Marco Antonio Pérez-Castillo

Polymeric composite solutions (PCSs) reinforced with carbon nanotubes sponges (CNT-sponges) have attracted interest in material science and engineering due to their physicochemical properties. Understanding the influence of CNT-sponges content (0.1 wt.%, 0.3 wt.% and 0.5 wt.%) on rheological behavior of poly(styrene-co-acrylonitrile) P(S:AN) (0:100, 20:80, 40:60 and 50:50, wt.%:wt.%) solutions synthesized by emulsion polymerization can predict the viscoelastic parameters for their possible application in electrospinning processes. The obtained nanofibers can be used as sensors, textiles, purifying agents or artificial muscles and tissues. For this, amplitude and frequency sweeps were performed to measure the viscosity (η), storage (G’) and loss (G”) moduli and loss factor (tan δ). Most PCSs showed a shear thinning behavior over the viscosity range of 0.8 < η/Pa·s < 20. At low CNT-sponges concentration in the polymer matrix, the obtained loss factor indicated a liquid-like behavior, while as CNT-sponges content increases, the solid-like behavior predominated. Then, the polymeric solutions were successfully electrospun; however, some agglomerations were formed in materials containing 0.5 wt.% of CNT-sponges attributed to the interaction forces generated within the structure. Finally, the rheological analysis indicates that the PCS with a low percentage of CNT-sponges are highly suitable to be electrospun.

The influence of carbon nanotubes sponges (CNT–sponges) content at 0.1 wt.%, 0.3 wt.% and 0.5 wt.% on rheological properties of three series of polymeric solutions of poly (styrene-co-acrylonitrile) P(S:AN) was evaluated. For that, amplitude and frequency sweeps were made in order to determine the storage (G’) and loss (G’’) moduli, loss factor (tan δ), structural changes and homogeneity of polymeric composite solutions as function of polymeric content P(S:AN) 0:100, 20:80, 40:60 and 50:50 wt%:wt%. For polymeric composite solutions (PCS) of pristine polyacrylonitrile, the rheological measurements show a Newtonian behavior at low shear rates and non-Newtonian behavior at higher values, meanwhile, all copolymeric PCS perform a non-Newtonian (shear thinning) behavior with a viscosity range of 0.8 < η /Pa·s < 20. The loss factor indicates a liquid-like behavior for solutions with 0.1 wt.% and 0.3 wt.% of CNT–sponges content, meanwhile a solid-like behavior was observed for 0.5 wt.% concentration. Finally, the polymeric composite solutions were processed in an electrospinning system to obtain fibers and were analyzed by SEM technique, CNT-sponges agglomerations were found into fibers with 0.5 wt.% content. The aim of this rheological analysis was carried out to predict the viscoelastic parameters and the suitability of solutions to electrospun process.