Orientation of cellulose nanocrystals in electrospun polymer fibres (dataset)

Dataset supporting the open access article.Polystyrene and poly(vinyl alcohol) nanofibres containing cellulose nanocrystals (CNCs) were successfully produced by electrospinning. Knowledge of the local orientation of CNCs in electrospun fibres is critical to understand and exploit their mechanical properties. The orientation of CNCs in these electrospun fibres was investigated using transmission electron microscopy (TEM) and Raman spectroscopy. A Raman band located at ~1095 cm−1, associated with the C–O ring stretching of the cellulose backbone, was used to quantify the orientation of the CNCs within the fibres. Raman spectra were fitted using a theoretical model to characterize the extent of orientation. From these data, it is observed that the CNCs have little orientation along the direction parallel to the axis of the fibres. Evidences for both oriented and non-oriented regions of CNCs in the fibres are presented from TEM images of nanofibres. These results contradict previously published work in this area and micromechanical modelling calculations suggest a uniform orientation of CNCs in electrospun polymer fibres. It is demonstrated that this explains why the mechanical properties of electrospun fibre mats containing CNCs are not always the same as that would be expected for a fully oriented system

The factorial structure of the supervisor’s core competencies scale

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Mercerized linters cellulose : characterization and acetylation in N,N-dimethylacetamide/lithium chloride

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Monitoring composition of LNAPL. Essential tool for the estimation of free LNAPL specific volumes

In an aquifer contaminated by LNAPLs, several types of LNAPL can been find with different composition and features, which influence its fate and transport in groundwater and the estimation of its volume. Over time, two different models have been developed for the free phase volume estimation: Pancake Model and Vertical Equilibrium Model. A sensitivity analysis has been carried out, using both models, to evaluate the influence of LNAPL type on volume estimation. This analysis has been carried out applying in every examined monitoring well the features of three different LNAPL types: gasoline, diesel and their mixtures. The results show a sensible variation of estimated specific volumes as LNAPL type varies. Hence, as it can been deduced, the knowledge of LNAPL type and its characteristics are fundamental for a reliable volume estimation. In addition, since the LNAPL type can change over the time, when a contaminated site is monitored for the evaluation of LNAPL volumes, it is fundamental observe during the time, not only the supernatant thickness in the well, but also the compounds constituting the LNAPL, through the sampling of supernatant and its analysis

Viscometric behaviour of polyelectrolytes in the presence of low salt concentration

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