Composition

                            Most plastics contain organic polymers. The vast majority of these polymers are based on chains of carbon atoms alone or with oxygen, sulfur, or nitrogen as well. The backbone is that part of the chain on the main "path" linking a large number of repeat units together. To customize the properties of a plastic, different molecular groups "hang" from the backbone (usually they are "hung" as part of the monomers before the monomers are linked together to form the polymer chain). The structure of these "side chains" influence the properties of the polymer. This fine tuning of the repeating unit's molecular structure influences the properties of the polymer.

        Most plastics contain other organic or inorganic compounds blended in. The amount of additives ranges from zero percentage (for example in polymers used to wrap foods) to more than 50% for certain electronic applications. The average content of additives is 20% by weight of the polymer.

        Many of the controversies associated with plastics are associated with the additives. Organotin compounds are particularly toxic.
Fillers: 

        Fillers improve performance and/or reduce production costs. Stabilizing additives include fire retardants to lower the flammability of the material. Many plastics contain fillers, relatively inert and inexpensive materials that make the product cheaper by weight.

        Typically fillers are mineral in origin, e.g., chalk. Some fillers are more chemically active and are called reinforcing agents. Other fillers include zinc oxide, wood flour, ivory dust, cellulose and starch.
Plasticizers: 

        Since many organic polymers are too rigid for particular applications, they are blended with plasticizers (the largest group of additives), oily compounds that confer improved rheology.
Colorants

        Colorants are common additives, although their weight contribution is small.

History of plastic


The development of plastics has evolved from the use of natural plastic materials (e.g., chewing gum, shellac) to the use of chemically modified, natural materials (e.g., natural rubber, nitrocellulose, collagen, galalite) and finally to completely synthetic molecules (e.g.,bakelite, epoxy, polyvinyl chloride). Early plastics were bio-derived materials such as egg and blood proteins, which are organic polymers. In 1600 BC, Mesoamericans used natural rubber for balls, bands, and figurines.  Treated cattle horns were used as windows for lanterns in the Middle Ages. Materials that mimicked the properties of horns were developed by treating milk-proteins (casein) with lye.

        In the 1800s, as industrial chemistry developed during the Industrial Revolution, many materials were reported. The development of plastics also accelerated with Charles Goodyear's discovery of vulcanization to thermoset materials derived from natural rubber.

        Parkesine is considered the first man-made plastic. The plastic material was patented by Alexander Parkes, In Birmingham, UK in 1856. It was unveiled at the 1862 Great International Exhibition in London. Parkesine won a bronze medal at the 1862 World's fair in London. Parkesinewas made from cellulose (the major component of plant cell walls) treated with nitric acid as 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.

        In 1897, the Hanover, Germany mass printing press owner Wilhelm Krische was commissioned to develop an alternative to blackboards. The resultant horn-like plastic made from the milk protein casein was developed in cooperation with the Austrian chemist (Friedrich) Adolph Spitteler (1846–1940). The final result was unsuitable for the original purpose. In 1893, French chemist Auguste Trillatdiscovered the means to insolubilize casein by immersion in formaldehyde, producing material marketed as galalith.

        In the early 1900s, Bakelite, the first fully synthetic thermoset, was reported by Belgian chemist Leo Baekeland by using phenol and formaldehyde.

        After World War I, improvements in chemical technology led to an explosion in new forms of plastics, with mass production beginning in the 1940s and 1950s (around World War II). Among the earliest examples in the wave of new polymers were polystyrene (PS), first produced by BASF in the 1930s,  and polyvinyl chloride (PVC), first created in 1872 but commercially produced in the late 1920s.  In 1923, Durite Plastics Inc. was the first manufacturer of phenol-furfural resins. In 1933, polyethylene was discovered byImperial Chemical Industries (ICI) researchers Reginald Gibson and Eric Fawcett.

        In 1954, polypropylene was discovered by Giulio Natta and began to be manufactured in 1957.

        In 1954, expanded polystyrene (used for building insulation, packaging, and cups) was invented by Dow Chemical.

        Polyethylene terephthalate (PET)'s discovery is credited to employees of the Calico Printers' Association in the UK in 1941; it was licensed to DuPont for the USA and ICI otherwise, and as one of the few plastics appropriate as a replacement for glass in many circumstances, resulting in widespread use for bottles in Europe.

Plastic introduction

Plastic introduction

Plastic is a material consisting of any of a wide range of synthetic or semi-synthetic organic compounds that are malleable and can be moldedinto solid objects. Plastics are typically organic polymers of high molecular mass, but they often contain other substances. They are usually synthetic, most commonly derived from petrochemicals, but many are partially natural. Plasticity is the general property of all materials that are able to irreversibly deform without breaking, but this occurs to such a degree with this class of moldablepolymers that their name is an emphasis on this ability.

        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. In developed countries, about a third of plastic is used in packaging and another third in buildings such as piping used in plumbing or vinyl siding. Other uses include automobiles (up to 20% plastic), furniture, and toys. In the developing world, the ratios may be different - for example, reportedly 42% of India's consumption is used in packaging. Plastics have many uses in the medical field as well, to include polymer implants, however the field of plastic surgery is not named for use of plastic material, but rather the more generic meaning of the word plasticity in regards to the reshaping of flesh.

        The world's first fully synthetic plastic was bakelite, invented in New York in 1907 by Leo Baekeland who coined the term 'plastics'. Many chemists contributed to the materials scienceof plastics, including Nobel laureate Hermann Staudinger who has been called "the father ofpolymerchemistry" and Herman Mark, known as "the father of polymer physics". The success and dominance of plastics starting in the early 20th century led to environmental concerns regarding its slow decomposition rate after being discarded as trash due to its composition of very large molecules. Toward the end of the century, one approach to this problem was met with wide efforts toward recycling.

Plastic industries

About plastic industries

Plastics engineering encompasses the processing, design, development, and manufacture of plastics products. A plastic is a polymeric material that is in a semi-liquid state, having the property of plasticity and exhibiting flow. Plastics engineering encompasses plastics material and plastic machinery. Plastic Machinery is the general term for all types of machinery and devices used in the plastics processing industry. The nature of plastic materials poses unique challenges to an engineer. Mechanical properties of plastics are often difficult to quantify, and the plastics engineer has to design a product that meets certain specifications while keeping costs to a minimum. Other properties that the plastics engineer has to address include: outdoor weatherability, thermal properties such as upper use temperature, electrical properties, barrier properties, and resistance to chemical attack.

        In plastics engineering, as in most engineering disciplines, the economics of a product plays an important role. The cost of plastic materials ranges from the cheapest commodity plastics used in mass-produced consumer products to the very expensive, specialty plastics. The cost of a plastic product is measured in different ways, and the absolute cost of a plastic material is difficult to ascertain. Cost is often measured in price per pound of material, or price per unit volume of material. In many cases however, it is important for a product to meet certain specifications, and cost could then be measured in price per unit of a property. Price with respect to processibility is often important, as some materials need to be processed at very high temperatures, increasing the amount of cooling time a part needs. In a large production run cooling time is very expensive.

        Some plastics are manufactured from re-cycled materials but their use in engineering tends to be limited because the consistency of formulation and their physical properties tend to be less consistent. Electrical and electronic equipment and motor vehicle markets together accounted for 58 percent of engineered plastics demand in 2003. Engineered plastics demand in the US was estimated at $9,702 million in 2007 and just five time more in 2019.

        A big challenge for plastics engineers is the reduction of the ecological footprints of their products. First attempts like the Vinyloopprocess can guarantee that a product's primary energy demand is 46 percent lower than conventional produced PVC. The global warming potential is 39 percent lower.