Nanocomposites with functionalised polysaccharide nanocrystals through aqueous free radical polymerisation promoted by ozonolysis. (1st January 2016)

• Record Type: Journal Article
• Authors: Espino-Pérez, E.; Gilbert, Robert G.; Domenek, S.; Brochier-Salon, M.C.; Belgacem, M.N.; Bras, J.
• Is Part Of: Carbohydrate polymers. Volume 135(2016)
• Page Start: 256
• Page End: 266
• Publication Date: 2016-01-01
• Subjects: AFM atomic force microscopy -- AGU anhydroglucose monomer unit -- CCD charge-coupled device -- CNC cellulose nanocrystalls -- CNCOOH CNC hydroperoxide -- CP/MAS cross-polarisation/magic angle spinning -- FEG-SEM field-emission gun scanning electron microscopy -- Ic crystallinity index -- I1, I2 two X-ray intensities -- IR infrared spectroscopy -- l film thickness -- MCC microcrystalline cellulose -- NMR nuclear magnetic resonance -- P permeability -- PLA poly(lactic acid) -- PSty polystyrene -- RH relative humidity -- S exchange surface area -- SNC starch nanocrystals -- SNCOOH SNC hydroperoxide -- Sty styrene monomer unit -- TGA thermogravimetric analysis -- TMS tetramethylsilane -- Wsl work of adhesion -- WVTR water vapour transmission rate -- XRD X-ray diffraction -- γlv liquid-vapour surface tension -- γsl solid-liquid surface tension -- γsv solid-vapour surface tension -- ΔP gradient for partial pressure of water -- θγ contact angle -- χc crystallinity index; Chemical modification -- Ozonolysis -- Radical polymerisation -- Polysaccharide nanocrystals -- Starch; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2015.09.005
• Languages: English
• ISSNs: 0144-8617

Abstract

Highlights: Starch and cellulose nanocrystals were functionalised with polystyrene. The grafting was initiated by ozone. SNC functionalisation was six times more efficient than that of CNC. Grafting with polystyrene improved thermal stability of polysaccharide nanocrystals. Water barrier properties of polylactide nanocomposites improved by 90%. Abstract: Cellulose nanocrystals (CNC) and starch nanocrystals (SNC) were grafted by ozone-initiated free-radical polymerisation of styrene in a heterogeneous medium. Surface functionalisation was confirmed by infrared spectroscopy, contact angle measurements, and thermogravimetric and elemental analysis. X-ray diffraction and scanning electron microscopy showed that there was no significant change in the morphology or crystallinity of the nanoparticles following ozonolysis. The grafting efficiency, quantified by 13 C NMR, was greater for SNC, with a styrene/anhydroglucose ratio of 1.56 compared to 0.25 for CNC. The thermal stability improved by 100 °C. The contact angles were 97° and 78° following the SNC and CNC grafting, respectively, demonstrating the efficiency of the grafting in changing the surface properties even at low levels of surface substitution. The grafting increased the compatibility with the polylactide, and produced nanocomposites with improved water vapour barrier properties. Ozone-mediated grafting is thus a promising approach for surface functionalisation of polysaccharide nanocrystals.