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In this research work, we propose a synergistic effect of a green crosslinker and cellulose nanomaterial on the crystallinity, viscoelastic, and thermal properties of starch nanocomposites. A disaccharide derivative was used as a bio crosslinker and nanofiber from pineapple leaf as a reinforcing phase for starch. Sucrose was oxidised using periodate, that can selectively oxidise the vicinal hydroxyl group of sucrose and form tetra aldehyde derivative. Crystallinity of films after crosslinking decreased with successive addition of crosslinker. The melting temperature of films increased because of formation of more dense structure after crosslinking. Morphological investigations were analysed by atomic force microscopy. Polymer chain confinement and mechanics were quantified. The crosslink densities of the films were calculated using two models, phantom model and affine model, using storage modulus data. By using very low amount of crosslinker and nanoreinforcement, the properties of thermoplastic starch were significantly improved., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Cellulose nanocrystals (CNCs) were surface modified by esterification in tetrahydrofuran (THF) at 25 °C using different catalysts and anhydrides bearing different alkyl side chain lengths. Unmodified and acetic anhydride (AcAnh)-modified CNCs were studied as potential nanofillers for linear low-density poly(ethylene) (LLDPE). Nanocomposites were prepared by melt processing. Determination of the size and size distribution of CNCs in the nanocomposites by SEM revealed an enhanced compatibility of the AcAnh-modified CNCs with the LLDPE matrix, since the average size of the aggregates of the modified CNCs (0.5⁻5 μm) was smaller compared to that of the unmodified CNCs (2⁻20 μm). Tensile test experiments revealed an increase in the nanocomposites' stiffness and strain at break-by 20% and up to 90%, respectively-at the CNC concentration of 5 wt %, which is close to the critical percolation concentration. Since the CNC nanofiller simultaneously reduced LLDPE crystallinity, the reinforcement effect of CNCs was hampered. Therefore, the molding temperature was increased to 120 °C, and, in this way, the greatest increase of the Young's modulus was achieved (by ~45%). Despite the enhanced compatibility of the AcAnh-modified CNCs with the LLDPE matrix, no additional effect on the mechanical properties of the nanocomposites was observed in comparison to the unmodified CNC.

Eco-friendly "green" nano composites were fabricated from potato starch and cellulose nanofibers from pineapple leaf. Nanocomposites of starch/cellulose nanofibers were prepared by solution mixing followed by casting. The investigation of the viscoelastic properties confirms starch macromolecular chain confinement around the nano scale cellulose surface, superior dispersion and very good interaction between thermoplastic starch and cellulose nanofibers. The degree of chain confinement was quantified. The chain confinement was associated with the immobilization of the starch macromolecular chains in the network formed by the nano-scale cellulose fibers as a result of hydrogen boding interactions. From the results, it was assumed that the starch glycerol system exhibits a heterogenous nature and cellulose nanofibers tend to move towards glycerol rich starch phase. Barrier properties also improved with the addition of nanofiller up to 3wt.% but further addition depreciated properties due to possible fiber agglomeration. The kinetics of diffusion was investigated and typical kinetic parameters were determined and found that the nanocomposites follow pseudo fickian behaviour. The outcome of the work confirms that the prepared nanocomposites films can be used as a swap for packaging applications., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

A new process for the production of nanocellulose from selected cellulose-containing natural materials has been developed. The liquefaction reaction, using glycols and mild acid catalysis (methane sulphonic acid), was applied to four model materials, namely cotton linters, spruce wood, eucalyptus wood and Chinese silver grass. The process contains only four steps, the milling, the glycolysis reaction, centrifugation and final rinsing with an organic solvent. The nanocrystalline cellulose recovery was between 56% and 75%. The crystallinity index was greater than that of the starting materials due to the liquefaction of lignin, hemicelluloses and amorphous cellulose. The final product was a stable, highly concentrated nanocrystalline cellulose suspension in the organic medium. The liquid residue, after the liquefaction of the cotton linters contained significant quantities of levulinic acid. Different sugars were identified in the liquid residues that were derived from cellulose and hemicelluloses during the liquefaction reaction., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Liquefied wood (LW) prepared in a microwave process was applied as a novel; inexpensive precursor feedstock for incorporation of ( R )-3-hydroxyvalerate (3HV) into polyhydroxyalkanoate (PHA) biopolyesters in order to improve the biopolyester's material quality; Cupriavidus necator was applied as microbial production strain. For proof of concept, pre-experiments were carried out on a shake flask scale using different mixtures of glucose and LW as carbon source. The results indicate that LW definitely acts as a 3HV precursor, but, at the same time, displays toxic effects on C. necator at concentrations exceeding 10 g/L. Based on these findings, PHA biosynthesis under controlled conditions was performed using a fed-batch feeding regime on a bioreactor scale. As major outcome, a poly(3HB- co -0.8%-3HV) copolyester was obtained displaying a desired high molar mass of M w = 5.39 × 10⁵ g/mol at low molar-mass dispersity ( Đ M of 1.53), a degree of crystallinity ( X c ) of 62.1%, and melting temperature T m (176.3 °C) slightly lower than values reported for poly([ R ]-3-hydroxybutyrate) (PHB) homopolyester produced by C. necator ; thus, the produced biopolyester is expected to be more suitable for polymer processing purposes.

In our research, we have utilized high energy ultrasound for the liquefaction of different lignocellulosic materials, wood wastes in particular. We developed a highly efficient way of transforming this biomass waste into valuable chemicals. It was found, that the reaction yield in all experiments was high and that the reaction times were shortened up to nine times when using the ultrasound process with smaller residual particles and with no influence on the hydroxyl number of the final products. The use of the ultrasound process inhibits the formation of the large molecular structures during the liquefaction from the degradation products, by keeping the reactive segments apart and due to such a short reaction time being used. The short reaction time and subsequent low energy consumption for the liquefaction reaction leads to the creation of the new method for the transformation of the wood waste materials into valuable chemicals., (Copyright © 2011 Elsevier Ltd. All rights reserved.)