Latex is the stable dispersion (emulsion

Emulsion

An emulsion is a mixture of two or more liquids that are normally immiscible . Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion is used when both the dispersed and the...

) of polymer

Polymer

A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...

 microparticles in an aqueous medium. Latexes may be natural or synthetic.

Latex as found in nature is a milky fluid found in 10% of all flowering plants (angiosperms). It is a complex emulsion consisting of protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

s, alkaloid

Alkaloid

Alkaloids are a group of naturally occurring chemical compounds that contain mostly basic nitrogen atoms. This group also includes some related compounds with neutral and even weakly acidic properties. Also some synthetic compounds of similar structure are attributed to alkaloids...

s, starch

Starch

Starch or amylum is a carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds. This polysaccharide is produced by all green plants as an energy store...

es, sugar

Sugar

Sugar is a class of edible crystalline carbohydrates, mainly sucrose, lactose, and fructose, characterized by a sweet flavor.Sucrose in its refined form primarily comes from sugar cane and sugar beet...

s, oils, tannin

Tannin

A tannin is an astringent, bitter plant polyphenolic compound that binds to and precipitates proteins and various other organic compounds including amino acids and alkaloids.The term tannin refers to the use of...

s, resin

Resin

Resin in the most specific use of the term is a hydrocarbon secretion of many plants, particularly coniferous trees. Resins are valued for their chemical properties and associated uses, such as the production of varnishes, adhesives, and food glazing agents; as an important source of raw materials...

s, and gum

Natural gum

Natural gums are polysaccharides of natural origin, capable of causing a large viscosity increase in solution, even at small concentrations. In the food industry they are used as thickening agents, gelling agents, emulsifying agents, and stabilizers...

s that coagulates on exposure to air. It is usually exuded after tissue injury. In most plants, latex is white, but some have yellow, orange, or scarlet latex. Since the 17th century, latex has been used as a term for the fluid substance in plants. It serves mainly as defense against herbivorous insect

Insect

Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s. Many people are allergic to latex

Latex allergy

Latex allergy is a medical term encompassing a range of allergic reactions to natural rubber latex.-Type I:The most serious and rare form, type I is an immediate and potentially life-threatening reaction, not unlike the severe reaction some people have to bee stings...

.

The word is also used to refer to natural latex rubber

Rubber

Natural rubber, also called India rubber or caoutchouc, is an elastomer that was originally derived from latex, a milky colloid produced by some plants. The plants would be ‘tapped’, that is, an incision made into the bark of the tree and the sticky, milk colored latex sap collected and refined...

; particularly for non-vulcanized

Vulcanization

Vulcanization or vulcanisation is a chemical process for converting rubber or related polymers into more durable materials via the addition of sulfur or other equivalent "curatives." These additives modify the polymer by forming crosslinks between individual polymer chains. Vulcanized material is...

 rubber. Such is the case in products like latex glove

Glove

A glove is a garment covering the hand. Gloves have separate sheaths or openings for each finger and the thumb; if there is an opening but no covering sheath for each finger they are called "fingerless gloves". Fingerless gloves with one large opening rather than individual openings for each...

s, latex condom

Condom

A condom is a barrier device most commonly used during sexual intercourse to reduce the probability of pregnancy and spreading sexually transmitted diseases . It is put on a man's erect penis and physically blocks ejaculated semen from entering the body of a sexual partner...

s and latex clothing

Latex clothing

Latex rubber is used in many types of clothing. Rubber has traditionally been used in protective clothing, including gas masks and Wellington boots. Rubber is now generally being replaced in these application by plastics...

.

It can also be made synthetically

Chemical synthesis

In chemistry, chemical synthesis is purposeful execution of chemical reactions to get a product, or several products. This happens by physical and chemical manipulations usually involving one or more reactions...

 by polymerizing

Polymerization

In polymer chemistry, polymerization is a process of reacting monomer molecules together in a chemical reaction to form three-dimensional networks or polymer chains...

 a monomer

Monomer

A monomer is an atom or a small molecule that may bind chemically to other monomers to form a polymer; the term "monomeric protein" may also be used to describe one of the proteins making up a multiprotein complex...

 such as styrene that has been emulsified

Emulsion

An emulsion is a mixture of two or more liquids that are normally immiscible . Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion is used when both the dispersed and the...

 with surfactant

Surfactant

Surfactants are compounds that lower the surface tension of a liquid, the interfacial tension between two liquids, or that between a liquid and a solid...

s.

Articulated Laticifers

The cells

Cell (biology)

The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

 (laticifer

Laticifer

A laticifer is a type of elongated secretory cell found in the leaves and/or stems of plants that produce latex and rubber as secondary metabolites. Laticifers may be articulated, i.e., composed of a series of cells joined together, or non-articulated, consisting of one long cell...

s) in which latex is found make up the laticiferous system, which can form in two very different ways. In many plants, the laticiferous system is formed from rows of cells laid down in the meristem

Meristem

A meristem is the tissue in most plants consisting of undifferentiated cells , found in zones of the plant where growth can take place....

 of the stem

Plant stem

A stem is one of two main structural axes of a vascular plant. The stem is normally divided into nodes and internodes, the nodes hold buds which grow into one or more leaves, inflorescence , conifer cones, roots, other stems etc. The internodes distance one node from another...

 or root

Root

In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...

. The cell wall

Cell wall

The cell wall is the tough, usually flexible but sometimes fairly rigid layer that surrounds some types of cells. It is located outside the cell membrane and provides these cells with structural support and protection, and also acts as a filtering mechanism. A major function of the cell wall is to...

s between these cells are dissolved so that continuous tubes, called latex vessels, are formed. Since these vessels are made of many cells, they are known as articulated laticifers. This method of formation is found in the poppy family, in the rubber

Rubber

Natural rubber, also called India rubber or caoutchouc, is an elastomer that was originally derived from latex, a milky colloid produced by some plants. The plants would be ‘tapped’, that is, an incision made into the bark of the tree and the sticky, milk colored latex sap collected and refined...

 trees (Para rubber tree and Castilla elastica

Castilla elastica

Castilla elastica, the Panama Rubber Tree, is a tree native to the tropical areas of Mexico, Central America, and northern South America. It was the principal source of latex among the Mesoamerican peoples in pre-Columbian times...

), and in the Cichorieae

Cichorieae

Cichorieae is a tribe of plants in the family Asteraceae that includes 100 genera and more than 1,600 species. They are found primarily in temperate regions of the Eastern Hemisphere....

, a clade

Clade

A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

 in the Family Asteraceae

Asteraceae

The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...

 distinguished by the presence of latex in its members. It is also present in another member of the Asteraceae, the guayule

Guayule

Parthenium argentatum, commonly known as the Guayule , is a flowering shrub in the aster family, Asteraceae, that is native to the southwestern United States and northern Mexico. It can be found in the US states of New Mexico and Texas and the Mexican states of Zacatecas, Coahuila, Chihuahua, San...

 plant.

Non-articulated Laticifers

In the milkweed

Asclepias

Asclepias L. , the milkweeds, is a genus of herbaceous perennial, dicotyledonous plants that contains over 140 known species...

 and spurge

Euphorbiaceae

Euphorbiaceae, the Spurge family are a large family of flowering plants with 300 genera and around 7,500 species. Most are herbs, but some, especially in the tropics, are also shrubs or trees. Some are succulent and resemble cacti....

 families, on the other hand, the laticiferous system is formed quite differently. Early in the development of the seedling latex cells differentiate, and as the plant grows these latex cells grow into a branching system extending throughout the plant. In many euphorbs

Euphorbiaceae

Euphorbiaceae, the Spurge family are a large family of flowering plants with 300 genera and around 7,500 species. Most are herbs, but some, especially in the tropics, are also shrubs or trees. Some are succulent and resemble cacti....

, the entire structure is made from a single cell - this type of system is known as a non-articulated laticifer, to distinguish it from the multi-cellular structures discussed above. In the mature plant, the entire laticiferous system is descended from a single cell or group of cells present in the embryo

Embryo

An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...

.

The laticiferous system is present in all parts of the mature plant, including roots, stems, leaves

Leaf

A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....

, and sometimes the fruit

Fruit

In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...

s. It is particularly noticeable in the cortical

Cortex (botany)

In botany, the cortex is the outer layer of the stem or root of a plant, bounded on the outside by the epidermis and on the inside by the endodermis. It is composed mostly of undifferentiated cells, usually large thin-walled parenchyma cells of the ground tissue system. The outer cortical cells...

 tissues. Latex is usually exuded as a white liquid, but is some cases it can be clear, yellow, or red, as in Cannabaceae

Cannabaceae

Cannabaceae are a small family of flowering plants. As now circumscribed, the family includes about 170 species grouped in about 11 genera, including Cannabis , Humulus and Celtis...

.

Productive species

Latex is produced by 20,000 species from over 40 families occurring in multiple lineages in both dicotyledonous and monocotyledonous of plant. It is also found in conifers and pteridophyte

Pteridophyte

The pteridophytes are vascular plants that produce neither flowers nor seeds, and are hence called vascular cryptogams. Instead, they reproduce and disperse only via spores. Pteridophytes include horsetails, ferns, club mosses, and quillworts...

s. Several members of the fungal kingdom also produce latex upon injury, such as Lactarius deliciosus

Lactarius deliciosus

Lactarius deliciosus, commonly known as the Saffron milk cap, Red pine mushroom, is one of the best known members of the large milk-cap genus Lactarius in the order Russulales...

and other milk-caps

Lactarius

Lactarius is a genus of mushroom-producing fungi. The genus, collectively known commonly as milk-caps, are characterized by the fact that they exude a milky fluid if cut or damaged...

. This suggests it is the product of convergent evolution

Convergent evolution

Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...

 and has been selected for on many separate occasions.

14% of tropical plant species create latex, as opposed to 6% of temperate plant species.

Defense function

Latex functions to protect the plant from herbivores. The idea was first proposed in 1887 by Joseph F. James who noted that latex

“. . . carries with it at the same time such disagreeable properties that it becomes a better protection to the plant from enemies than all the thorns, prickles, or hairs that could be provided. In this plant, so copious and so distasteful has the sap become that it serves a most important purpose in its economy.”

Evidence showing this defense function include the finding that slugs will eat leaves drained of their latex but not intact ones, that many insects sever the veins carrying latex before they feed, and that the latex of Asclepias humistrata (sandhill milkweed) kills by trapping 30% of newly hatched monarch butterfly

Monarch butterfly

The Monarch butterfly is a milkweed butterfly , in the family Nymphalidae. It is perhaps the best known of all North American butterflies. Since the 19th century, it has been found in New Zealand, and in Australia since 1871 where it is called the Wanderer...

 caterpillars.

Other evidence is that latex contains 50–1000 higher concentrations of defense substances than other plant tissues. These toxins include ones that are also toxic to the plant and consist of a diverse range of chemicals that are either poisonous or "antinutritive". Latex is actively moved to the area of injury; in the case of Cryptostegia grandiflora, this can be more than 70 cm.

The clotting property of latex is functional in this defense since it limits wastage and its stickiness traps insects and their mouthparts.

It has been noted that while there exist other explanations for the existence of latex including storage and movement of plant nutrients, waste, and maintenance of water balance that "Essentially none of these functions remain credible and none have any empirical support."

Synthetic latices

Examples of synthetic latices are Styrene-butadiene

Styrene-butadiene

Styrene-Butadiene or Styrene-Butadiene-Rubber is a synthetic rubber copolymer consisting of styrene and butadiene. It has good abrasion resistance and good aging stability when protected by additives, and is widely used in car tires, where it may be blended with natural rubber...

 Rubber, Acrylonitrile butadiene styrene

Acrylonitrile butadiene styrene

Acrylonitrile butadiene styrene is a common thermoplastic. Its melting point is approximately 105 °C ....

, acrylic polymers, polyvinyl acetate

Polyvinyl acetate

Polyvinyl acetate, PVA, PVAc, poly, is a rubbery synthetic polymer with the formula n. It belongs to the polyvinyl esters family with the general formula -[RCOOCHCH2]-...

.

Uses of latex

The latex of many species can be processed to produce many materials.

Natural rubber

Rubber

Natural rubber, also called India rubber or caoutchouc, is an elastomer that was originally derived from latex, a milky colloid produced by some plants. The plants would be ‘tapped’, that is, an incision made into the bark of the tree and the sticky, milk colored latex sap collected and refined...

 is the most important product obtained from latex; more than 12,000 plant species yield latex containing rubber, though in the vast majority of those species the rubber is not suitable for commercial use. This latex is used to make many other products as well, including mattresses, gloves, swim cap

Swim cap

A swim cap, swimming cap or bathing cap, is a silicone, latex or lycra cap worn on the head by recreational and competitive swimmers....

s, condom

Condom

A condom is a barrier device most commonly used during sexual intercourse to reduce the probability of pregnancy and spreading sexually transmitted diseases . It is put on a man's erect penis and physically blocks ejaculated semen from entering the body of a sexual partner...

s, catheters and balloon

Balloon

A balloon is an inflatable flexible bag filled with a gas, such as helium, hydrogen, nitrous oxide, oxygen, or air. Modern balloons can be made from materials such as rubber, latex, polychloroprene, or a nylon fabric, while some early balloons were made of dried animal bladders, such as the pig...

s.

Balatá

Balatá

Manilkara bidentata is a species of Manilkara native to a large area of northern South America, Central America and the Caribbean. Common names include balatá, ausubo, massaranduba, and "cow-tree"....

 and gutta percha latex contain an inelastic polymer related to rubber.

Latex from the chicle

Chicle

Manilkara chicle is a tropical evergreen tree native to Mexico and Central America. The tree ranges from Veracruz in Mexico south to Atlántico in Colombia...

 and jelutong trees is used in chewing gum

Chewing gum

Chewing gum is a type of gum traditionally made of chicle, a natural latex product, or synthetic rubber known as polyisobutylene. For economical and quality reasons, many modern chewing gums use rubber instead of chicle...

.

Dried latex from the opium poppy

Opium poppy

Opium poppy, Papaver somniferum, is the species of plant from which opium and poppy seeds are extracted. Opium is the source of many opiates, including morphine , thebaine, codeine, papaverine, and noscapine...

 is opium

Opium

Opium is the dried latex obtained from the opium poppy . Opium contains up to 12% morphine, an alkaloid, which is frequently processed chemically to produce heroin for the illegal drug trade. The latex also includes codeine and non-narcotic alkaloids such as papaverine, thebaine and noscapine...

, the source of many useful opiate

Opiate

In medicine, the term opiate describes any of the narcotic opioid alkaloids found as natural products in the opium poppy plant.-Overview:Opiates are so named because they are constituents or derivatives of constituents found in opium, which is processed from the latex sap of the opium poppy,...

s and other alkaloid

Alkaloid

Alkaloids are a group of naturally occurring chemical compounds that contain mostly basic nitrogen atoms. This group also includes some related compounds with neutral and even weakly acidic properties. Also some synthetic compounds of similar structure are attributed to alkaloids...

s of high value.

Synthetic latexes are used in coating

Coating

Coating is a covering that is applied to the surface of an object, usually referred to as the substrate. In many cases coatings are applied to improve surface properties of the substrate, such as appearance, adhesion, wetability, corrosion resistance, wear resistance, and scratch resistance...

s (e.g. latex paint) and glue

Glue

This is a list of various types of glue. Historically, the term "glue" only referred to protein colloids prepared from animal flesh. The meaning has been extended to refer to any fluid adhesive....

s because they solidify by coalescence of the polymer particles as the water evaporates, and therefore can form films without releasing potentially toxic organic solvents in the environment. Other uses include cement additives. Latex, usually styrene based, is also used in immunoassays.

Latex clothing

Latex is used in many types of clothing

Clothing

Clothing refers to any covering for the human body that is worn. The wearing of clothing is exclusively a human characteristic and is a feature of nearly all human societies...

. Worn on the body (or applied directly by painting) it tends to be skin-tight, producing a "second skin" effect.

Latex mattress

When latex is derived from the hevea brasiliensis tree, it has the consistency of maple syrup. There are two primary processes used to transform it to the latex foam used in mattresses: the Talalay process

Talalay Process

The Talalay process is a method of producing molded pieces of natural latex foam rubber. A natural liquid latex rubber base is introduced to a closed mold that has been vacuumed of air. The mold is then frozen to stabilize the cell structure. Carbon dioxide gas is introduced and the mold is...

 and the Dunlop

Dunlop Rubber

Dunlop Rubber was a company based in the United Kingdom which manufactured tyres and other rubber products for most of the 20th century. It was acquired by BTR plc in 1985. Since then, ownership of the Dunlop trade-names has been fragmented.-Early history:...

 process. The Dunlop process produces a latex foam that is more dense, while the Talalay process produces a latex foam that is lighter and has more air in it. Using a cake as an analogy, Dunlop would be like pound cake and Talalay would be like angel food cake. If you were to weigh each as latex cores, the Dunlop would be heavier because it has more latex in it.

Allergic reactions

Some people have a serious latex allergy

Latex allergy

Latex allergy is a medical term encompassing a range of allergic reactions to natural rubber latex.-Type I:The most serious and rare form, type I is an immediate and potentially life-threatening reaction, not unlike the severe reaction some people have to bee stings...

, and exposure to latex products such as latex gloves can cause anaphylactic shock. Guayule

Guayule

Parthenium argentatum, commonly known as the Guayule , is a flowering shrub in the aster family, Asteraceae, that is native to the southwestern United States and northern Mexico. It can be found in the US states of New Mexico and Texas and the Mexican states of Zacatecas, Coahuila, Chihuahua, San...

 latex is hypoallergenic

Hypoallergenic

Hypoallergenic, meaning "below normal" or "slightly" allergenic, was a term first used in a cosmetics campaign in 1953. It is used to describe items that cause or are claimed to cause fewer allergic reactions...

 and is being researched as a substitute to the allergy-inducing Hevea

Hevea

Hevea is a genus of flowering plants in the spurge family, Euphorbiaceae. It is also one of many names used commercially for the wood of the most economically important species H. brasiliensis.-Selected species:* Hevea benthamiana Müll.Arg....

 latexes. Additionally, chemical processes may be employed to reduce the amount of antigenic protein in Hevea latex, yielding alternative materials such as Vytex Natural Rubber Latex

Vytex Natural Rubber Latex

Vytex Natural Rubber Latex is a brand of natural rubber latex produced and marketed by Vystar Corporation. Vytex NRL is an alternative material to petroleum-based synthetics and traditional, or Hevea, natural rubber latex...

 which provide significantly reduced exposure to latex allergens.

Many people with spina bifida

Spina bifida

Spina bifida is a developmental congenital disorder caused by the incomplete closing of the embryonic neural tube. Some vertebrae overlying the spinal cord are not fully formed and remain unfused and open. If the opening is large enough, this allows a portion of the spinal cord to protrude through...

are also allergic to natural latex rubber, as well as people who have had multiple surgeries, and people who have had prolonged exposure to natural latex.