Organic and Inorganic PCL-Based Electrospun Fibers.

Adrián Leonés,Daniel Lopez,Alicia Mujica-Garcia,Valentina Salaris,Marina Patricia Arrieta,Laura Peponi,José Maria Kenny

doi:10.3390/polym12061325

Abstract

In this work, different nanocomposite electrospun fiber mats were obtained based on poly(e-caprolactone) (PCL) and reinforced with both organic and inorganic nanoparticles. In particular, on one side, cellulose nanocrystals (CNC) were synthesized and functionalized by “grafting from” reaction, using their superficial OH– group to graft PCL chains. On the other side, commercial chitosan, graphene as organic, while silver, hydroxyapatite, and fumed silica nanoparticles were used as inorganic reinforcements. All the nanoparticles were added at 1 wt% with respect to the PCL polymeric matrix in order to compare the different behavior of the woven no-woven nanocomposite electrospun fibers with a fixed amount of both organic and inorganic nanoparticles. From the thermal point of view, no difference was found between the effect of the addition of organic or inorganic nanoparticles, with no significant variation in the Tg (glass transition temperature), Tm (melting temperature), and the degree of crystallinity, leading in all cases to high crystallinity electrospun mats. From the mechanical point of view, the highest values of Young modulus were obtained when graphene, CNC, and silver nanoparticles were added to the PCL electrospun fibers. Moreover, all the nanoparticles used, both organic and inorganic, increased the flexibility of the electrospun mats, increasing their elongation at break.

Highlights

Poly(ε-caprolactone) (PCL) is a biodegradable and biocompatible aliphatic polyester
In order to ensure the presence of PCL chains in cellulose nanocrystals (CNC)-g-PCL during the “grafting from” reaction, vibrational spectroscopies studies were conducted, comparing the results obtained from neat PCL and CNC with CNC grafted with PCL (Figure 1)
Summarizing, the values for the degree of crystallinity were quite similar, hindering a clear separation on the effect of the addition of organic or inorganic nanoparticles being strongly influenced by the high crystallinity of the neat Electruspun PCL fibers (ePCL) electrospun fiber mats—higher than 50%

Summary

Introduction

Poly(ε-caprolactone) (PCL) is a biodegradable and biocompatible aliphatic polyester. It offers a unique combination of polyolefin-like mechanical properties and polyester-like hydrolyzability [1,2], providing good compatibility with a wide range of other polymers in both blends and copolymer forms in order to tune its properties [3,4,5]. PCL is used as a polymeric matrix to obtain nanocomposites by adding micro and nanoparticles to improve its mechanical properties and its thermal stability [6], taking the advantage of the strong ability of PCL-based materials to be processed in different forms, such as bulk, films, and fibers, among others [7]. The electrospinning process, belonging to the Polymers 2020, 12, 1325; doi:10.3390/polym12061325 www.mdpi.com/journal/polymers

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Conclusion