Nanocelluloses Reinforced Bio-Waterborne Polyurethane.

Piedad Gañán,Diana Marin,Pablo Marcelo Stefani,Verónica Mucci,M. E. Victoria Hormaiztegui,Mirta I. Aranguren

doi:10.3390/polym13172853

Abstract

The aim of this work was to evaluate the influence of two kinds of bio- nano-reinforcements, cellulose nanocrystals (CNCs) and bacterial cellulose (BC), on the properties of castor oil-based waterborne polyurethane (WBPU) films. CNCs were obtained by the acidolysis of microcrystalline cellulose, while BC was produced from Komagataeibacter medellinensis. A WBPU/BC composite was prepared by the impregnation of a wet BC membrane and further drying, while the WBPU/CNC composite was obtained by casting. The nanoreinforcement was adequately dispersed in the polymer using any of the preparation methods, obtaining optically transparent compounds. Thermal gravimetric analysis, Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, dynamical mechanical analysis, differential scanning calorimetry, contact angle, and water absorption tests were carried out to analyze the chemical, physical, and thermal properties, as well as the morphology of nanocelluloses and composites. The incorporation of nanoreinforcements into the formulation increased the storage modulus above the glass transition temperature of the polymer. The thermal stability of the BC-reinforced composites was slightly higher than that of the CNC composites. In addition, BC allowed maintaining the structural integrity of the composites films, when they were immersed in water. The results were related to the relatively high thermal stability and the particular three-dimensional interconnected reticular morphology of BC.

Highlights

IntroductionThe continuous growing global interest in reducing the environmental pollution has triggered and sustained the research and development of environmentally friendly polymeric materials to replace polymers of synthetic origin in different applications [1,2]
The continuous growing global interest in reducing the environmental pollution has triggered and sustained the research and development of environmentally friendly polymeric materials to replace polymers of synthetic origin in different applications [1,2].In particular, polyurethanes (PUs) have received much attention
Since PUs are soluble in organic chemicals, their traditional use as coatings and their preparation as thin self-standing films are associated with the release of volatile organic compounds (VOCs) into the atmosphere

Summary

Introduction

The continuous growing global interest in reducing the environmental pollution has triggered and sustained the research and development of environmentally friendly polymeric materials to replace polymers of synthetic origin in different applications [1,2]. They are versatile polymers that find applications in various fields in the form of elastomers, foams, matrices of structural composites, fibers, adhesives, coatings, etc. Since PUs are soluble in organic chemicals, their traditional use as coatings and their preparation as thin self-standing films are associated with the release of volatile organic compounds (VOCs) into the atmosphere. With the introduction of bio-based polyols in the market, the preparation of bio-based WBPUs has progressed with the aim of producing greener alternatives to traditional materials [4–7]

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