Injectable Polymer
| Supervisor: | Dr Yung Ngothai
Dr Richard Musgrove (SARDI) |
| Students: | Bridget McDowall
Kaiyun Wong |
Objectives
To develop and test an injectable polymer that could be used to implant marine
animals' tissue to form the basis of a tagging method. The material should have
the following properties:
- Non - toxic
- Non - degradable (for at least 2 years)
- Harden into a solidified sphere when injected
- Injected at room temperature or within the range of tolerance of the marine
animal
Project Background:
Marine animals can be identified by natural markings, or by applying tags and
brands. The tagging of marine animals is important to marine biologists as it
provides information on stock identity, movements and migration, abundance, age
and growth, mortality and behaviour. By doing so, this would allow a more effective
management of fisheries and allow marine biologists to have a better knowledge
of the diversity, abundance and distribution of the population as a whole. The
emerging interest in polymer science has led to the development of tagging methods
which utilise this new technology. This project focuses on the development of
a polymer/solvent formulation for the tagging of Abalone.
Experimental
Research and previous works concluded using Polymethylmethacrylate (PMMA) as the
polymer. Chloroform, Ethanol and Tetrahydrofuran (THF) as possible solvents were
experimented and their concentrations varied. PMMA was first dissolved in the
solvent mixture and the resultant polymer mix was injected into various mediums
using a hypodermic syringe. The mediums that were used to model the marine animal's
body were 0.6 M salt solution, 2% CMC solution and chicken breast.
Results
Figure 1.1 Polymer mix when injected into 2% CMC
Three sets of experiments were carried out, using different solvents in varying
combinations and concentrations.
In set 1, it was found that a THF/PMMA solution dispersed in 0.6M salt solution.
As such, it was concluded that THF was not a suitable solvent. Experiments with
chloroform and ethanol were more successful.
In set 2, chloroform and ethanol mixtures were studied extensively. The most promising
results were obtained with 2.5g of PMMA and 1ml each of chloroform and ethanol.
This combination resulted in a solid, spherical polymer. All experiments were
conducted in a 0.6M salt solution.
In set 3, injection method and injection medium were studied. The solution was
injected into 2% CMC solution and chicken breast. Previously, problems had been
encountered with the large solids content of the mixture. This was overcome with
the use of a larger needle (approximately 1.5mm ID). It was believed that the
best injection position was through the Abalone's respiratory holes, through to
the animal's gonad.
Conclusions and Recommendations
- The formulation that was developed met 3 of the 4 requirements.
- The polymer can be injected into the animal at room temperature.
- The polymer hardened into a solidified sphere, within 24 hours.
- The polymer is non-degradable for at least two years.
- Final solvent composition was of 50-50vol% Chloroform and Ethanol (1ml each)
mixed with 2.5g of PMMA.
- The toxicity of the polymer could not be determined. This will require trials
on the Abalone.
- More research work has to be done to ensure that the non-toxic objective is
met.
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