Robust and nanoparticle-free superhydrophobic cotton fabric fabricated from all biological resources for oil/water separation.

Traditional superhydrophobic cotton fabrics (SCFs) for oil/water separation were usually fabricated by surface coating with inorganic nanoparticles combined with nonrenewable and nonbiodegradable or even toxic fossil-based chemicals, which would lead to secondary environmental pollution after their lifetime. In this study, we report robust, nanoparticle-free, fluorine-free SFC, which was prepared by acid etching followed by surface coating with epoxidized soybean oil resin (CESO) and subsequent modification with stearic acid (STA). No toxic compound and no nanoparticle were included within the SCF and all the raw materials including cotton fabric, CESO and STA are biodegradable and derived from biological resources. The SCF showed excellent mechanical stability and chemical/environmental resistances. The superhydrophobicity of the SFC survived from mechanical abrasion, tape peeling, ultrasonication, solvent erosion and low/high temperature exposure. The SCF also exhibited good acid/alkali resistance with contact angle over 150° toward different pH water droplets. Moreover, the SCF could efficiently separate oil/water mixtures with efficiency above 97.9% and the superhydrophobicity remained after reusing for at least 10 times. The fully biological-derived SCF with excellent mechanical and chemical resistances exhibit great potential for separation of oil/water mixtures.

Influence of ether linkage on the enzymatic degradation of PBS copolymers: Comparative study on poly (butylene succinate-co-diethylene glycol succinate) and poly (butylene succinate-co-butylene diglycolic acid).

The difference of enzymatic degradation behavior between Poly (butylene succinate-co-diethylene glycol succinate) (PBS-co-DEGS) and Poly (butylene succinate-co-butylene diglycolic acid) (PBS-co-BDGA) was studied in a Tetrahydrofuran (THF)/toluene mixed system by Novozym 435 (N435, immobilized Candida Antarctica lipase supported on acrylic resin) catalysis for 30 h. These two copolymers (modified with alcoholic acid by ether linkage) were synthesized by melt polycondensation and characterized by 1H NMR. The average molecular weight and thermal property before and after degradation were determined by gel permeation chromatography (GPC) and thermogravimetric analysis (TGA), respectively. Results revealed that end-chain degradation of DEG20 (20% content diethylene glycol of diols) and intramolecular random degradation of DGA20 (20% content diglycolic acid of diacids) both occurred at the same time from 0 h to 12 h. TGA curves show that after degradation by N435, the T-5% of both copolymers decreased from about 300 °C to below 210 °C. In degradation products (linear and cyclic oligomers, no monomer was appeared below 10 degree of polymerization. According to the molecular docking results, the free binding energy between PC lipase and substrate was in the order of BDGAB < DEGSDEG < BSDEG < BSB. Thus, the enzymatic degradability of PBS-co-DEGS is more effective than that of PBS-co-BDGA.