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59-521: The tapping of the gum is similar to the tapping of latex from the rubber tree: zig-zag gashes are made in the tree trunk and the dripping gum is collected in small bags. It is then boiled until it reaches the correct thickness. Locals who collect chicle are called chicleros . The word chicle comes from the Nahuatl word for the gum, tzictli [ˈt͡sikt͡ɬi] , which can be translated as "sticky stuff". Alternatively, it may have come from

118-424: A "second skin" effect. Synthetic latices are used in coatings (e.g., latex paint) and glues because they solidify by coalescence of the polymer particles as the water evaporates. These synthetic latices therefore can form films without releasing potentially toxic organic solvents in the environment. Other uses include cement additives and to conceal information on scratchcards . Latex, usually styrene -based,

177-439: 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

236-406: A branching system extending throughout the plant. In many euphorbs , 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 . The laticiferous system

295-432: A colloid such as milk, the colloidal particles are globules of fat, rather than individual fat molecules. Because colloid is multiple phases, it has very different properties compared to fully mixed, continuous solution. The following forces play an important role in the interaction of colloid particles: The Earth’s gravitational field acts upon colloidal particles. Therefore, if the colloidal particles are denser than

354-478: A colloid. The scattered light will form an interference pattern, and the fluctuation in light intensity in this pattern is caused by the Brownian motion of the particles. If the apparent size of the particles increases due to them clumping together via aggregation, it will result in slower Brownian motion. This technique can confirm that aggregation has occurred if the apparent particle size is determined to be beyond

413-405: A latex allergy. Latex-fruit syndrome Many people with latex allergy also experience allergic reactions to certain fruits. This association has led to research regarding latex-fruit syndrome (LFS). This is a phenomenon characterized by cross-reactivity between natural latex rubber allergens and certain fruit allergens, leading to allergic reactions in sensitized individuals. It was described for

472-531: A lower-allergen substitute. 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 which provide significantly reduced exposure to latex allergens. About half of people with spina bifida are also allergic to natural latex rubber. People who have had multiple surgeries and who have had prolonged exposure to natural latex are also more susceptible to

531-462: A natural diffraction grating for visible light waves , particularly when the interstitial spacing is of the same order of magnitude as the incident lightwave. Thus, it has been known for many years that, due to repulsive Coulombic interactions, electrically charged macromolecules in an aqueous environment can exhibit long-range crystal -like correlations with interparticle separation distances, often being considerably greater than

590-438: A perturbation. Aggregation causes sedimentation or creaming, therefore the colloid is unstable: if either of these processes occur the colloid will no longer be a suspension. Electrostatic stabilization and steric stabilization are the two main mechanisms for stabilization against aggregation. A combination of the two mechanisms is also possible (electrosteric stabilization). A method called gel network stabilization represents

649-500: A result of the relatively simple methods that have evolved in the last 20 years for preparing synthetic monodisperse colloids (both polymer and mineral) and, through various mechanisms, implementing and preserving their long-range order formation. Colloidal phase separation is an important organising principle for compartmentalisation of both the cytoplasm and nucleus of cells into biomolecular condensates —similar in importance to compartmentalisation via lipid bilayer membranes ,

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708-877: A type of liquid crystal . The term biomolecular condensate has been used to refer to clusters of macromolecules that arise via liquid-liquid or liquid-solid phase separation within cells. Macromolecular crowding strongly enhances colloidal phase separation and formation of biomolecular condensates . Colloidal particles can also serve as transport vector of diverse contaminants in the surface water (sea water, lakes, rivers, fresh water bodies) and in underground water circulating in fissured rocks (e.g. limestone , sandstone , granite ). Radionuclides and heavy metals easily sorb onto colloids suspended in water. Various types of colloids are recognised: inorganic colloids (e.g. clay particles, silicates, iron oxy-hydroxides ), organic colloids ( humic and fulvic substances). When heavy metals or radionuclides form their own pure colloids,

767-489: Is actively moved to the area of injury; in the case of Cryptostegia grandiflora , latex more than 70 cm from the site of injury is mobilized. The large hydrostatic pressure in this vine enables an extremely high flow rate of latex. In a 1935 report the botanist Catherine M. Bangham observed that "piercing the fruit stalk of Cryptostegia grandiflora produced a jet of latex over a meter long, and maintained [this jet] for several seconds." The clotting property of latex

826-416: Is also slow. Colloid A colloid is a mixture in which one substance consisting of microscopically dispersed insoluble particles is suspended throughout another substance. Some definitions specify that the particles must be dispersed in a liquid , while others extend the definition to include substances like aerosols and gels . The term colloidal suspension refers unambiguously to

885-469: Is also used in immunoassays . Some people only experience a mild allergy when exposed to latex, with symptoms such as eczema , contact dermatitis , or developing a rash . Others have a serious latex allergy , and exposure to latex products such as latex gloves can cause anaphylactic shock . Guayule latex has only 2% of the levels of protein found in Hevea latices, and it is being researched as

944-432: Is also used to refer to natural latex rubber , particularly non- vulcanized rubber. Such is the case in products like latex gloves , latex condoms , latex clothing , and balloons . Latex : Colloidal dispersion of polymer particles in a liquid. Synthetic latex : Latex obtained as a product of an emulsion , mini-emulsion, micro-emulsion, or dispersion polymerization . The cells ( laticifers ) in which latex

1003-434: Is an emulsion (stable dispersion) of polymer microparticles in water. Latices are found in nature , but synthetic latices are common as well. In nature, latex is found as a milky fluid , which is present in 10% of all flowering plants (angiosperms). It is a complex emulsion that coagulates on exposure to air, consisting of proteins , alkaloids , starches , sugars , oils , tannins , resins , and gums . It

1062-481: Is defined by particles remaining suspended in solution and depends on the interaction forces between the particles. These include electrostatic interactions and van der Waals forces , because they both contribute to the overall free energy of the system. A colloid is stable if the interaction energy due to attractive forces between the colloidal particles is less than kT , where k is the Boltzmann constant and T

1121-489: Is directly proportional to the average particle size and volume fraction of the dispersed phase. Therefore, local changes in concentration caused by sedimentation or creaming, and clumping together of particles caused by aggregation, are detected and monitored. These phenomena are associated with unstable colloids. Dynamic light scattering can be used to detect the size of a colloidal particle by measuring how fast they diffuse. This method involves directing laser light towards

1180-474: Is found in the poppy family and in the rubber trees ( Para rubber tree , members of the family Euphorbiaceae , members of the mulberry and fig family , such as the Panama rubber tree Castilla elastica ), and members of the family Asteraceae . For instance, Parthenium argentatum the guayule plant, is in the tribe Heliantheae ; other latex-bearing Asteraceae with articulated laticifers include members of

1239-430: 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 of the stem or root . The cell walls 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

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1298-455: Is functional in this defense since it limits wastage and its stickiness traps insects and their mouthparts. While there exist other explanations for the existence of latex including storage and movement of plant nutrients, waste, and maintenance of water balance that "[e]ssentially none of these functions remain credible and none have any empirical support". The latex of many species can be processed to produce many materials. Natural rubber

1357-595: Is present in all parts of the mature plant, including roots, stems, leaves , and sometimes the fruits . It is particularly noticeable in the cortical tissues. Latex is usually exuded as a white liquid, but is some cases it can be clear, yellow or red, as in Cannabaceae . Latex is produced by 20,000 flowering plant species from over 40 families . These include both dicots and monocots . Latex has been found in 14 percent of tropical plant species, as well as six percent of temperate plant species. Several members of

1416-648: Is the absolute temperature . If this is the case, then the colloidal particles will repel or only weakly attract each other, and the substance will remain a suspension. If the interaction energy is greater than kT, the attractive forces will prevail, and the colloidal particles will begin to clump together. This process is referred to generally as aggregation , but is also referred to as flocculation , coagulation or precipitation . While these terms are often used interchangeably, for some definitions they have slightly different meanings. For example, coagulation can be used to describe irreversible, permanent aggregation where

1475-477: Is the scattering of light by particles in the colloid. Other colloids may be opaque or have a slight color. Colloidal suspensions are the subject of interface and colloid science . This field of study began in 1845 by Francesco Selmi , who called them pseudosolutions, and expanded by Michael Faraday and Thomas Graham , who coined the term colloid in 1861. Colloid : Short synonym for colloidal system. Colloidal : State of subdivision such that

1534-496: 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 including mattresses , gloves , swim caps , condoms , catheters and balloons . Dried latex from the opium poppy is called opium , the source of several useful analgesic alkaloids such as codeine , thebaine , and morphine ,

1593-421: Is the sedimentation or creaming velocity. The mass of the colloidal particle is found using: where and ρ 1 − ρ 2 {\displaystyle \rho _{1}-\rho _{2}} is the difference in mass density between the colloidal particle and the suspension medium. By rearranging, the sedimentation or creaming velocity is: There is an upper size-limit for

1652-956: Is used to control colloid suspensions. A colloidal crystal is a highly ordered array of particles that can be formed over a very long range (typically on the order of a few millimeters to one centimeter) and that appear analogous to their atomic or molecular counterparts. One of the finest natural examples of this ordering phenomenon can be found in precious opal , in which brilliant regions of pure spectral color result from close-packed domains of amorphous colloidal spheres of silicon dioxide (or silica , SiO 2 ). These spherical particles precipitate in highly siliceous pools in Australia and elsewhere, and form these highly ordered arrays after years of sedimentation and compression under hydrostatic and gravitational forces. The periodic arrays of submicrometre spherical particles provide similar arrays of interstitial voids , which act as

1711-512: 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, deriving from the Latin word for "liquid". It serves mainly as defense against herbivorous insects . Latex is not to be confused with plant sap ; it is a distinct substance, separately produced, and with different functions. The word latex

1770-483: The Cichorieae , a clade whose members produce latex, some of them in commercially interesting amounts. This includes Taraxacum kok-saghyz , a species cultivated for latex production. In the milkweed and spurge 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

1829-773: The Mayan word tsicte . Chicle was well known to the Aztecs and to the Maya , and early European settlers prized it for its subtle flavor and high sugar content. The word is used in the Americas and Spain to refer to chewing gum, chicle being a common term for it in Spanish and chiclete being the Portuguese term (both in Brazil and in parts of Portugal; other areas also use

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1888-417: The case of non-ionic surfactants or more generally interactions forces inside the system. Storing a dispersion at high temperatures enables to simulate real life conditions for a product (e.g. tube of sunscreen cream in a car in the summer), but also to accelerate destabilisation processes up to 200 times. Mechanical acceleration including vibration, centrifugation and agitation are sometimes used. They subject

1947-446: The chemical conditions of the soil sample, i.e. soil pH . Colloid solutions used in intravenous therapy belong to a major group of volume expanders , and can be used for intravenous fluid replacement . Colloids preserve a high colloid osmotic pressure in the blood, and therefore, they should theoretically preferentially increase the intravascular volume , whereas other types of volume expanders called crystalloids also increase

2006-626: The control of rheology and the physical modification of form and texture. Some hydrocolloids like starch and casein are useful foods as well as rheology modifiers, others have limited nutritive value, usually providing a source of fiber. The term hydrocolloids also refers to a type of dressing designed to lock moisture in the skin and help the natural healing process of skin to reduce scarring, itching and soreness. Hydrocolloids contain some type of gel-forming agent, such as sodium carboxymethylcellulose (NaCMC) and gelatin. They are normally combined with some type of sealant, i.e. polyurethane to 'stick' to

2065-413: The diameter of colloidal particles because particles larger than 1 μm tend to sediment, and thus the substance would no longer be considered a colloidal suspension. The colloidal particles are said to be in sedimentation equilibrium if the rate of sedimentation is equal to the rate of movement from Brownian motion. There are two principal ways to prepare colloids: The stability of a colloidal system

2124-710: The first time by Blanco et al. in 1994. In a 2024 comprehensive review by Gromek et al., the last 30 years of research on LFS were summarized, focusing on its prevalence, common cross-reactions, and clinical manifestations. The review found that the prevalence of LFS in latex-allergic patients varies widely, ranging from 4% to 88%, depending on diagnostic methods, geographical regions, and study populations. The most commonly implicated fruits in LFS include banana, avocado, kiwifruit, and papaya. Clinical manifestations are predominantly systemic, with 73% of hypersensitivity symptoms being systemic and 27% localized. Gromek et al. also highlighted

2183-400: The forces holding the particles together are stronger than any external forces caused by stirring or mixing. Flocculation can be used to describe reversible aggregation involving weaker attractive forces, and the aggregate is usually called a floc . The term precipitation is normally reserved for describing a phase change from a colloid dispersion to a solid (precipitate) when it is subjected to

2242-513: The forces that govern the structure and behavior of matter, such as excluded volume interactions or electrostatic forces, govern the structure and behavior of colloidal suspensions. For example, the same techniques used to model ideal gases can be applied to model the behavior of a hard sphere colloidal suspension. Phase transitions in colloidal suspensions can be studied in real time using optical techniques, and are analogous to phase transitions in liquids. In many interesting cases optical fluidity

2301-447: The fungal kingdom also produce latex upon injury, such as Lactarius deliciosus and other milk-caps . This suggests it is the product of convergent evolution and has been selected for on many separate occasions. Latex functions to protect the plant from herbivores. The idea was first proposed in 1887 by Joseph F. James, who noted that latex of milkweed carries with it at the same time such disagreeable properties that it becomes

2360-444: The individual particle diameter. In all of these cases in nature, the same brilliant iridescence (or play of colors) can be attributed to the diffraction and constructive interference of visible lightwaves that satisfy Bragg’s law , in a matter analogous to the scattering of X-rays in crystalline solids. The large number of experiments exploring the physics and chemistry of these so-called "colloidal crystals" has emerged as

2419-411: The latex of Asclepias humistrata (sandhill milkweed ) kills by trapping 30% of newly hatched monarch butterfly 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

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2478-441: The latter two of which can then further be used in the synthesis and manufacture of other (typically stronger) opioids for medicinal use, and of heroin for the illegal drug trade . The opium poppy is also the source of medically useful non-analgesic alkaloids, such as papaverine and noscapine . Latex is used in many types of clothing . Worn on the body (or applied directly by painting), it tends to be skin-tight , producing

2537-486: The medium of suspension, they will sediment (fall to the bottom), or if they are less dense, they will cream (float to the top). Larger particles also have a greater tendency to sediment because they have smaller Brownian motion to counteract this movement. The sedimentation or creaming velocity is found by equating the Stokes drag force with the gravitational force : where and v {\displaystyle v}

2596-636: The molecules or polymolecular particles dispersed in a medium have at least one dimension between approximately 1 nm and 1 μm, or that in a system discontinuities are found at distances of that order. Colloids can be classified as follows: Homogeneous mixtures with a dispersed phase in this size range may be called colloidal aerosols , colloidal emulsions , colloidal suspensions , colloidal foams , colloidal dispersions , or hydrosols . Hydrocolloids describe certain chemicals (mostly polysaccharides and proteins ) that are colloidally dispersible in water . Thus becoming effectively "soluble" they change

2655-418: The need for standardized diagnostic criteria and severity grading systems to improve the accuracy of LFS diagnosis and treatment. Several species of the microbe genera Actinomycetes , Streptomyces , Nocardia , Micromonospora , and Actinoplanes are capable of consuming rubber latex. However, the rate of biodegradation is slow, and the growth of bacteria utilizing rubber as a sole carbon source

2714-464: The overall mixture (although a narrower sense of the word suspension is distinguished from colloids by larger particle size). A colloid has a dispersed phase (the suspended particles) and a continuous phase (the medium of suspension). The dispersed phase particles have a diameter of approximately 1 nanometre to 1 micrometre . Some colloids are translucent because of the Tyndall effect , which

2773-673: The principal way to produce colloids stable to both aggregation and sedimentation. The method consists in adding to the colloidal suspension a polymer able to form a gel network. Particle settling is hindered by the stiffness of the polymeric matrix where particles are trapped, and the long polymeric chains can provide a steric or electrosteric stabilization to dispersed particles. Examples of such substances are xanthan and guar gum . Destabilization can be accomplished by different methods: Unstable colloidal suspensions of low-volume fraction form clustered liquid suspensions, wherein individual clusters of particles sediment if they are more dense than

2832-416: The process of ultrafiltration occurring in dense clay membrane. The question is less clear for small organic colloids often mixed in porewater with truly dissolved organic molecules. In soil science , the colloidal fraction in soils consists of tiny clay and humus particles that are less than 1μm in diameter and carry either positive and/or negative electrostatic charges that vary depending on

2891-536: The product to different forces that pushes the particles / droplets against one another, hence helping in the film drainage. Some emulsions would never coalesce in normal gravity, while they do under artificial gravity. Segregation of different populations of particles have been highlighted when using centrifugation and vibration. In physics , colloids are an interesting model system for atoms . Micrometre-scale colloidal particles are large enough to be observed by optical techniques such as confocal microscopy . Many of

2950-527: The rheology of water by raising the viscosity and/or inducing gelation. They may provide other interactive effects with other chemicals, in some cases synergistic, in others antagonistic. Using these attributes hydrocolloids are very useful chemicals since in many areas of technology from foods through pharmaceuticals , personal care and industrial applications, they can provide stabilization, destabilization and separation, gelation, flow control, crystallization control and numerous other effects. Apart from uses of

3009-470: The skin. A colloid has a dispersed phase and a continuous phase, whereas in a solution , the solute and solvent constitute only one phase. A solute in a solution are individual molecules or ions , whereas colloidal particles are bigger. For example, in a solution of salt in water, the sodium chloride (NaCl) crystal dissolves, and the Na and Cl ions are surrounded by water molecules.  However, in

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3068-471: The soluble forms some of the hydrocolloids have additional useful functionality in a dry form if after solubilization they have the water removed - as in the formation of films for breath strips or sausage casings or indeed, wound dressing fibers, some being more compatible with skin than others. There are many different types of hydrocolloids each with differences in structure function and utility that generally are best suited to particular application areas in

3127-401: The suspension medium, or cream if they are less dense. However, colloidal suspensions of higher-volume fraction form colloidal gels with viscoelastic properties. Viscoelastic colloidal gels, such as bentonite and toothpaste , flow like liquids under shear, but maintain their shape when shear is removed. It is for this reason that toothpaste can be squeezed from a toothpaste tube, but stays on

3186-537: The term chicla ). The word has also been exported to other languages such as Greek , which refers to chewing gum as τσίχλα ( tsichla ). Both the Aztecs and Maya traditionally chewed chicle. It was chewed as a way to stave off hunger, freshen breath, and keep teeth clean. Chicle was also used by the Maya as a filling for tooth cavities . The American company American Chicle Company , incorporated in June 1899,

3245-480: The term " eigencolloid " is used to designate pure phases, i.e., pure Tc(OH) 4 , U(OH) 4 , or Am(OH) 3 . Colloids have been suspected for the long-range transport of plutonium on the Nevada Nuclear Test Site . They have been the subject of detailed studies for many years. However, the mobility of inorganic colloids is very low in compacted bentonites and in deep clay formations because of

3304-436: The toothbrush after it is applied. The most widely used technique to monitor the dispersion state of a product, and to identify and quantify destabilization phenomena, is multiple light scattering coupled with vertical scanning. This method, known as turbidimetry , is based on measuring the fraction of light that, after being sent through the sample, it backscattered by the colloidal particles. The backscattering intensity

3363-559: The typical size range for colloidal particles. The kinetic process of destabilisation can be rather long (up to several months or years for some products). Thus, it is often required for the formulator to use further accelerating methods to reach reasonable development time for new product design. Thermal methods are the most commonly used and consist of increasing temperature to accelerate destabilisation (below critical temperatures of phase inversion or chemical degradation). Temperature affects not only viscosity, but also interfacial tension in

3422-536: Was the first prominent commercial user of this ingredient in the production of chewing gum. Its brand name, Chiclets , is derived from the word chicle. In response to a land reform law passed in Guatemala in 1952 which ended feudal work relations and expropriated unused lands and sold them to the indigenous and peasants, the William Wrigley Company discontinued buying Guatemalan chicle. Since it

3481-403: Was the sole buyer of Guatemalan chicle, the government was forced to create a massive aid program for growers. By the 1960s, most chewing gum companies had switched from using chicle to butadiene -based synthetic rubber , which was cheaper to manufacture. Only a handful of small gum companies still use chicle, including Gud Gum, Glee Gum, Simply Gum, and Tree Hugger Gum. Latex Latex

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