophobic behavior as revealed from the values of water contact angle (WCA) 152.1° and slide angle (SA) 8.7°. The cytotoxicity experiments on epithelial cells confirmed the safety of treated fabrics for human cells. The antimicrobial capabilities of the BNCs-treated textiles were greatly enhanced, with a small preference for BNC1-coated fabric, as compared to the native or other treated fabrics. In contrast, the BNC2-coated fabric demonstrated the highest anti-UV protection capabilities as indicated by its great capacity to reduce the UV transmission (UV-A, 2.1 %; UV-B, 1.8 %) as well as its UPF value (49.2). The durability tests revealed the high resistance of BNC2-CF against harsh washing conditions and their acquired functions sustainability up to 20 washing cycles.

Effect of γ-rays on carboxymethyl chitosan for use as antioxidant and preservative coating for peach fruit.

Carboxymethyl chitosan (CMCS) was synthesized by alkylation of chitosan using monochloroacetic acid and characterized by FTIR and (1)H-NMR spectroscopies. Different molecular weights (Mws) of CMCS were prepared by radiation degradation of CMCS in the solution form at different irradiation doses. The structural changes and Mw of degraded CMCS were confirmed by UV-Vis, FTIR and GPC. The antioxidant activity of CMCS was evaluated using scavenging effect on DPPH radicals, reducing power and ferrous ion chelating activity assays. The antioxidant activity of CMCS enhanced with decreasing CMCS Mw. The possible practical use of CMCS as preservative coating for peach fruit by dipping treatment after 10 days of storage at ambient temperature was investigated. The CMCS with lower Mw had a good effect on delaying spoilage and decreasing malondialdehyde (MDA) content of peach fruits suggesting their possible use as antioxidant and preservative coating.