PVA supported catalytic membranes obtained by γ-irradiation for biodiesel production

Preparation and Characterization of Strongly Sulfonated Acid Block and Random Copolymer Membranes for Acetic Acid Esterification with 2-Propanol

In this paper, we report the synthesis of block and random copolymers of 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) and methyl methacrylate (MMA), with different AMPS feed ratios. These solution-processable copolymers with strongly sulfonated acid groups resulted in membranes with tunable ion exchange (IEC) and water absorption capacities. AFM images confirmed the microphase separation of PAMPS-b-PMMA-1:1 block copolymer membrane, annealed under the appropriate conditions. The resulting copolymers from the random combination of a 1:1 molar ratio of AMPS and MMA monomers are effective at enhancing the esterification conversion of acetic acid, when compared with a reaction catalyzed by PAMPS-b-PMMA block copolymers and the previously studied catalytic membranes. With the PAMPS-co-PMMA-1:1 membrane, the esterification reaction using acetic acid achieved 85% isopropyl acetate. These results are closely correlated with the increase in IEC (2.63 mmol H⁺g⁻¹) and the relationship between weight loss (20.3%) and swelling degree (68%) in 2-propanol.

Chitosan/Poly(vinylpyrrolidone) Matrices Obtained by Gamma-Irradiation for Skin Scaffolds: Characterization and Preliminary Cell Response Studies

Several studies have shown that chitosan possesses characteristics favorable for promoting dermal regeneration and accelerated wound healing. In this work we have reported the work that has been done on the development and characterization of biocompatible and biodegradable chitosan based matrices to be used as skin scaffolds. Poly(vinylpyrrrolidone) (PVP) was used as copolymer and a two steps methodology of freeze-drying and gamma irradiation was used to obtain the porous matrices. The influence of PVP content, synthesis procedure and absorbed radiation dose on matrices’ physical, chemical and structural properties was evaluated by ATR-FTIR, TGA, SEM, contact angle measurements and degradation behavior. The in vitro cellular viability and proliferation of HFFF2 fibroblast cell line was analyzed as a measure of matrices’ biocompatibility and ability to assist skin regeneration. Results show that over the studied range values, gamma-radiation dose, copolymer concentration and synthesis procedure can be used to tailor the matrices’ morphology in terms of porosity and surface roughness. Early results from biological assays evidence the biocompatibility of the prepared chitosan/PVP matrices since cells adhered to the surface of all matrices (chitosan/PVP (5%) γ-irradiated at 10 kGy presents the higher cellular viability). These features show that the resultant matrices could be a potential suitable scaffold for skin tissue regeneration.

Improvement of fuel properties of biodiesel with bioadditive ethyl levulinate

Biodiesel has poor cold flow properties due to their high saturated fatty acid content. Ethyl levulinate is used as bio-based cold flow improver additive in biodiesel. In this work, both ethyl levulinate and biodiesel were synthesized in the laboratory. Ethyl levulinate was added to the biodiesel at different rates, i.e, 5, 10, 15, 20 (vol %). The effect of ethyl levulinate addition on density, kinematic viscosity, acid value, cloud point and pour point was determined and compared to the EN 14214 and ASTM D6751 specification. Consequently, ethyl levulinate appears acceptable as a cold flow improver for biodiesel fuel.