Cork (material) Structure

Cork is an impermeable buoyant material, layers of bark tissue, harvested for commercial use primarily from the Quercus suber (cork oak) native to southwestern Europe and northwestern Africa.Cork is made from the hydrophobic substance cork.It is used in a variety of products, the most common of which is wine corks, due to its impervious, buoyant, elastic and flame-retardant properties. Portugal's montado landscape produces about half of the world's annual cork harvest, and Corticeira Amorim is the industry leader.Robert Hooke examined Cork under a microscope, which led him to discover and name the cell.Cork composition varies by geographic origin, climate and soil conditions, genetic origin, tree size, age (pristine or bred), and growing conditions.However, in general, cork consists of suberin (about 40% on average), lignin (22%), polysaccharides (cellulose and hemicellulose) (18%), extractables (15%), etc.

Structure

Cork exhibits a characteristic cellular structure in which the cells are usually pentagonal or hexagonal in shape.The cell wall consists of a thin lignin-rich middle layer (inner primary wall), a thick secondary wall consisting of alternating layers of suberin and wax, and a thin tertiary wall of polysaccharides.Some studies suggest that the secondary wall is lignified and thus may not consist solely of suberin and wax.The cork cells are filled with an air-like gas mixture that makes them behave like real "cushions", which contributes to the cork's ability to recover after compression.

Source

There are approximately 2,200,000 hectares of softwood forest worldwide; 34% in Portugal and 27% in Spain.The annual output is about 300,000 tons; 49.6% comes from Portugal, 30.5% from Spain, 5.8% from Morocco, 4.9% from Algeria, 3.5% from Tunisia, 3.1% from Italy, and 2.6% from France.Once the tree is about 25 years old, the corks are traditionally stripped from the trunk every nine years, with the first two harvests usually yielding lower quality corks.The lifespan of these trees is about 300 years.The cork industry is generally considered environmentally friendly.Cork production is generally considered sustainable because cork trees are not felled for cork; only the bark is stripped to harvest cork.The tree continued to live and grow.The sustainability of production and the easy recycling of cork products and by-products are two of its most distinctive aspects.Cork oak forests also protect against desertification and are a special habitat for the Iberian Peninsula and a refuge for various endangered species.

A carbon footprint study by Corticeira Amorim, France's Oeneo Bouchage and Portugal's Cork Supply Group concluded that cork is the most environmentally friendly wine stopper compared to alternatives.Corticeira Amorim's research, notably ("Life cycle analysis of cork, aluminum and plastic wine corks"), was developed by PricewaterhouseCoopers according to ISO 14040.The results concluded that in terms of greenhouse gas emissions, each plastic stopper released 10 times more carbon dioxide, while the aluminum screw cap released 26 times more carbon dioxide than cork stoppers.For example, producing 1,000 cork stoppers emits 1.5kg of CO2, but producing the same number of plastic stoppers emits 14kg of CO2 and producing the same number of aluminum screw caps emits 37kg of CO2.Cork oak is not related to the "cork tree" (Phellodendron), which has cork bark but is not used for cork production.