Fossil-fuel-based insulation materials such as polyvinyl chloride (PVC), low-density polyethylene (LDPE), cross-linked polyethylene (XLPE) and ethylene-vinyl acetate (EVA) have dominated the electrical insulation industry at present.
Increased use of these polymers have caused a serious threat to environment causing, environ- mental pollution, global warming, and climate changes worldwide.
Biopolymers of- fers a solution to these problems, since they are fully renewable from bio-sources such as biomass, agricultural by-products, and biological waste.
In order to uti- lize biopolymers as an electrical insulation material, they should match or exceed electrical, mechanical, and thermal properties of their fossil-fuel-based counterparts.
Four bio-polymers namely polyhydroxy butyrate (PHB), poly(3-hydroxybutyrate-co- 3-hydroxyvalerate) (PHBV), poly (lactic acid) (PLA), cellulose acetate (CA) and three fossil-fuel-based synthetic polymers polycaprolactone (PCL), polybutylene suc- cinate (PBS), poly (butylene adipate-co-terephthalate) (PBAT) are selected based on their popularity in research and commercial availability.
Although commercial manu- facturing of these four synthetic polymers is from fossil-fuel-based sources, they can be synthesised from bio-sources as well.
Samples of six of these selected polymers, PHB, PHBV, PCL, PBS, and PBAT are obtained collaborating with the Biosystems En- gineering department for the electrical measurements.
These samples are thin films, prepared from spin-casting process.
Electrical properties such as complex dielectric constant, volume resistivity and AC electrical breakdown strength of these samples are measured, while thermal and mechanical properties are summarized from litera- ture.
Using experimental measurements and the literature data, properties of these selected polymers are compared with conventional polymers such as PVC, LDPE, XLPE and EVA.
Few biopolymers are shortlisted as possible candidate materials for electrical insulation applications.
The study was written by Lakshan Warnakulasooriya