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Incorporation of polysaccharide nanowhiskers into a poly(ethylene-co-vinyl alcohol) matrix
| Content Provider | Semantic Scholar |
|---|---|
| Author | Toit, Du Leonore, Madeleine |
| Copyright Year | 2013 |
| Abstract | The main aim of this study was to use poly (ethylene-co-vinyl alcohol) (EVOH) as vehicle to incorporate nanofillers into low density polyethylene (LDPE). For this purpose, chitin and cellulose nanowhiskers were prepared through a process of acid hydrolysis and then incorporated into different EVOH copolymers with varying ethylene contents by means of two different experimental methods, namely solution casting and electrospinning. The extremely small dimensions of nanowhiskers make it difficult to observe the degree of dispersion in the electrospun fibers using methods such as transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Fluorescence microscopy was therefore investigated as an alternative characterization technique to obtain better results with regard to tracking the filler dispersion. TEM analysis proved to be the most successful method for observing the dispersion of nanowhiskers for solution cast EVOH nanocomposites as well as electrospun EVOH nanocomposites. Clear differences between EVOH composites with low nanowhisker and high nanowhisker loading were observed in TEM images for these nanocomposites. Thermal analysis of solution cast as well as electrospun fibers were carried out using techniques such as differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). These results revealed changes in crystallization behaviour as well as changes in thermal stability of the EVOH nanocomposites compared to the pure polymer matrix. The incorporation of cellulose and chitin nanowhiskers indicated a general increase in percentage crystallization which probably resulted from the nanowhiskers acting as nucleating agents and therefore increasing the crystallization of most EVOH nanocomposites. The thermal stability is observed to increase as the cellulose nanowhisker loading is increased. This increase in thermal stability proved to be partly attributed to the presence of sulphuric acid which were not completely removed during dialysis of cellulose nanowhiskers. Neutralisation of cellulose nanowhiskers and the treatment with a strong base was therefore further investigated to improve degradation within the EVOH nanocomposites during thermal treatment. The last step in this study involved the incorporation of electrospun EVOH nanofibers containing cellulose nanowhiskers into LDPE in order to improve the mechanical properties. The tensile strength and Young’s modulus of these LDPE nanocomposites were seen to improve quite significantly while a decrease in elongation at break was observed. Stellenbosch University http://scholar.sun.ac.za |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://scholar.sun.ac.za/bitstream/handle/10019.1/80312/dutoit_incorporation_2013.pdf;jsessionid=EE57F20F71BDF123B1AF267981DE0F46?sequence=1 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
