Natural Rubber 

I want some foam rubber. But of course most of it is plastic derived. Apparently there is such a thing as natural foam rubber. But first I had to do a bit more research into actual rubber. Heres what I found…..

There are two major categories of rubber; natural and synthetic. The most popular compounds are;

Natural Rubber
Vulcanised Rubber
Synthetic

History

Thousands of years BC Indians living in Central and South America were using latex to makewaterproof clothes and shoes using latex from rubber trees.

It was unknown in Europe until 1731when French explorer Charles Marie de La Condamine sent back samples of rubber to Europe. It was put to a variety of uses In 1770 Joseph Priestley found he could use pieces of rubber to erase pencil marks.

Others used it to waterproof cloth a series of discoveries that eventually led to Charles Macintosh inventing and patenting the rubberized, waterproof coat or macintosh. But it wasnt until 1839 when American inventor Charles Goodyear discovered how to vulcanize rubber that it really came into its own.

Natural Rubber

also called Latex or Para

Natural rubber is made from latex
Latex is the white liquid that oozes from certain plants when you cut into them.There are around 200 plants in the world that produce latex including dandilions.
99 percent of natural rubber comes from a tree called Hevea brasiliensis, or the rubber tree.

• Though it’s sometimes mistaken as the sap of the Hevea tree, latex actuality runs through ducts in a layer just outside the cambium below the tree’s bark.
• The rubber tree originates from South America.
• 90% of all natural rubber comes from these trees grown in rubber plantations mainly found in Indonesia, the Malay Peninsula and Sri Lanka.
• This type of rubber is often called Para rubber.

However by itself, unprocessed natural rubber is not all that useful. It tends to be brittle when cold and smelly and sticky when it warms up.

So it is combined with a range of addatives to give it added strength and flexibility.

The tough rubber used for tyres and such like has been further processed or vulcanised.

Vulcanised Rubber

Latex is filtered, washed, and reacted with acid to make the particles of rubber stick together.
Mastication machines “chew up” raw rubber using mechanical rollers and presses to make it softer, easier to work, and more sticky.
Addatives chemical ingredients are mixed in to improve its properties (for example, to make it more hardwearing).
Next, the rubber is squashed into shape by rollers (a process called calendering) or squeezed through specially shaped holes to make hollow tubes (a process known as extrusion).

Finally, the rubber is vulcanized (cooked): sulfur is added and the rubber is heated to about 140°C (280°F).

Biodegradable?

Latex when made from rubber trees a natural sounds like it should be biodegradable. Which has led to claims that that non-vulcanised products like latex condoms and other products  are.

This is hotly debated!
Most latex products contain addatives to make them (amongst other things) stronger. It all depends on wether they are biodegradable or not.

While many people say that simple rubber products people  do eventually decompose, (not proven),  it takes such a long time as to make any claims of biodegradability  misleading.Certainly the anti-balloon camp do not consider latex balloons to be biodegradable despite what the balloon industry say.

And yet this….

• Very thin rubber products, such as balloons and condoms, will degrade naturally especially if they are subjected to natural sunlight. As is evident from the problems which are associated with sealing rings natural rubber is capable of being biodegraded. It should be possible to compost thin rubber articles
• In a composting environment, biodegradation rates over 24 weeks were twice that compared to the fertilized treatment in soils. Degradation of natural rubber condoms in soil was slower compared to gloves with 42% of the initial weights remaining after 48 weeks. In contrast, the manufactured polyurethane condoms were hardly biodegradable.

Read more here

It is possible to buy natural latex foam rubber. For example
100% Natural Latex, Pure Comfort, Talalay rubber not foam, offering maximum comfort and luxury, available in Soft, Medium or Firm.read more here. I

and latex sheets like these

Both of the above have been described as biodegradable.

However vulcanised rubber generally is not. Though there are some suggestions that it may eventually biodegrade more research needs to be done.

Synthetic rubber on the other hand is definitely  not biodegradable.

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