History [edit] Plastic as invention is attributed to Leo Hendrik Baekeland sold the first one called Bakelite in 1909 [citation needed]. Throughout the twentieth century the use of plastic became extremely popular and came to replace other traditional materials in both the domestic, industrial and comercial.Propiedades and Features [edit] Plastic bags Coca-Cola bottle plastic. Plastics are composed of organic macromolecules substances called polymers. These polymers are large groups of monomers linked by a chemical process called polymerization. Plastics provide the necessary balance of properties that can not be achieved with other materials such as: color, light weight, nice touch and resistance to environmental degradation and biologica.De fact, plastic refers to a condition of the material, but not material itself: synthetic polymers commonly called plastics are actually synthetic materials that can reach the plastic state, ie when the material is viscous or fluid, and has properties of resistance to mechanical stress. This state is reached when the material becomes solid plastic state usually by heating, and is ideal for different production processes and that this state is when the material can be handled in the forms that exist today. So the word plastic is a way to refer to synthetic materials capable of entering into a plastic state, but plastic is not necessarily the group of material that is routinely referred palabra.Son characteristic properties of most plastics, but not always met in certain special plastic: They are cheap (they have a low cost in the market). densidad.Existen They have low permeable and impermeable plastic material, dissemination of materials electricos.Son termoplasticos.Son insulating thermal insulation, but most do not elevadas.Su resist burning temperatures contaminante.Son is resistant to corrosion and be at the intemperie.Resisten many factors are recycled quimicos.Algunos better than others, they are not biodegradable or easy to trabajar.Procesos easy reciclar.Son development [edit] The first part of the production of plastics is the production of polymers in the chemical industry. Today, the recovery of post-consumer plastic is also essential. Part of the industry-finished plastic directly used as grain or resin. More often, they use various forms of molding (injection, compression, rotation, inflation, etc..) Or the extrusion of profiles or wires. Part of the largest plastics processing machinery is made in a plastics horneadora.Clasificacion [edit] You can qualify for the plastics into several categories: According to the base monomer [edit] This classification is considered the origin of the monomer which partly polimero.Naturales production: They are polymers whose monomers are derived from natural products with certain characteristics, eg, cellulose, casein, and rubber. In two of these examples there are others which come plastics: cellulose derivatives are: the celluloid, cellophane and rubber products cellon.Los are rubber and ebonita.Sinteticos: Those that can be traced man-made products, mainly derived from its conduct in relation to petroleo.segun calor.Termoplasticos [edit] A thermoplastic is a plastic which, at room temperature is plastic or deformable, melts to a liquid when heated and hardens a glassy state when cooled sufficiently. Most thermoplastics are high molecular weight polymers, those with associated chains via weak Van der Waals forces (polyethylene); strong dipole-dipole interactions and hydrogen bonding, or even stacked aromatic rings (polystyrene). Thermoplastic polymers differ from thermosetting polymers that after being heated and molded to form they can overheat and other objects, as in the case of thermoset or thermoduric, its shape after cooling does not change and the preferred fire .. Its physical properties change gradually if they melt and mold several veces.Los are: cellulosic resins: derived from cellulose, the material component of the woody part of plants. Belongs to this group rayon.Polietilenos and derivatives used as raw materials for ethylene obtained from oil cracking, discussed later, produces various monomers like vinyl acetate, vinyl alcohol, vinyl chloride, etc.. This part of PVC, polystyrene, methacrylate, etc.Derivados of proteins: They belong to this group, nylon and Perlon, obtained from the rubber diamidas.Derivados: Examples of this group called commercially pliofilmes , obtained by adding rubber hydrochlorides hydrochloric acid polymers caucho.Termoestables [edit] The thermosetting plastics are materials once they have undergone the process of heating-melting-solidification and training, they become rigid materials do not melt again . Generally for their recovery from a phenol aldehido.Polimeros: plastics are hard, insoluble and infusible but if used during manufacture an excess of phenol, obtained termoplasticos.Resinas epoxi.Resinas melaminicas.Baquelita.Aminoplasticos: Polymers urea and derivatives. Belongs to this group melamina.Poliesteres: Resins from esterification of polyols, which are commonly used in varnishes. If the acid is in excess, we obtain the synthesis reaction termoplasticos.Segun [edit] They may be classified according to the reaction that produced the polymer: Polymers addition [edit] always involve breaking or opening of a monomer binding to allow the formation of a chain. As the molecules are longer and heavier paraffinic wax becomes harder and more tenacious. Example: 2n H2C = CH2? [-CH2-CH2-CH2-CH2-] nPolimeros condensation [edit] are those in which the reaction takes place between the reactive functional groups present in the monomers. Must have at least two groups reactive monomer to give continuity to the chain. Example: R-COOH + R'-OH? R-CO-OR '+ H2O.Polimeros formed by stages [edit] The polymer chain is gradually growing as long as monomers available, adding one monomer at a time. This category includes all Carothers condensation polymers and also some other small molecules that do not liberate but build up gradually, such as trained poliuretanos.Polimeros chain reaction [edit] Each individual chain polymer is formed at high speed and then becomes inactive, despite being surrounded by its molecular structure monomero.Segun [edit]. Amorphous [edit] are amorphous plastics in which the molecules do not submit any order, are arranged randomly without responding to any order. With no order between chains are created some gaps through which light passes, therefore amorphous polymers are transparentes.Semicristalinos [edit] The semi-crystalline polymers have areas with some kind of order with amorphous areas. In this case to have an order there are fewer gaps between chains so no light passes unless they have a thickness pequeno.Cristalizables [edit] As the cooling rate can be lowered (rapid cooling) or increase (slow cooling) the percentage of crystallinity of a semicrystalline polymer, however, an amorphous polymer, crystallinity although not present cooling rate is extremely lenta.Segun the market [edit] Another way to classify it according to availability and the market sector it supplies. commodities [edit] They are those who have a manufacture, availability, and global demand, have a range of international prices and do not require high technology for its manufacturing and engineering procesamiento.De [edit] Are the materials used in very specific virtually created to serve a particular function, they require specialized technology to manufacturing or processing and relative price alto.Elastomeros or rubbers [edit] Elastomers are characterized by their high elasticity and the ability to stretch and rebound, recovering its original form a After withdrawing the force that deformed. They include natural and synthetic rubber, among the latter are neoprene and polybutadiene. Elastomers are materials of large molecules which after being deformed at room temperature, recover more of its size and geometry to be released the force that plastic deformo.Codificacion [edit] There are a variety of plastics and to classify them there a coding system shown in Table 1. The products bear a mark that is the international symbol for recycling with the corresponding code in the middle by material especifico.Tabla 1. International code for the different plastics. Plastic Type: Polyethylene Terephthalate High Density Polyethylene Polyvinyl Chloride Low Density Polyethylene Polypropylene Polystyrene Common Uses [edit] electrico.Aplicaciones Used as insulation in industrial and consumer products. (Packaging, garbage bags ,...). Construction, plumbing, insulation foam, polystyrene, etc.Industrias number: engine parts, body, toys, luggage, sporting goods, textiles, etc. In electricos.Reciclaje artifacts [edit]. Baskets for classification of waste that could be reciclados.Es easy to see how plastic waste, eg packaging of liquids such as cooking oil, are not likely to be assimilated back into nature, because his material takes approximately degradarse.Ante 500 years this fact has been established recycling such plastic products, which mainly consisted of collecting them, cleaning, sorting by type of material and melt again for further use as feedstock, alternative or substitute for other productos.De molding this way mankind has found a way as to avoid contamination of products depending on its composition, materials or components are not easily disposed of convencional.Plastico reciclado.Reciclar plastico.Se can save large amounts of nonrenewable natural resources when the production processes used materials "recycled." Renewable resources like trees, can also be saved. The use of recycled products reduces energy consumption. When you use less fossil fuels would generate less CO2 and thus will be less acid rain and reduce the effect invernadero.En the financial side, one can say that recycling can generate many jobs. It takes a great work force to collect the materials suitable for recycling and for classification. A good recycling process is able to generate income. For the foregoing reasons, it is imperative to improve and introduce new technologies in terms of recovery processes for plastics and seek a solution to this problem so harmful to society and that every day is increasing environmental deterioration. The following sections are considered the design of a smelter for low density polyethylene, its use, its features, recommendation and impact will provide the biodegradable comunidad.Plasticos [edit] In the late twentieth century the price of oil dropped, and fell just as interest in biodegradable plastics. In recent years this trend has reversed as well be an increase in the price of oil, has been a growing realization that oil reserves are being depleted at an alarming rate. Within this context, there is a marked increase in scientific and industrial interest in research to produce biodegradable plastics or PDEs (environmentally degradable polymers and plastics). The manufacture of biodegradable plastics from natural materials, is one of the great challenges in various sectors, industrial, agricultural, and materials for various services. Against this background, research involving the plastics obtained from other sources have taken a new momentum and the polyhydroxyalkanoates are highly prometedora.La as an alternative replacement of current plastics for biodegradable plastics is a means by which the polluting effect of those , would be diminished in the environment. Biodegradable plastic waste can be treated as organic waste in the tanks and remove devices, where the degradation takes place in periods of time.The meager biodegradable polymers can be classified as follows: Polymer extracted or removed directly from biomass: polysaccharides as starch and cellulose. Proteins such as casein, keratin, and colageno.Polimeros produced by chemical synthesis using classical biological monomers renovables.Polimeros sources produced by microorganisms, bacteria producing native or modified geneticamente.Dentro the last category are biodegradable plastics produced by bacteria in this group found the PHAs and polylactic acid (PLA). The PHAs due to their origin from renewable sources and the fact of being biodegradable, are called "doubly green polymers." The PLA, natural monomer produced by fermentative pathways from elements rich in sugars, cellulose and starch, is polymerized by man. Bioplastics have identical physicochemical properties and the thermoplastic polymer made from petroleum, but once placed in favorable conditions, biodegradan.Acido polylactide (PLA). Starch is a natural polymer, a high carbohydrate that synthesized during photosynthesis plants that serves as an energy reserve. Cereals such as corn and wheat contain large amounts of starch and are the main source for the production of PLA. Bioplastics produced from this polymer has the characteristic of a resin that can be injected, extruded and production of this biopolymer termoformarse.La begins with starch extracted from corn, then microorganisms transform it into a smaller molecule of lactic acid or 2 hydroxy-propionic (monomer), which is the raw material that polymerizes to form chains, with a molecular structure similar to the products of petrochemical origin, which are joined together to form a plastic called PLA is one of PLA.El biodegradable plastics currently most studied, is available on the market since 1990. It is used in the manufacture of transparent bottles cold drinks, food packaging trays, and many other aplicaciones.Polihidroxialcanoatos.Historia.Los PHAs are usually produced by Gram-negative bacteria, although Gram-positive bacteria are also producing a lesser scale. The first PHA discovered was the PHB, which was described at the Pasteur Institute in 1925 by microbiologist Lemoigne who observed the production of PHB by Bacillus megaterium. Subsequently, in 1958 Wildinson Macrae and Bacillus megaterium noted that the polymer accumulated when glucose / nitrogen in the culture medium was not observed in equilibrium and its degradation when there was lack or deficiency of carbon or energy sources. From this fact, PHA inclusions were found in a wide range of bacterial species. At present about 150 different known polihidroxialcanoatos.La PHB first patent was requested in the United States by J. N. Baptist in 1962. In 1983 there were two major events, first was the discovery by De Smet, a strain of Pseudomonas oleovorans (ATCC 29 347) producing PHB, and running the first production was the first commercial use biopoliester. A copolymer formed by monomers of four and five-carbon, known as PHB and PHV, respectively, this product is known commercially as "Biopol" generated using Ralstonia eutropha, from glucose and propionic acid. This bioplastic at present and is synthesized from a single carbon source in recombinant bacteria, and has a high potential for biodegradability and thermomechanical properties better than the general puro.En PHB PHAs are insoluble in water, biodegradable, nontoxic, therefore one of the main benefits gained from the application of PHAs is environmental. The use of these products, reduce dependence on oil from the plastic industry, causes a decrease of solid waste reduction and observe the emission of gases that cause the effect invernadero.Los points of interest regarding applications bioplastics, according to the IBAW (International Working Group and Biodegradable Polymers) focus on the areas of packaging, medicine, agriculture and disposable products. However, with the advancement of this industry has expanded the use of biomaterials applied in: Cell phones, computers, audio and video devices. According to this information has been established that 10% of plastics currently used in the electronics industry can be replaced by biopolimeros.Problemas related to recycling [edit] In modern life the plastic has been a phenomenon of undoubted importance . Today man lives surrounded by plastic objects in previous centuries were not necessary for everyday life. Plastics are manufactured to meet the demands of a wide variety of applications, resulting in a vast industry where civilization should be called the civilization of plastic, due to the decisive role played by this material in their development, improvement of conditions of human life and the rapid growth of science and tecnologia.En general, people have little knowledge about what is a plastic, how to get, what kinds of plastics and its applications, we are transformation processes of the same. This information is important for those working in the marketing of plastics, and industrial production or processing of plastic, or just curious about the matter. Thus arises as a need in this project show a significant proportion of the population of the serious consequences of misuse of plastic that goes from the manner of collection, to the processes used to reciclarlos.Cabe noted that the plastic is a substance very important for the development of the industry and its natural or synthetic material containing as essential ingredients organic substances of high molecular mass polimero.Asi call itself arises as a problem associated with environmental pollution often waste product of plastics and high low density. Currently, these plastics are widely used commercially as containers or wrappers, food substances or articles which are discarded into the environment after use. Obviously the disposal of these plastics into the environment with serious consequences for communities such as diseases among which is the dengue produced by the accumulation of garbage and sewage stagnation they serve as mosquito breeding sites white legs. Among other important consequences can be mentioned are the blockages of sewers. In addition to this the disposal of these plastic materials into the environment causes decreased beautification of some areas, facilities, municipalities, cities and estados.Muchas of the advantages of plastic products becomes a disadvantage when it comes to either discard the packaging because it is decarteble or when we throw plastic objects because they are well roto.Si plastics could be reused or recycled in the most part, the fact is that today these wastes are a difficult problem, mainly in large cities. It is really a costly and complex for the municipalities responsible for the collection and disposal of waste and that the amount of packaging you must add the volume plastics representan.Por characteristics create problems in the collection, transfer and disposal final. Some data are alerting us to this. For example, a truck with a capacity to carry 12 tons of common waste, transported only 6 or 7 tons of compacted plastic, and only 2 plastic without compactar.Dentro of total disposable plastic will now trash is emphasized in the recent years, the sustained increase in PET containers, primarily from disposable bottles of table water, oils and alcoholic and non alcoholic. The firms have been replacing glass containers for returnable plastic at first, and then non-returnable. This decision implies a permanent change in the composition of the waste. In Uruguay this process has accelerated since mid-1996, worsened in 1997 when, in addition, many glass containers of glass became descartable.De this way, it is clear that the abandonment of these materials into the environment represents a serious environmental problem. Therefore, there is the concern of developing a team with the ability to recover these plastics that have been discarded by society, which are considered non reusables.De purpose thus arises as to design a computer that uses induction heat melting the polyethylene low density are held in the same, once fused, bonded and become liquid discharges into a mold to develop other products to be used in other material aplicaciones.Un candidate to replace oil is hemp, usable all uses petrochemicals, but it is also 100% biodegradable and highly recyclable.
Plastic
From Wikipedia, the free encyclopedia
Jump to: navigation, search
The term plastic in its broader meaning applies to substances of different structures that lack a fixed point of boiling and held over a temperature range elasticity and flexibility properties that allow mold them and adapt to different forms and applications. However, in the narrow sense, is that denotes certain types of synthetic materials obtained by polymerization phenomena or artificial propagation of carbon atoms in the long molecular chains of organic compounds derived from petroleum and other natural substances.
The word plastic was originally used as an adjective to denote a degree of mobility and easy to acquire some form, meaning that remains in the term plasticity.
History
The invention of the first plastic arises as a result of a competition held in 1860, when the U.S. manufacturer of billiard balls and Collard Phelan offered a reward of $ 10,000 who get a substitute for natural ivory, for the manufacture of billiard balls . One of the people who competed was the American inventor John Wesley Hyatt, who developed the film dissolving cellulose (natural material) in a solution of camphor and ethanol. While Hyatt did not win the prize, got a very marketable product that would be vital for the further development of the film industry of late nineteenth-s.
In 1909 American chemist Leo Hendrik Baekeland Belgian origin synthesized a polymer of high commercial interest, from molecules of phenol and formaldehyde. It gave the name of bakelite and was the first totally synthetic plastic ever, was the first of a series of synthetic resins, which revolutionized modern technology by starting the "plastic era." Throughout the twentieth century the use of plastic became extremely popular and came to replace other materials in both the domestic, industrial and commercial.
In 1920 there was an event that would set the pace in the development of plastics. The German chemist Hermann Staudinger ventured that they were in fact composed of giant molecules or macromolecules. Efforts to test these claims initiated many scientific research that produced enormous advances in this part of chemistry.
Properties and characteristics
Plastic bags.
Plastic bottle.
Plastics are organic substances formed by macrocells called polymers. These polymers are large groups of monomers linked by a chemical process called polymerization. Plastics provide the necessary balance of properties that can not be achieved with other materials such as: color, light weight, nice touch and resistance to environmental and biological degradation.
In fact, plastic refers to a condition of the material, but not the material itself: the synthetic polymers commonly called plastics are actually synthetic materials that can reach the plastic state, ie when the material is viscous or fluid, and no resistance properties to mechanical stress. This state is reached when the material becomes solid plastic state usually by heating, ideal for different production processes and that this state is when the material can be handled in the forms that exist today. So the word plastic is a way to refer to synthetic materials capable of entering into a plastic state, but plastic is not necessarily the group of everyday materials to which this word refers.
The properties and characteristics of most plastics (though not always fulfilled in certain special plastics) are these:
* Easy to work and shape,
* Have a low production cost,
* Have low density
* Tend to be waterproof,
* Good electrical insulators,
* Acceptable acoustic insulation,
* Good thermal, although most can not withstand very high temperatures
* Resistant to chemical corrosion and many factors;
* Some are not biodegradable or easily recyclable, and if they are burned, are highly polluting.
Production Process
The first part of the production of plastics is the production of polymers in the chemical industry. Today, the recovery of post-consumer plastic is also essential. Part of the industry-finished plastic directly used as grain or resin. More often, they use various forms of molding (injection, compression, rotation, inflation, etc..) Or the extrusion of profiles or wires. Part of the largest plastics processing is done on a machine horneadora.
Classification of plastics
According to the base monomer
This classification is considered the origin of the monomer from which part of the polymer production.
* Natural: These are polymers whose monomers are derived from natural products with certain characteristics, eg, cellulose, casein, and rubber. In two of these examples there are other plastic which is obtained from:
or cellulose derivatives are: the celluloid, cellophane and Cellon.
o rubber products are the rubber and ebonite.
* Synthetic: Those that have their origin in man-made products, mainly petroleum products such as polyethylene bags
According to their behavior in heat
Thermoplastics
A thermoplastic is a plastic that, at room temperature, is plastic or deformable, it becomes a liquid when heated and hardens into a glassy state when cooled sufficiently. Most thermoplastics are high molecular weight polymers, those with associated chains via weak Van der Waals forces (polyethylene); strong dipole-dipole interactions and hydrogen bonding, or even stacked aromatic rings (polystyrene). Thermoplastic polymers differ from thermosetting polymers that after being heated and molded to form they can overheat and other objects, as in the case of thermoset or thermoduric, its shape after cooling does not change and the preferred fire ..
Its physical properties change gradually if they melt and shape several times.
The main ones are:
* Cellulosic Resins: derived from cellulose, the material component of the woody part of plants. Belongs to this group rayon.
* Polyethylenes and derivatives used as raw materials for ethylene obtained from oil cracking, discussed later, allows for different monomers such as vinyl acetate, vinyl alcohol, vinyl chloride, etc.. This part PVC, polystyrene, acrylic, etc.