Recycled Plastic Bottles
Recycled plastic bottles (maode of PET or Polyethyleneterephthalate) can be made into a flotation device capable of holding a massive amount of weight above water. Recycled bottles are extremely cheap and are more eco-friendly than most other building materials. This design has already been implemented on a small scale in the Spiral Island project.
Notes: Because PET is an excellent water and moisture barrier material, plastic bottles made from PET are widely used for soft drinks (see carbonation). For certain specialty bottles, such as those designated for beer containment, PET sandwiches an additional polyvinyl alcohol (PVOH) layer to further reduce its oxygen permeability.
Based on how it is processed, PET can be semi-rigid to rigid, and it is very lightweight. It makes a good gas and fair moisture barrier, as well as a good barrier to alcohol (requires additional "barrier" treatment) and solvents. It is strong and impact-resistant.
PET becomes white when exposed to chloroform and also certain other chemicals such as toluene. PET is hygroscopic, meaning that it absorbs water from its surroundings.
At least one species of bacterium in the genus Nocardia can degrade PET with an esterase enzyme.
Japanese scientists have isolated a bacterium Ideonella sakaiensis that possesses two enzymes which can break down the PET into smaller pieces that the bacterium can digest. A colony of I. sakaiensis can disintegrate a plastic film in about six weeks.