Photochemical Stability of a Cotton Fabric Surface Dyed with a Reactive Triphenodioxazine Dye

The paper describes the photochemical stability of a commercial triphenodioxazine dye (Reactive Blue_204) linked onto a cotton fabric. Preliminary studies have shown that as a result of irradiation, the dye and its photodegradation products can pass directly onto the skin under conditions that mimic human perspiration and cause side-effects. The cotton dyed fabric was photo irradiated at different time intervals. Standard methods were employed to evaluate the color strength at various levels of pH, temperature, dyeing contact time, and salt concentration. The influence of UV radiation at different doses (λ > 300 nm) on the structural and color modifications of the dyed cotton fabrics was studied. Structural modifications before and after irradiation were compared by applying FTIR, UV–Vis, and near infrared chemical imaging (NIR–CI) techniques. Color modifications were investigated with the CIELAB system. Color differences significantly increased with the irradiation dose. High irradiation doses caused changes in the dye structure.

Epoxy Coatings Based on Modified Vegetable Oils for Wood Surface Protection against Fungal Degradation

The study describes the curing and thermal behavior of a new castor oil maleic anhydride adduct/epoxy oils/5-Bromosalicylic acid coatings and their composites with wood. The epoxidized oils were flax and hemp. The kinetic parameters of the curing and thermal degradation processes were calculated. The resistance of the coated wood surfaces against Cladosporium cladosporioides, Aspergillus brasiliensis, and Penicillium chrysogenum was tested. Color changes, FT-IR and SEM were conducted before and after fungal attack. The decay resistance and color change of raw wood and wood treated samples against fungi was tested. Based on the color changes and according to ASTM D 2017, the decay resistance rating for covered samples was considered as "highly resistant". Chemical resistance and coating performance tests were also undertaken. The obtained results recommend the described materials for applications in wood protective coatings.

Novel bio-based flexible epoxy resin from diglycidyl ether of bisphenol A cured with castor oil maleate

A novel bio-based flexible epoxy resin from castor oil maleate and diglycidyl ether of bisphenol A was synthesized and its thermal and electrical properties were investigated.

Cellulose extraction from orange peel using sulfite digestion reagents

Orange peel (OP) was used as raw material for cellulose extraction. Two different pulping reagents were used, sodium sulfite and sodium metabisulfite. The effect of the main process parameters, sulfite agent dosage and reaction duration, on cellulose yield was investigated. A central composite rotatable design involving two variables at five levels and response surface methodology were used for the optimization of cellulose recovery. Other two invariable parameters were reaction temperature and hydromodulus. The optimum yields, referred to the weight of double extracted OP, were 40.4% and 45.2% for sodium sulfite and sodium metabisulfite digestions, respectively. The crude celluloses were bleached with hypochlorite and oxygen. The physicochemical characterization data of these cellulose materials indicate good levels of purity, low crystallinities, good whitenesses, good water retention and moderate molecular weights. According to these specific properties the recovered celluloses could be used as fillers, water absorbents, or as raw materials for cellulose derivatives.