Papaya Sap

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  • Topic: Rubber, Euphorbiaceae, Para rubber tree
  • Pages : 13 (2699 words )
  • Download(s) : 1271
  • Published : November 24, 2010
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Chapter I

Rubber is an elastic hydrocarbon polymer which occurs as a milky emulsion (known as latex) in the sap of a number of plants but can also be produced synthetically. The major commercial source of the latex used to create rubber is the Para rubber tree, Hevea brasiliensis (Euphorbiaceae). This is largely because it responds to wounding by producing more latex. Other plants containing latex include figs, euphorbias and the common dandelion. These have not been a major source of rubber, though when Germany was cut off from supplies of rubber during World War II, attempts were made to use such sources, before being supplanted by the development of synthetic rubber. It is believed to have been named by Joseph Priestley, who discovered in 1770 that dried latex rubbed out pencil marks. In its native Central America and South America, rubber has been collected for a long time. The Mesoamerican civilizations used rubber mostly from Castilla elastica. The Ancient Mesoamericans had a ball game using rubber balls (see: Mesoamerican ballgame), and a few Pre-Columbian rubber balls have been found (always in sites that were flooded under fresh water), the earliest dating to about 1600 BC. According to Bernal Díaz del Castillo, the Spanish Conquistadores were so astounded by the vigorous bouncing of the rubber balls of the Aztecs that they wondered if the balls were enchanted by evil spirits. The Maya also made a type of temporary rubber shoe by dipping their feet into a latex mixture. Rubber was used in various other contexts, such as strips to hold stone and metal tools to wooden handles, and padding for the tool handles. While the ancient Mesoamericans did not have vulcanization, they developed organic methods of processing the rubber with similar results, mixing the raw latex with various saps and juices of other vines, particularly Ipomoea alba, a species of Morning glory. In Brazil the natives understood the use of rubber to make water-resistant cloth. A story says that the first European to return to Portugal from Brazil with samples of such water-repellent rubberized cloth so shocked people that he was brought to court on the charge of witchcraft. When samples of rubber first arrived in England, it was observed that a piece of the material was extremely good for rubbing out pencil marks on paper. This was the origin of the material's English name of 'rubber'. Blocks of the material are still used for this purpose, and known as 'rubbers' in England, causing occasional amusement to Americans, to whom a 'rubber' is a condom. The sap is any liquid found in the stems of plants, including the liquid material that moves the younger annual rings and bark of trees and watery juices of herbaceous plants. Natural rubber is another valuable sap. The papaya’s milky sap is also called latex. Latex is a milky fluid produced by rubber trees. Latex is also used to make rubber Since papaya fruits produce latex like rubber plants, the study “Rubber Material Source from Papaya (Carica papaya) Milky Sap” was formulated. The study aimed to use papaya sap as main ingredient in making bioplastic because it contains starch which is one of the components in making bioplastic and also, the sap or latex is used in making rubber. Papaya is found anywhere so there is adequate supply of the main ingredient. Plus, the flow of the papaya sap is continuousand it is environment friendly because it doesn’t harm the plant. The study is to be conducted to produce bioplastic so that the plastics that people are using in the present could somehow be replaced with the use of this investigatory project to lessen the environmental effects of the decomposition of plastics. Objectives of the Study

This investigation is anchored on the following objectives: 1) To evaluate and compare the, the appearance, texture, elasticity...
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