- Title
- An evaluation and comparison of the plasticiser effects of p -Menthane-3,8-diol-citronellal acetal plasticiser with triethyl citrate and bis(2-ethylhexyl) terephthalate on ethylcellulose films.
- Creator
- Marx, Johannes Scheepers
- Subject
- Plasticisers
- Date Issued
- 2019
- Date
- 2019
- Type
- Thesis
- Type
- Doctoral
- Type
- PhD
- Identifier
- http://hdl.handle.net/10948/44629
- Identifier
- vital:38164
- Description
- In recent years, much attention has been focused on research to replace petroleumbased commodity plastics, in a cost-effective manner, with biodegradable materials offering competitive mechanical properties. The use of natural and/or biodegradable plasticisers, with low toxicity and good compatibility with several plastics, resins, rubber and elastomers in substitution of conventional plasticisers, such as phthalates and other synthetic plasticisers attract the market along with the increasing worldwide trend towards the use of bio-polymers. The main research objective entailed the behaviour of the novel bio-plasticiser PMDcitronellal acetal (PMD-CA) and its comparison with other commercial bio-plasticiser, triethyl citrate (TEC) and a non-phthalate plasticiser bis(2-ethylhexyl) terephthalate (DOTP), on ethylcellulose (EC) films to evaluate whether it would be feasible to replace them with PMD-CA. The films were produced by a casting technique and were characterised by mechanical properties, thermoanalysis, Scanning Electron Microscopy, disintegration and Fourier-Transform Infrared (FT-IR) spectroscopy. The addition of any of the three plasticisers to EC film increased the flexibility of the films. The plasticisers PMD-CA and DOTP added to EC formed tougher films as compared to EC films containing TEC shown by the high % elongation at break, strain and displacement. Statistically, it was proved that PMD-CA and DOTP had a more significant effect on % elongation of EC films than TEC, postulated to be due to their similar molecular size and structure. Thermoanalytical studies conducted revealed that the thermal degradation process of EC films proceeded in three basic stages, namely dehydration, depolymerisation and pyrolytic decomposition. Thermoanalytical analysis showed that unplasticised EC films had a higher glass transition value compared to the films containing any of the plasticisers and that PMD-CA and DOTP are more effective plasticisers compared to TEC due to their lower glass transition temperatures. The presence of plasticisers in the polymer matrix did change the surface morphology of polymer films. The addition of hydroxypropyl methylcellulose (HPMC) to EC PMD-CA and EC DOTP films caused more significant globule-like bubbles which were not uniform in size on the surface of these films. Observations were made that the type of plasticiser coating with or without pore former influenced the disintegration properties of films. HPMC, as pore former, played a significant role in the drug release system matrix. EC PMD-CA and EC DOTP polymeric films controlled the disintegration of the films in the acidic and weakly acidic medium. EC and EC TEC films had less significant control on the disintegration rate of the acidic and weakly acidic disintegration media. FT-IR characterisation of the films revealed comparable peaks observed in all the polymer-plasticiser combinations and therefore it was concluded that chemical interactions did not exist between the polymers and plasticisers. Added excipients (plasticisers and pore formers) were found to be compatible with EC films. It was concluded within the scope of this research that EC films plasticised with PMDCA, DOTP or TEC outperformed film properties of those compared to unplasticised EC film. The plasticising properties of the novel bio-plasticiser PMD-CA are similar compared to DOTP, and superior to triethyl citrate and could therefore be considered as an effective bioplasticiser for enteric coating formulations in the pharmaceutical industry.
- Format
- xviii, 197 leaves
- Format
- Publisher
- Nelson Mandela University
- Publisher
- Faculty of Science
- Language
- English
- Rights
- Nelson Mandela University
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NMU School of BioMolecular and Chemical Sciences
| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | SOURCE1 | Marx, J 20380200 Thesis Dec 2019.pdf | 4 MB | Adobe Acrobat PDF | View Details Download |