Synthesis of Polyurethane Membranes Derived from Red Seaweed Biomass for Ammonia Filtration

The development of membrane technology is rapidly increasing due to its numerous advantages, including its ease of use, chemical resistant properties, reduced energy consumption, and limited need for chemical additives. Polyurethane membranes (PUM) are a particular type of membrane filter, synthesized using natural organic materials containing hydroxy (-OH) groups, which can be used for water filtration, e.g., ammonia removal. Red seaweed (Rhodophyta) has specific molecules which could be used for PUM. This study aimed to ascertain PUM synthesis from red seaweed biomass (PUM-RSB) by using toluene diisocyanate via the phase inversion method. Red seaweed biomass with a particle size of 777.3 nm was used as starting material containing abundant hydroxy groups visible in the FTIR spectrum. The PUM-RSB produced was elastic, dry, and sturdy. Thermal analysis of the membrane showed that the initial high degradation temperature was 290.71 °C, while the residue from the thermogravimetric analysis (TGA) analysis was 4.88%. The PUM-RSB section indicates the presence of cavities on the inside. The mechanical properties of the PUM-RSB have a stress value of 53.43 MPa and a nominal strain of 2.85%. In order to optimize the PUM-RSB synthesis, a Box–Behnken design of Response Surface Methodology was conducted and showed the value of RSB 0.176 g, TDI 3.000 g, and glycerin 0.200 g, resulting from the theoretical and experimental rejection factor, i.e., 31.3% and 23.9%, respectively.

Biocompatibility studies of polyurethane electrospun membranes based on arginine as chain extender

Electrospun polymers are an example of multi-functional biomaterials that improve the material-cellular interaction and aimed at enhancing wound healing. The main objective of this work is to fabricate electrospun polyurethane membranes using arginine as chain extender (PUUR) in order to test the fibroblasts affinity and adhesion on the material and the polymer toxicity. Polyurethane membranes were prepared in two steps: (i) the polyurethane synthesis, and ii) the electrospinning process. The membranes were characterized by scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy, gel permeation chromatography, and differential scanning calorimetry techniques. The evaluation of PUUR as a scaffolding biomaterial for growing and developing of cells on the material was realized by LIVE/DEAD staining. The results show that the fluorescent surface area of human fibroblasts (hFB), was greater in control dense membranes made from Tecoflex than in electrospun and dense PUUR. From SEM analysis, the electrospun membranes show relatively uniform attachment of cells with a well-spread shape, while Tecoflex dense membranes show a non-proliferating round shape, which is attributed to the fiber’s structure in electrospun membranes. The cell morphology and the cell attachment assay results reveal the well spreading of hFB cells on the surface of electrospun PUUR membranes which indicates a good response related to cell adhesion.