COMPOSTABLE PHA- polyhydroxyalkanoate (biopol): Biodegradable polymers that are produced by using bacteria to aid the fermenting plant sugers. They also break down when bacteria attacks the polymer.
properties: packaging for food and beauty, Medical fixtures like dissolvable fixatives films, screws, bone plates. slow release medication in capsules
one of the most common types from this family is called PHB - polyhdroxbutrate
properties: similar to PP
COMPOSTABLE PLA- polyactides:
- cellulose (made from plants)/ corn starch based polymers
- similar properties to polyethylene & PP, behaves like a thermoplastic.Can be tranperant and coloured.
- products: packaging, bottles, films carrier bags, gerdening product.
- medical: implants, sutures becuase it can dissolve over time, medicine capsules
Absorbable/ water soluble polymers
- These polymers dissolve when they come into contact with water. E.g. washing pouches for the washing machine or dish washer.In hospitals they may have bags for contain washing that dissolve once in the washing machine protecting the people handling the loads.
- Lactide, glycolide, based polymers by Lactel- Absorbable polymers.
- Used for medical devices and medical drug delivery.
Ecofilm (trade name)
- Similar to LDPE.
- 300% stronger.
- Breaks down when microorganisms like c02 or water attack it.
common uses: compost and rubbish bags, packaging for toys, films.
DEGRADABLE Oxo- degradable polymers:
- Have additives to promote short degradation e.g. the polymer will deteriorate in less than 5 years.
- The polymer breaks down into a POWDER from the EFFECTS of: heat, oxygen, moisture and mechanical stress.
- Conventional polymers can have additives added to them so they break down more easily e.g. PE,PP, PVC, PET, PS. They will take less time than the normal 100 years.
- photo-degradable polymers - break down when exposed to UV light.
- PHA BRAKE DOWN WHEN BACTERIA ATTACKS.
Biodegradable: a term given to materials that will break down with the aid of natural processes such as sunlight and rain.
Renewables: material that are extracted from managed sources, such as scandinavian pine taken from forests where trees are replaced by saplings as they are felled.