Urea entrapment in cellulose acetate microparticles obtained by electrospraying
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ORIGINAL PAPER
Urea entrapment in cellulose acetate microparticles obtained by electrospraying Vanderlei Luis Sitta Severgnini1 · Andrés Felipe Chamorro Rengifo2 · Nito A. Debacher2 · Edson Minatti2 Received: 9 April 2020 / Accepted: 6 November 2020 © The Polymer Society, Taipei 2020
Abstract Urea is a widely used source of nitrogen, but its rapid solubilization in water leads to significant wastage on application. Thus, the quest for an efficient and economical polymeric matrix able to encapsulated urea is a long-standing challenge. In this paper, we present a simple and economical method for urea entrapment in cellulose acetate (CA) microparticles produced by the electrospraying process. The morphology and diameter of the microparticles were optimized experimentally by evaluating the solvent composition (binary mixture) and polymer concentration. The electrospraying process parameters, such as particle collection distance, applied voltage and flow rate, were also evaluated. The particle diameter was determined by scanning electron microscopy (SEM) and the CA microparticle characteristics, urea incorporation and in vitro release profile were determined by Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). The morphological characteristics (shape and porosity) of the CA microparticles were affected by the diffusion rate and CA solubility due to solvent evaporation in the electrospraying process. The SEM images showed monodispersed and spherical CA microparticles with a diameter size of 2.2 ± 0.3 µm. The FTIR spectra and SEM images verified the urea entrapment in the CA microparticles (100 mg/g), and the particle morphology did not appear to be affected. The release of urea from the CA microparticles showed a maximum of 79% after 7 h, which is a significant difference in relation to in vitro urea release. The results obtained using the electrospray technology represent a step forward in the search to improve the incorporation of urea into CA microparticles. Keywords Electrospraying · Urea · Microparticles · Cellulose acetate · Solvent mixtures
Introduction Urea has the chemical formula of CO(NH 2) 2 and is a diamide also known as carbamide. It is an organic compound obtained on a large scale employing the synthetic process developed by Bosch-Meiser in 1922.[1]. A wide variety of applications has been described and it is used in formulations for cosmetics and drugs, in the chemical industry as a raw material for resin production and in agrobusiness as * Vanderlei Luis Sitta Severgnini [email protected]; [email protected] http://polissol.sites.ufsc.br/ 1
Instituto de Ciências Exatas e Tecnologia, Universidade Federal do Amazonas, Itacoatiara, Amazonas, Brazil
Laboratório de Polímeros E Surfactantes, Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil
2
a supplement for ruminants [2]. However, most of the production is destined for use in nitrogen-release fertilizer [3]. Urea has a high
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