project maker
07-08-2014, 11:12 AM
Plastic
[attachment=66690]
Introduction:
Plastic is the general common term for a wide range of synthetic or semisynthetic organic amorphous solid materials used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce costs. Monomers of Plastic are either natural or synthetic organic compounds.
The word is derived from the Greek πλαστικός (plastikos) meaning fit for molding, and πλαστός (plastos) meaning molded. It refers to their malleability, or plasticity during manufacture, that allows them to be cast, pressed, or extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and much more.
The common word plastic should not be confused with the technical adjective plastic, which is applied to any material which undergoes a permanent change of shape (plastic deformation) when strained beyond a certain point. Aluminium, for instance, is plastic in this sense, but not a plastic in the common sense; in contrast, in their finished forms, some plastics will break before deforming and therefore are not plastic in the technical sense.
There are two types of plastics: thermoplastics and thermosetting polymers. Thermoplastics will soften and melt if enough heat is applied; examples are polyethylene, polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE). Thermosets can melt and take shape once; after they have solidified, they stay solid.
Overview
Plastics can be classified by chemical structure, namely the molecular units that make up the polymer's backbone and side chains. Some important groups in these classifications are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics can also be classified by the chemical process used in their synthesis, such as condensation, polyaddition, and cross-linking.
Other classifications are based on qualities that are relevant for manufacturing or product design. Examples of such classes are the thermoplastic and thermoset, elastomer, structural, biodegradable, and electrically conductive. Plastics can also be classified by various physical properties, such as density, tensile strength, glass transition temperature, and resistance to various chemical products.
Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to water, plastics are used in an enormous and expanding range of products, from paper clips to spaceships. They have already displaced many traditional materials, such as wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their former uses.
The use of plastics is constrained chiefly by their organic chemistry, which seriously limits their hardness, density, and their ability to resist heat, organic solvents, oxidation, and ionizing radiation. In particular, most plastics will melt or decompose when heated to a few hundred degrees celsius.While plastics can be made electrically conductive to some extent, they are still no match for metals like copper or aluminium. Plastics are still too expensive to replace wood, concrete and ceramic in bulky items like ordinary buildings, bridges, dams, pavement, and railroad ties
Cellulose-based plastics
In 1855, an Englishman from Birmingham named Alexander Parkes developed a synthetic replacement for ivory which he marketed under the trade name Parkesine, and which won a bronze medal at the 1862 World's fair in London. Parkesine was made from cellulose (the major component of plant cell walls) treated with nitric acid and a solvent. The output of the process (commonly known as cellulose nitrate or pyroxilin) could be dissolved in alcohol and hardened into a transparent and elastic material that could be molded when heated. By incorporating pigments into the product, it could be made to resemble ivory.
Bois Durci is a plastic moulding material based on cellulose. It was patented in Paris by Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which gives a black or brown resin. The mixture is dried and ground into a fine powder. The powder is placed in a steel mould and compressed in a powerful hydraulic press whilst being heated by steam. The final product has a highly polished finish imparted by the surface of the steel mould.
Rubber
Natural rubber is an elastomer (an elastic hydrocarbon polymer) that was originally derived from latex, a milky colloidal suspension found in the sap of some plants. It is useful directly in this form (indeed, the first appearance of rubber in Europe is cloth waterproofed with unvulcanized latex from Brazil) but, later, in 1839, Charles Goodyear invented vulcanized rubber; this a form of natural rubber heated with, mostly, sulfur forming cross-links between polymer chains (vulcanization), improving elasticity and durability.
Random Depolymerization:
Plastics have become an integral part and parcel of our lives due to its economic value, easy availability, easy processability, light-weight, durability and energy efficiency, besides other benefits.
Since plastics are re-usable and recyclable, there should not have been any problem of disposal of the plastics waste, however due to our poor littering habits and inadequate waste management system/infrastructure, plastics waste management, disposal continues to be a major problem for the civic authorities, especially in the urban areas.
Though various steps have already been either taken or initiated by the Government and the legal/civic authorities to reduce the problem of this waste management, an innovative invention by Prof. Alka Umesh Zadgaonkar of the Department of Applied Chemistry, G.H. Raisoni College of Engineering, Nagpur, Maharashtra, has created a hope and scope to tackle this problem more easily and more environmentally-friendly manner.
She has invented a catalyst system, which converts polymeric materials into liquid, solid and gaseous fuels.
Advantages
Reduces pollution helps in waste plastic degradation.
Cheaper and quality fuel.
Perfect solution for waste plastic, rubber, tyre management.
Raw material readily available.
Plant is energy self sufficient.
Conclusion
This study shows without doubt that one-way PET bottles are as ‘ecologically favourable’ as refillable glass under non-deposit circumstances. A plausible alternative could be to revise the Packaging Ordinance, such that ecologically favourable packaging systems would be included in a deposit without being discriminated when compared to refillable packaging. It cannot be explained to consumers that they should return the empty bottles to the store if they are
subsequently transported to the other side of the world for recycling. This way we are losing environmental gain that is the prime reason behind bottles collection. This study has shown that it does not matter whether collected PET is recycled into polyester fibre, sheet, strapping or back into PET bottles: they all offer equal benefits to the ecological profile of PET. Mandatory or semi mandatory requirements to recycle PET bottles into PET bottles would be ridiculous. Public perception does not always match reality. Not many people comprehend that PET bottles, even for single use, are as good as their glass counterparts. This calls for further improvements in balanced, reputable education, and independent and irrespective of local political
[attachment=66690]
Introduction:
Plastic is the general common term for a wide range of synthetic or semisynthetic organic amorphous solid materials used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce costs. Monomers of Plastic are either natural or synthetic organic compounds.
The word is derived from the Greek πλαστικός (plastikos) meaning fit for molding, and πλαστός (plastos) meaning molded. It refers to their malleability, or plasticity during manufacture, that allows them to be cast, pressed, or extruded into a variety of shapes—such as films, fibers, plates, tubes, bottles, boxes, and much more.
The common word plastic should not be confused with the technical adjective plastic, which is applied to any material which undergoes a permanent change of shape (plastic deformation) when strained beyond a certain point. Aluminium, for instance, is plastic in this sense, but not a plastic in the common sense; in contrast, in their finished forms, some plastics will break before deforming and therefore are not plastic in the technical sense.
There are two types of plastics: thermoplastics and thermosetting polymers. Thermoplastics will soften and melt if enough heat is applied; examples are polyethylene, polystyrene, polyvinyl chloride and polytetrafluoroethylene (PTFE). Thermosets can melt and take shape once; after they have solidified, they stay solid.
Overview
Plastics can be classified by chemical structure, namely the molecular units that make up the polymer's backbone and side chains. Some important groups in these classifications are the acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Plastics can also be classified by the chemical process used in their synthesis, such as condensation, polyaddition, and cross-linking.
Other classifications are based on qualities that are relevant for manufacturing or product design. Examples of such classes are the thermoplastic and thermoset, elastomer, structural, biodegradable, and electrically conductive. Plastics can also be classified by various physical properties, such as density, tensile strength, glass transition temperature, and resistance to various chemical products.
Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to water, plastics are used in an enormous and expanding range of products, from paper clips to spaceships. They have already displaced many traditional materials, such as wood; stone; horn and bone; leather; paper; metal; glass; and ceramic, in most of their former uses.
The use of plastics is constrained chiefly by their organic chemistry, which seriously limits their hardness, density, and their ability to resist heat, organic solvents, oxidation, and ionizing radiation. In particular, most plastics will melt or decompose when heated to a few hundred degrees celsius.While plastics can be made electrically conductive to some extent, they are still no match for metals like copper or aluminium. Plastics are still too expensive to replace wood, concrete and ceramic in bulky items like ordinary buildings, bridges, dams, pavement, and railroad ties
Cellulose-based plastics
In 1855, an Englishman from Birmingham named Alexander Parkes developed a synthetic replacement for ivory which he marketed under the trade name Parkesine, and which won a bronze medal at the 1862 World's fair in London. Parkesine was made from cellulose (the major component of plant cell walls) treated with nitric acid and a solvent. The output of the process (commonly known as cellulose nitrate or pyroxilin) could be dissolved in alcohol and hardened into a transparent and elastic material that could be molded when heated. By incorporating pigments into the product, it could be made to resemble ivory.
Bois Durci is a plastic moulding material based on cellulose. It was patented in Paris by Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which gives a black or brown resin. The mixture is dried and ground into a fine powder. The powder is placed in a steel mould and compressed in a powerful hydraulic press whilst being heated by steam. The final product has a highly polished finish imparted by the surface of the steel mould.
Rubber
Natural rubber is an elastomer (an elastic hydrocarbon polymer) that was originally derived from latex, a milky colloidal suspension found in the sap of some plants. It is useful directly in this form (indeed, the first appearance of rubber in Europe is cloth waterproofed with unvulcanized latex from Brazil) but, later, in 1839, Charles Goodyear invented vulcanized rubber; this a form of natural rubber heated with, mostly, sulfur forming cross-links between polymer chains (vulcanization), improving elasticity and durability.
Random Depolymerization:
Plastics have become an integral part and parcel of our lives due to its economic value, easy availability, easy processability, light-weight, durability and energy efficiency, besides other benefits.
Since plastics are re-usable and recyclable, there should not have been any problem of disposal of the plastics waste, however due to our poor littering habits and inadequate waste management system/infrastructure, plastics waste management, disposal continues to be a major problem for the civic authorities, especially in the urban areas.
Though various steps have already been either taken or initiated by the Government and the legal/civic authorities to reduce the problem of this waste management, an innovative invention by Prof. Alka Umesh Zadgaonkar of the Department of Applied Chemistry, G.H. Raisoni College of Engineering, Nagpur, Maharashtra, has created a hope and scope to tackle this problem more easily and more environmentally-friendly manner.
She has invented a catalyst system, which converts polymeric materials into liquid, solid and gaseous fuels.
Advantages
Reduces pollution helps in waste plastic degradation.
Cheaper and quality fuel.
Perfect solution for waste plastic, rubber, tyre management.
Raw material readily available.
Plant is energy self sufficient.
Conclusion
This study shows without doubt that one-way PET bottles are as ‘ecologically favourable’ as refillable glass under non-deposit circumstances. A plausible alternative could be to revise the Packaging Ordinance, such that ecologically favourable packaging systems would be included in a deposit without being discriminated when compared to refillable packaging. It cannot be explained to consumers that they should return the empty bottles to the store if they are
subsequently transported to the other side of the world for recycling. This way we are losing environmental gain that is the prime reason behind bottles collection. This study has shown that it does not matter whether collected PET is recycled into polyester fibre, sheet, strapping or back into PET bottles: they all offer equal benefits to the ecological profile of PET. Mandatory or semi mandatory requirements to recycle PET bottles into PET bottles would be ridiculous. Public perception does not always match reality. Not many people comprehend that PET bottles, even for single use, are as good as their glass counterparts. This calls for further improvements in balanced, reputable education, and independent and irrespective of local political