Word Finder - latex

definition

A clear liquid believed to be a component of a humour or other bodily fluid (esp. plasma and lymph)

definition

The milky sap of several trees that coagulates on exposure to air; used to make rubber.

definition

An emulsion of rubber in water, used in adhesives and the like.

definition

Natural latex rubber, especially non-vulcanized rubber, such as is used in making latex gloves, latex condoms, and latex clothing.

The trees are regularly tapped and the coagulated latex which exudes is collected and worked up into rubber.

To obtain the rubber, the latex is usually treated in the following manner.

As the removal of the impurities of the latex is one of the essential points to be aimed at, it was thought that the use of a centrifugal machine to separate the caoutchouc as a cream from the watery part of the latex would prove to be a satisfactory process.

The watery portion of the latex soaks into the trunk, and the soft spongy rubber which remains is kneaded and pressed into lumps or balls.

There is no feasible method at present known of preventing the inclusion of the resin of the latex with the rubber during coagulation, and although the separation of the resin from the solid caoutchouc by means of solvents is possible, it is not practicable or profitable commercially.

In Nicaragua the latex is collected in April, when the old leaves begin to fall and the new ones are appearing, during which time the latex is richest.

The latex flows fairly well, but is usually allowed to dry on the tree.

As a secondary function we may recognize, in certain cases, the power of closing wounds, which results from the rapid coagulation of exuded latex in contact with the air.

Laticiferous Tissue.The laticiferous tissue consists of a network of branching or anastomosing tubes which contain a coagulable fluid known as latex.

The rows of cells from which the laticiferous vessels are formed can be distinguished in many cases in the young embryo while still in the dry seed (Scott), but the latex vessels in process of formation are more easily seen when germination has begun.

The effect of chemical agents in producing coagulation are in consonance with what is known of other instances of polymeric or condensation changes, whilst the fact that the collection of globules separated by creaming after thorough washing, and therefore removal of all proteid, is susceptible of solidification into caoutchouc by a merely mechanical act such as churning, strongly supports the view that the character of the change is distinct from that of any alteration which may occur in the proteid constituents of the latex.

The latex is therefore usually allowed to coagulate on the tree, as it slowly exudes from the incision.

The rubber is usually dark in colour and is often contaminated with proteid impurities derived from the latex.

The latex, which is usually coagulated by standing or by heating, is obtained from incisions in the bark of the tree.

Besides the trees described above, a number of climbing plants or vines belonging to the Apocyanaceae secrete a latex which furnishes rubber of good quality.

The rubber is obtained by incising the stems of the vines and coagulating the latex by exposure, by admixture with acid vegetable juices or by heating.

Little is at present known of the large rubber tree of Tonkin (Bleckrodea tonkinensis), the latex of which is stated to furnish excellent rubber.

The latex is collected in the so-called dry season between June and February.

The trees are tapped in the early morning when the latex is most readily obtained.

To obtain the latex, deep incisions are made near the base of the tree extending up the trunk.

The latex usually furnished about 30% of rubber.

The seedlings rapidly developed and in most places in which they were planted grew into large trees which furnished satisfactory latex when tapped in their sixth or seventh year.

Africa the Hevea which has been planted promises well, especially in the Gold Coast, where good yields of latex are stated to have been obtained.

One of the most important subjects in connexion with rubber plantations is the method to be adopted in tapping the trees for latex.

At present it cannot be said that finality has been reached on the subject of the best method, giving a good return of latex with a minimum of damage to the tree.

The yield of latex is at first small, but increases with successive tappings, which appear to stimulate the local production of latex, and finally reaches a maximum.

Too frequent tapping leads to the production of latex poor in caoutchouc, whilst tapping of trees before they are six or seven years old, and from 20-25 in.

The point of next importance is the coagulation of the latex so as to produce rubber in the form and of the quality required by the manufacturer.

This method is said to answer well with the latex of Castilloa, but it appears to be inapplicable to the latex of Hevea, which does not cream readily when centrifugalized.

The plan usually adopted is to collect the latex in rectangular tanks or casks.

After brushing away the loose stones and dirt from the root of the tree by means of a handful of twigs, the collector lays down large leaves for the latex to drop upon.

The latex, which exudes slowly and in many tortuous courses, some of it ultimately falling on the ground, is allowed to remain on the tree for several days, until it becomes dry and solid, when it is pulled off in strings, which are either rolled up into balls or put into bags in loose masses, in which form it enters commerce under the name of Ceara " scrap."

The latex coagulates readily, especially if churned or if diluted with water, when a purer rubber is obtained.

Since the latex " creams " readily the rubber can be separated from the latex by centrifugalizing, and its quality and market value thus enhanced.

The Funtumia latex can also be coagulated by the astringent infusion of Bauhinia leaves or by exposing it in shallow dishes, when the liquid " creams."

The cups when full are poured into a larger vessel, and solution of alum is added to coagulate the latex.

Rubber is chiefly composed of the soft, solid, elastic substance known as caoutchouc. It is usually assumed that this substance is present as such in the latex.

The globules in the latex, however, consist more probably of a distinct liquid substance which readily changes into the solid caoutchouc. The coagulation of the latex often originates with the " curding " of the proteids present, and this alteration in the proteid leads to the solidification of the globules into caoutchouc. The latter, however, is probably a distinct effect.

Under certain conditions, as when latex is allowed to stand or is centrifugalized, a cream is obtained consisting of the liquid globules, which may be washed free from proteid without change, but, either by mechanical agitation or by the addition of acid or other chemical agent, the liquid gradually solidifies to a mass of solid caoutchouc. The phenomenon therefore resembles the change known to the chemist as polymerization, by which through molecular aggregation a liquid may pass into a solid without change in its empirical composition.

So far the chemical nature of the liquid globules of the latex is unknown, and the exact character of the change into solid caoutchouc remains to be determined.

The watery liquid known as rubber milk or latex is an emulsion consisting chiefly of a weak watery solution of proteids, carbohydrates and salts holding the liquid globules in suspension.

The dissolved salts (potassium, sodium, ammonium, calcium, magnesium, &c.) of the latex are generally nearly entirely absent from the wellprepared rubber.

The presence of more than a small percentage of resin in the latex leads to the production of rubber containing much resin, which seriously depreciates its commercial value for most purposes.

Several members of the order are used medicinally for the strong purging properties of the milky juice (latex) which they contain; scammony is the dried latex from the underground stem of Convolvulus Scarnmonia, a native of the Levant, while jalap is the product of the tubercles of Exogonium Purga, a native of Mexico.

Latex the same sum was again granted, and there was still a good deal unexpended when the larger measure of 1891 became law.

The Baarnsche Bosch, or wood, stretches southward to Soestdyk, where there is a royal country Roman Byzantine Early Christian Work Fr = Latex Work seat, originally acquired by the state in 1795 Louis Bonaparte, king of Holland, who was very fond of the spot, formed a zoological collection here which was removed to Amsterdam in 1809.

Field trials of this latex agglutination test are now required.

High risk patients should be offered clinical testing for latex allergy.

Bitter aloes are made from the dried, purified sap obtained from the latex - the thin layer of tissue directly beneath the skin.

These are words preceded by a backslash (like in LaTeX ).