I Can’t Sleep - Natural Rubber | Relaxing Bedtime Reading for Sleep
Episode Date: November 27, 2021Drift off with this calm bedtime reading on natural rubber, created to bring peace and ease insomnia. Benjamin’s soothing cadence explores how rubber is harvested from latex, its fascinating history... of use in industry and daily life, and its role in shaping the modern world. This is not whispering or hypnosis—just gentle, fact-filled narration to quiet the mind, reduce stress, and support restful sleep. Learn while you relax, and let the steady rhythm of Benjamin’s voice guide you into dreams. Press play, close your eyes, and drift into deep rest. Want More? Request a Topic: https://www.icantsleeppodcast.com/request-a-topic Ad-Free Episodes: https://icantsleep.supportingcast.fm/ Shop Sleep-Friendly Products: https://www.icantsleeppodcast.com/sponsors Join the Discussion on Discord: https://discord.gg/myhGhVUhn7 This content is derived from the Wikipedia article on Natural Rubber, available under the Creative Commons Attribution-ShareAlike (CC BY-SA) license. Read the full article: Wikipedia – Natural Rubber. Happy sleeping! Learn more about your ad choices. Visit megaphone.fm/adchoices
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Welcome to the I Can't Sleep Podcast, where I read random articles from across the web to bore you to sleep with my soothing voice.
I'm your host, Benjamin Boster. Today's episode is from a Wikipedia article titled Rubber.
Rubber, also called India rubber, latex, Amazonian rubber, Koucho or Kauchuk, is initially produced,
consists of polymers of the organic compound isoprene, with minor impurities of other organic
compounds.
Thailand and Indonesia are two of the leading rubber producers, types of polyisoprene that are used
as natural rubbers are classified as elastomers.
Currently, rubber is harvested mainly in the form of the latex from the rubber tree or others.
The latex is a sticky, milky, and white colloid drawn off by making incisions in the bark
and collecting the fluid in vessels in a process called tapping.
The latex then is refined into rubber that is ready for commercial processing.
In major areas, latex is allowed to coagulate in the collection cup.
The coagulated lumps are collected and processed into dry forms for sale.
Natural rubber is used extensively in many applications and products,
either alone or in combination with other materials.
In most of its useful forms, it has a large stretch ratio and high resilience,
and also is waterproof.
Industrial demand for rubber-like materials began to outstrip natural rubber supplies by the end of the 19th century,
leading to the synthesis of synthetic rubber in 1909 by chemical means.
Varieties
Amazonian Rubber Tree
The major commercial source of natural rubber latex is the Amazonian rubber tree,
a member of the Spurge family.
This species is preferred because it grows well under cultivation.
A properly managed tree responds to wounding by producing more latex for several years.
Congo rubber.
Congo rubber, formerly a major source of rubber, came from vines in the genus Landlvia.
Dandelion
Dandelion milk contains latex.
The latex exhibits the same quality as the natural rubber.
from rubber trees. In the wild types of dandelion, latex content is low and varies greatly. In Nazi Germany,
research projects tried to use dandelions as a base for rubber production, but failed. In 2013,
by inhibiting one key enzyme and using modern cultivation methods and optimization techniques,
Scientists in the Fronhofer Institute for Molecular Biology and Applied Ecology, IME, in Germany, developed a cultivator of the Russian dandelion that is suitable for commercial production of natural rubber.
In collaboration with continental tires, IME began a pilot facility.
Other
Many other plants produce forms of latex rich and isoprene polymers, though not all produce, you.
usable forms of polymer as easily as the para.
Some of them require more elaborate processing to produce anything like usable rubber,
and most are more difficult to tap.
Some produce other desirable materials, for example,
Kadapercha and Chikl from Manikara species.
Others that have been commercially exploited, or at least showed promise as rubber sources,
include the rubber fig, Panama Rubber Tree, various spurges, lettuce, the related Scorzonera Tao Zagis,
various taraxicum species, including common dandelion and Russian dandelion,
and perhaps most importantly for its hypoallergenic properties, Guayul.
The term gum rubber is sometimes applied to the tree-obtained version of natural rubber,
in order to distinguish it from the synthetic version.
History
The first use of rubber was by the indigenous cultures of Mesoamerica.
The earliest archaeological evidence of the use of natural latex from the heavier tree
comes from the Olmec culture,
in which rubber was first used for making balls for the Mesoamerican ballgame.
Rubber was later used by the Maya and Aztec cultures,
in addition to making balls
Aztecs used rubber for other purposes,
such as making containers
and to make textiles waterproof
by impregnating them with the latex sap.
Charles Marie de la Condominé is credited with introducing
samples of rubber to the Academy Royale de Science
of France in 1736.
In 1751, he presented a paper by Francois-Fresno
to the Academy.
that described many of rubber's properties.
This has been referred to as the first scientific paper on rubber.
In England, Joseph Priestley in 1770
observed that a piece of the material was extremely good
for rubbing off pencil marks on paper, hence the name rubber.
It slowly made its way around England.
In 1764, Francois Fresno discovered that turpentine was a rubber solvent.
Giovanni Fabroni is credited with the discovery of Nathza as a rubber solvent in 1779.
Charles Goodyear redeveloped volcanization in 1839, although Mesoamericans had used
stabilized rubber for balls and other objects as early as 1600 BC.
South America remained the main source of latex rubber used during much of the 19th century.
The rubber trade was heavily controlled by business.
this interest, but no laws expressly prohibited the export of seeds or plants.
In 1876, Henry Wickham smuggled 70,000 Amazonian rubber tree seeds from Brazil, and delivered
them to Q Gardens, England. Only 2,400 of these germinated.
Seedlings were then sent to India, British, Ceylon, Sri Lanka, Dutch East Indies, Indonesia,
Singapore, and British Malaya.
Malaya, now peninsular Malaysia, was later to become the biggest producer of rubber.
Pre-World War II.
Before World War II, significant uses included door and window profiles, hoses, belts,
gaskets, matting, flooring, and dampeners, anti-vibration mounts, for the automotive industry.
The use of rubber in car tires in particular consumed a significant amount of rubber.
Gloves, medical, household, and industrial, and toy balloons were large consumers of rubber,
although the type of rubber used is concentrated latex.
Significant tonnage of rubber was used as adhesives in many manufacturing industries and products,
although the two most noticeable were the paper and carpet.
industries. Rubber was commonly used to make rubber bands and pencil erasers. Rubber produced as a fiber,
sometimes called elastic, had significant value to the textile industry because of its excellent
elongation and recovery properties. For these purposes, manufactured rubber fiber was made as either
an extruded round fiber or rectangular fibers cut into strips from extruded film. Because of
of its low dye acceptance, feel, and appearance. The rubber fiber was either covered by yarn of
another fiber or directly woven with other yarns into the fabric. Rubber yarns were used in
foundation garments. While rubber is still used in textile manufacturing, its low latency limits
its use in lightweight garments because latex lacks resistance to oxidizing agents and is damaged by
aging, sunlight, oil, and perspiration.
The textile industry turned to neoprene, polymer of chloroprene, a type of synthetic rubber,
as well as another more commonly used elastomer fiber spandex, also known as elasting,
because of their superiority to rubber in both strength and durability.
Properties
Rubber exhibits unique physical and chemical properties.
Rubber's stress-strain behavior exhibits the Mullins effect and the pain effect, and is often modeled as hyperelastic.
Rubber strain crystallizes. Due to the presence of weakened allelic CH bonds in each repeat unit,
natural rubber is susceptible to vulcanization as well as being sensitive to ozone cracking.
The two main solvents for rubber are turpentine and naphtha petroleum.
Because rubber does not dissolve easily, the material is finely divided by shredding prior to its immersion.
An ammonia solution can be used to prevent the coagulation of raw latex.
Rubber begins to melt at approximately 180 degrees Celsius.
Elasticity
On a microscopic scale, relaxed rubber is a disorganized cluster of erratically changing wrinkled chains.
In stretched rubber, the chains are almost linear.
The restoring force is due to the preponderance of wrinkled conformations over more linear ones.
Cooling below the glass transition temperature permits local conformational changes,
but a reordering is practically impossible because of the larger energy barrier
for the concerted movement of longer chains.
Frozen rubber's elasticity is low,
and strain results from small changes of bond lengths and angles.
This caused the Challenger disaster
when the American space shuttle's flattened O-rings failed
to relax to fill a widened gap.
The glass transition is fast and reversible.
The force resumes on heating.
The parallel chains of stretched rubber are susceptible to crystallization.
This takes some time because turns of twisted chains
have to move out of the way of growing crystallites.
Crystallization has occurred, for example, when, after days, an inflated toy balloon is found
withered at a relatively large remaining volume. Where it is touched, it shrinks because the
temperature of the hand is enough to melt the crystals. Vulcanization of rubber creates dye
and polysulfide bonds between chains, which limits the degree of freedom and results in chains
that tighten more quickly for a given strain, thereby increasing the elastic force constant
and making the rubber harder and less extensible. Maloader
raw rubber storage deposits and rubber processing can produce malodure that is serious
enough to become a source of complaints and protest to those living in the vicinity.
Microbial impurities originate during the processing of block rubber.
These impurities break down during storage or thermal degradation and produce volatile organic compounds.
Examination of these compounds using gas chromatography mass spectrometry,
and gas comitography indicates that they contain sulfur, ammonia, alkenes, ketones, esters, hydrogen,
sulfide, nitrogen, and low molecular weight fatty acids.
When latex concentrate is produced from rubber, sulfuric acid is used for coagulation.
This produces malodorus hydrogen sulfide.
The industry can mitigate these bad odors with scrubber systems.
Chemical makeup
Latex is the polymer CIS1, 4 polyisoprene,
with a molecular weight of 100,000 to 1 million Dalton's.
Typically a small percentage, up to 5% of dry mass, of other materials such as proteins,
fatty acids, resins, and inorganic materials, salts, are found in natural rubber.
Polyisoprene can also be created synthetically, producing what is sometimes referred to as a synthetic
natural rubber, but the synthetic and natural routes are distinct.
Some natural rubber sources such as gutapurcha are composed of trans 1 or polyisoprene,
a structural isomer that has similar properties.
Natural rubber is an elastomer and a thermoplastic.
Once the rubber is vulcanized, it is a thermosid.
Most rubber and everyday use is vulcanized to a point where it shares properties of both,
i.e. if it is heated and cooled, it is degraded but not destroyed.
The final properties of a rubber item depend not just on the polymer, but also on modifiers and fillers, such as carbon black, fictus, whiting, and others.
Biosynthesis
Rubber particles are formed in the cytoplasm of specialized latex-producing cells called latissifers within rubber plants.
rubber particles are surrounded by a single phospholipid membrane with hydrophobic tails pointed inward.
The membrane allows biosynthetic proteins to be sequenced at the surface of the growing rubber particle,
which allows new monomeric units to be added from outside the biomebrane, but within the lactosifer.
The rubber particle is an enzymatically active entity that contains three layers of,
material, the rubber particle, a biomembrain, and free monomeric units.
The biomembrain is held tightly to the rubber core due to the high negative charge
along the double bonds of the rubber polymer backbone. Free monomeric units and conjugated proteins
make up the outer layer. The rubber precursor is isopentanyl pyrophosphate and allilic compound,
which elongates
by MG2 plus dependent condensation by the action of rubber transferase.
The monomer adds to the pyrophosphate end of the growing polymer.
The process displaces the terminal high-energy pyrophosphate.
The reaction produces a cis polymer.
The initiation step is catalyzed by prinal transferase,
which converts three monomers of isopentanyl pyrophosphate.
into Farnacil pyrophosphate.
The Farnacil pyrophosphate can bind the rubber transferase to elongate a new rubber polymer.
The required isopentanyl pyrophosphate is obtained from the mevalinate pathway,
which derives from the acetyl COA in the cytosol.
In plants, isoprene pyrophosphate can also be obtained from the 1-deox-Zulose.
Zulose, 5-phosphate, 2-C-methyl-D-arithridal, 4-phosphate pathway within plasmids.
The relative ratio of the Farnasal pyrophosphate initiator unit and isoprenov pyrophosphate
elongation monomer determines the rate of new particle synthesis versus elongation of existing particles.
The rubber is known to be produced by only one enzyme.
Extracts of latex host numerous small molecular weight proteins with unknown function.
The proteins possibly serve as cofactors as the synthetic rate decreases with complete removal.
Production
More than 28 million tons of rubber were produced in 2017.
of which approximately 47% was natural.
Since the bulk is synthetic, which is derived from petroleum,
the price of natural rubber is determined to a large extent
by the prevailing global price of crude oil.
Asia was the main source of natural rubber,
accounting for about 94% of output in 2005.
The three largest producers, Thailand, Indonesia, and Malaysia.
Together account for around 72% of all natural rubber protection.
Natural rubber is not cultivated widely in its native continent of South America,
due to the existence of South American leaf blight and other natural predators.
Cultivation
Rubber latex is extracted from rubber trees.
The economic life period of rubber trees in plantation is around 32 years,
up to seven years of immature phase and about 25 years of productive phase.
The soil requirement is well-drained weathered soil consisting of laterite, lateritic types,
sedimentary types, non-lateritic, red, or alluvial soils.
The climatic conditions for optimum growth of rubber trees are rainfall of around 250 centimeters,
evenly distributed without any marked dry season, and with at least 100 rainy days per year.
Temperature range of about 20 to 34 degrees Celsius, with a monthly mean of 25 to 28 degrees Celsius.
Atmospheric humidity of around 80 percent, about 2,000 hours sunshine per year at the rate of 6 hours per day throughout the year.
absence of strong winds. Many high-yielding clones have been developed for commercial planting.
These clones yield about 2,000 kilograms per hectare of dry rubber per year under ideal conditions.
Collection
In places such as Kerala and Sri Lanka, where coconuts are in abundance, the half-shell of coconut was used as the latex collection container.
glazed pottery or aluminum or plastic cups became more common in Karela India and other countries.
The cups are supported by a wire that encircles the tree.
This wire incorporates a spring so it can stretch as the tree grows.
The latex is led into the cup by a galvanized spout knocking into the bark.
Tapping normally takes place early in the morning.
when the internal pressure of the tree is highest.
A good tapper can tap a tree every 20 seconds on a standard half spiral system,
and a common daily task size is between 450 and 650 trees.
Trees are usually tapped on alternate or third days,
although many variations in timing, length, and number of cuts are used.
Tappers would make a slash in the bark with a small hatchet.
These slanting cuts allowed latex to flow from ducts located on the exterior
or the inner layer of bark, cambium of the tree.
Since the cambium controls the growth of the tree, growth stops if it is cut.
Thus, rubber tapping demanded accuracy
so that the incisions would not be too many given the size of the tree or too deep.
which could stunt its growth or kill it.
It is usual to tap a panel at least twice,
sometimes three times during the tree's life.
The economic life of the tree depends on how well the tapping is carried out,
as the critical factor is bark consumption.
A standard in Malaysia for alternate daily tapping is 25 centimeters vertical bark consumption per year.
The latex containing tubes in the bark is sent.
end in a spiral to the right. For this reason, tapping cuts usually ascend to the left to cut more tubes.
The trees drip latex for about four hours, stopping as latex coagulates naturally on the tapping cut,
thus blocking the latex tubes in the bark. Tappers usually rest and have a meal after finishing
their tapping work and then start collecting the liquid field latex at about midday.
Field coagula
The four types of earth coagula are a cup lump, tree lace, small holders lump, and earth scrap.
Each has significantly different properties.
Some trees continue to drip after the collection leading to a small amount of cup lump that is collected at the next tapping.
The latex that coagulates on the cut is also collected as tree lace.
Tree lace and cup lump together account for 10% to 20% of the dry rubber produced.
Latex that drips onto the ground, earth scrap, is also collected periodically for processing of low-grade product.
Cup lump
Cup lump is the coagulated material found in the collection cup when the taper next visits the tree to tap it again.
It arises from latex clinging to the walls of the cup after the latex was last poured into the bucket,
and from late dripping latex exuded before the latex carrying vessels of the tree become blocked.
It is of higher purity and of greater value than the other three types.
Cup lumps can also be used to describe a completely different type of coagulate that has collected in small holder plantations,
over a period of one to two weeks.
After tapping all of the trees,
the tapper will return to each tree
and stir in some type of acid,
which allows the newly harvested latex
to mix with the previously coagulated material.
The rubber acid mixture is what gives rubber plantations,
markets, and factories a strong odor.
Tree lace.
Tree lace is the coagulum strips
that the tapper peels off the previous cut before making a new cut.
It usually has higher copper and manganese contents than cup lump.
Both copper and manganese are pro-oxidants and can damage the physical properties of the dry rubber.
Smallholders lump
Smallholders lump is produced by smallholders who collect rubber from trees far from the nearest factory.
Many Indonesian smallholders who farm patties in remote areas
tap dispersed trees on their way to work in the paddy fields and collect latex
or as a coagulated latex on their way home.
As it is often impossible to preserve the latex sufficiently
to get it to a factory that processes latex in time for it to be used
to make high-quality products,
and as a latex would anyway have coagulated by the time
it reached the factory. A small holder will coagulated by any means available and any container available.
Some small holders use small containers, buckets, etc. But often the latex is coagulated in holes in the ground,
which are usually lined with plastic sheeting. Acidic materials and fermented fruit juices
are used to coagulate the latex, a form of assisted biological coaxioling.
population. Little care is taken to exclude twigs, leaves, and even bark from the lumps that are formed,
which may also include tree lace. Earth scrap. Earth scrap is material that gathers around the base of the tree.
It arises from latex overflowing from the cut and running down the bark, from rain flooding a collection
cup containing latex and from spillage from tapers buckets during collection.
It contains soil and other contaminants and has variable rubber content,
depending on the amount of contaminants.
Earth scrap is collected by field workers two or three times a year
and may be cleaned in a scrap washer to recover the rubber
or sold to a contractor who cleans it and recovers the rubber.
It is of low quality.
Processing.
Latex coagulates in the cups, if kept for long, and must be collected before this happens.
The collected latex field latex is transferred into coagulation tanks for the preparation of dry rubber or transferred into airtight containers with seething for ammoniation.
Ammoniation preserves the latex in a colloidal state for long.
periods of time. Latex is generally processed into either latex concentrate for
manufacture of dipped goods or coagulated under controlled clean conditions using
formic acid. The coagulated latex can then be processed into the higher grade
technically specified block rubbers such as SVR 3L or SVR CV or used to produce ribbed
smoked sheet grids. Naturally coagulated rubber cup lump is used in the manufacture of TSR-10
and TSR-20 grade rubbers. Processing for these grades is a size reduction in cleaning process
to remove contamination and prepare the material for the final stage of drying. The dried material
is then bailed and palletized for storage and shipment. Vulcanized rubber. Natural rubber is often
vulcanized, a process by which the rubber is heated in sulfur, peroxide, or bisphenol are added
to improve resistance and elasticity and to prevent it from perishing. Carbon black is often
used as an additive to rubber to improve its strengths, especially in vehicle tires, which account
for about 70% of carbon black production.
Transportation.
Natural rubber latex is shipped from factories in Southeast Asia, South America,
and West and Central Africa to destinations around the world.
As the cost of natural rubber has risen significantly,
and rubber products are dense,
the shipping methods offering the lowest cost per unit weight are preferred.
Depending on destination, warehouse availability, and transportation conditions, some methods are preferred by certain buyers.
In international trade, latex rubber is mostly shipped in 20-foot ocean containers.
Inside the container, smaller containers are used to store the latex.
Rubber shortage
Due to various causes such as plant disease, climate change, falling commodity
price of rubber, there is growing concern for the future supply of rubber.
Uses. Uncured rubber is used for cements.
For adhesive, insulation, and friction tapes, and for creep rubber used in insulating blankets and
footwear. Vulcanized rubber has many more applications. Resistance to abrasion makes
softer kinds of rubber valuable for the threads of vehicle tires.
and conveyor belts, and makes hard rubber valuable for pump housings and piping used in the handling
of abrasive sludge. The flexibility of rubber is appealing in hoses, tires, and rollers for devices
ranging from domestic clothes ringers to printing presses. Its elasticity makes it suitable for
various kinds of shock absorbers and for specialized machinery mountings designed to reduce
vibration. Its relative gas and permeability makes it useful in the manufacture of articles such as
air hoses, balloons, balls, and cushions. The resistance of rubber to water and to the action of most
fluid chemicals has led to its use in rainwear, diving gear, and chemical and medicinal tubing,
and as a lining for storage tanks, processing equipment, and railroad.
tank cars. Because of their electrical resistance, soft rubber goods are used as insulation and for
protective gloves, shoes, and blankets. Hard rubber is used for articles such as telephone
housings and parts for radio sets, meters, and other electrical instruments. The coefficient of
friction of rubber, which is high on dry surfaces and low on wet surfaces, leads to its
use for power transmission belting, highly flexible couplings, and for water lubricated bearings
in deep well pumps. Indian rubber balls or lacrosse balls are made of rubber. Around 25 million
tons of rubber are produced each year, in which 30% is natural. The remainder is synthetic
rubber derived from petrochemical sources. The top end of latex production results in latex products
such as surgeons, gloves, balloons, and other relatively high-value products.
The mid-range, which comes from the technically specified natural rubber materials,
ends up largely in tires, but also in conveyor belts, marine products, windshield wipers,
and miscellaneous goods. Natural rubber offers good elasticity,
while synthetic materials tend to offer better resistance to environmental factors,
such as oils, temperature, chemicals, and ultraviolet light.
Cured rubber is rubber that has been compounded and subjected to the vulcanization process
to create cross-links within the rubber matrix.
Allergic reactions
Some people have a serious latex allergy,
and exposure to natural latex rubber products such as latex gloves can cause anaphylactic shock.
The antigenic proteins found in Hevea latex may be deliberately reduced, though not eliminated, through processing.
Latex from non-Hevea sources such as Guayul can be used without allergic reaction by persons with an allergy to Hevea latex.
Some allergic reactions are not to the latex itself, but from residues of chemicals used to accelerate the cross-linking process.
Although this may be confused with an allergy to latex, it is distinct from it,
typically taking the form of type 4 hypersensitivity in the presence of traces of specific processing chemicals.
Microbial degradation
Natural rubber is susceptible to degradation by a wide range of bacteria.
The bacteria Streptomyces Coelicolor, pseudomonas, citronella,
and nocardia are capable of degrading vulcanized natural rubber.
