Electrically-assisted supersonic solution blowing and solution blow spinning of fibrous materials from natural rubber extracted from havea brasilienses

Abstract

Natural rubber (NR) is one of the most-studied natural polymers in the world due to its inherent characteristics and excellent properties. This renewable polymer has been used in industrial production of a wide range of products, from aircraft tires to medical devices. In the present study two novel methods of NR fibrous mat formation are investigated and compared: the electrically-assisted supersonic solution blow technique (EASBS) and solution blow spinning (SBS). The influence of processing parameters on the formation, morphology, and physical properties of the NR fibers is explored using scanning electron microscopy (SEM), mechanical testing, mechanical dynamic analysis (DMA), and thermal analysis (DSC and TG/DTG). Furthermore, the effect of 10% phenolic resin (PHOH) admixture on the final properties of NR obtained by EASBS, SBS and films formed by casting was investigated. SEM analysis helped to optimize the production conditions for NR and NR-PHOH fibrous mats by both EASBS and SBS with a fiber diameter in the 2–4 µm and 20–40 µm ranges, respectively. As a result of a more uniform distribution of NR fibers forming soldering points, the EASBS specimens appeared to be stiffer than those obtained by SBS and casting, resulting in a lower strain and a higher stress at break. TG/DTG analysis revealed that the thermal profiles were the same for all specimens, with polyisoprene decomposition occurring between 350 and 450 °C, whereas the Raman spectrum revealed that the bands for NR and PHOH resin were superimposed, indicating that there is no chemical interaction between the materials. Overall, NR fibrous mats with and without PHOH formed via EASBS and SBS revealed good mechanical properties as well as thermal stability.