Cork properties


The bark of the cork oak tree has a unique honeycomb structure composed of tiny cells. Each cell has the form of a 14-sided polyhedron and the inner cell space is entirely filled with an air-like gaseous mixture. The properties of cork derive naturally from the structure and chemical composition of its extremely strong, flexible cell membranes, which are waterproof and airtight.
Because about 89% of the tissue of the bark consists of gaseous matter, the density of cork is extremely low, in the order of 0.12 to 0.20, a fact that bears witness to the huge disproportion between the volume and the weight of the material.

The unique and valuable properties of cork include:

Lightness Lightness:
Cork is light and floats on water. For many thousands of years, this has been its most evident and most celebrated characteristic. Since ancient times, cork has been used in fishing equipment.		  
Elasticity Elasticity and Resiliency:
The cell membranes of cork are highly flexible, making it both compressible and elastic. This means it returns to its original shape after being subjected to pressure. This and other characteristics explain why cork has become an indispensable material for making bottle stoppers.
These physical qualities mean that cork can be fitted perfectly against the walls of the bottleneck. When cork is subjected to strong pressure, the gas in the cells is compressed and considerably reduced in volume. When the pressure is released, the cork immediately recovers its original shape and volume, showing no trace of having been subjected to any appreciable deformation.		  
Impermeability Impermeability:
The presence of suberin (a complex mixture of fatty acids and heavy organic alcohol) renders cork impermeable to both liquids and gases. As a result, it does not rot, making it one of the best seals available.		  
Insulation and fire retardant qualities Insulation and fire retardant qualities:
The value of cork is further enhanced by its low conductivity of heat, sound and vibration. This is because the gaseous elements it contains are sealed in tiny, impermeable compartments, insulated from each other by a moisture-resistant material. This endows cork with one of the best insulating capacities, both thermal and acoustic, of any natural substance.
Cork is also a natural fire retardant: it neither spreads flames nor releases toxic gases during combustion.		  
Resistance Resistance to wear:
Cork is remarkably resistant to wear and has a high friction coefficient. Thanks to its honeycomb structure, it is less affected by impact or friction than other hard surfaces.		  
Hypoallergenic properties

Hypoallergenic properties:
Because cork does not absorb dust, it helps protect against allergies and does not pose a risk to asthma sufferers. It also has an unchangeable constitution that guarantees efficiency.