With the aim of exploring new materials and properties, we report the synthesis of a thermoplastic chain extended polyurethane membrane, with superior strength and toughness, obtained by incorporating two different concentrations of reactive cellulose nanocrystals (CNC) for potential use in kidney dialysis. Membrane nanocomposites were prepared by the phase inversion method and their structure and properties were determined. These materials were prepared from a polyurethane (PU) yielded from poly(1,4 butylene adipate) as a soft segment diol, isophorone diisocyanate (IPDI) and hexamethylenediamine (HMDA) as isocyanate and chain extender, respectively (hard segment), filled with 1 or 2% w/w CNC. Membrane preparation was made by the phase inversion method using N,N-dimethylformamide as solvent and water as nonsolvent, and subjected to dead-end microfiltration. Membranes were evaluated by their pure water flux, water content, hydraulic resistance and protein rejection. Polymers and nanocomposites were characterized by scanning electronic and optical microscopy, differential scanning calorimetry, infrared spectroscopy, strain stress testing and ¹³C solid state nuclear magnetic resonance. The most remarkable effects observed by the addition of CNCs are (i) a substantial increment in Young’s modulus to twenty-two times compared with the neat PU and (ii) a marked increase in pure water flux up to sixty times, for sample containing 1% (w/w) of CNC. We found that nanofiller has a strong affinity to soft segment diol, which crystallizes in the presence of CNCs, developing both superior mechanical and pure water flow properties, compared to neat PU. The presence of nanofiller also modifies PU intermolecular interactions and consequently the nature of membrane pores.

The design of nanocomposites with the potential for drug delivery is a topic of great interest. In this work, the synthesis of nanocomposites of poly(methacrylic acid) (PMAA) grafted onto carbon nanotubes (CNTs) functionalized with poly(amidoamine) (PAMAM) dendrimer by semicontinuous heterophase polymerization SHP, at three different methacrylic acid (MAA) dosing rates, is reported. SHP is a polymerization technique poorly used to prepare nanocomposites containing CNTs and has the potential to produce more ordered alkyl methacrylic polymer chains, which could favor the obtaining of a homogenous nanocomposite. For the nanocomposites synthesized, a lowest addition rate monomer-starved condition was reached. Analysis by X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA) demonstrate that functionalized CNTs are grafted onto the PMAA matrix. The ability of prepared nanocomposites to deliver hydrocortisone was evaluated by ultraviolet-visible spectroscopy (UV-Vis). The hydrocortisone release profiles of pure PMAA and of their nanocomposites prepared at the lowest monomer fed rate were fitted with Higuchi and Korsmeyer–Peppas models, successfully. Functionalized CNTs have a crucial role to induce an effective release of hydrocortisone from the prepared nanocomposites.