list of polymers and their monomers

05/05/2013, stabilized by inter-chain hydrogen bonding, 3HV = 3-hydroxyvalerate, 3HD = 3-hydroxydecanoate. ethene All these are said to be synthetic polymers. The following diagram presents one mechanism for this useful reaction. The most common termination processes are Radical Combination and Disproportionation. Homopolymers The polymers which are obtained by the polymerisation of a single type of monomer are called homopolymers. These pages are provided to the IOCD to assist in capacity building in chemical education. Polypropene, also known as polypropylene, is made up of monomer propene. BestLife At 2 to 3% crosslinking a useful soft rubber, that no longer suffers stickiness and brittleness problems on heating and cooling, is obtained. Only monomers having anion stabilizing substituents, such as phenyl, cyano or carbonyl are good substrates for this polymerization technique. Polyvinyl chloride (PVC) is the polymer of vinyl chloride. As noted above, synthetic HDPE macromolecules have masses ranging from 105 to 106 amu (LDPE molecules are more than a hundred times smaller). These include pigments for coloring, solid fibers in composites, stabilizers and plasticizers. Rubber is a member of an important group of polymers called elastomers. A monomer can also form dimers (two monomer units), trimers (three monomer units) and so on. Recognition that polymeric macromolecules make up many important natural materials was followed by the creation of synthetic analogs having a variety of properties. Three factors that influence the degree of crystallinity are: Once in the ocean, nurdles may absorb up to a million times the level of any organic pollutants found in surrounding waters. Further polymerization at the new radical site generates a side chain radical, and this may in turn lead to creation of other side chains by chain transfer reactions. Indeed, the low cost, light weight, strength and design adaptability of plastics to meet a variety of applications have resulted in strong year after year growth in their production and use, which is likely to continue. During this period no technological advancement, other than the delivery of electrical power to every home, has impacted our lives more than the widespread use of synthetic plastics in our clothes, dishes, construction materials, automobiles, packaging, and toys, to name a few. The monomer of cellulose is the C6H12O6 aldohexose D-glucose. These possibilities are demonstrated by the following equations. This property is important in applications such as gaskets and O-rings, so the development of synthetic elastomers that can function under harsh or demanding conditions remains a practical goal. This polymer is called polyethylene rather than polymethylene, (-CH2-)n, because ethylene is a stable compound (methylene is not), and it also serves as the synthetic precursor of the polymer. The many types of polymers that we lump together as plastics are, in general, inexpensive, light weight, strong, durable and, when desired, flexible. These chemicals are then purified and used to make virgin PETE. The plastic kits and covers are mostly made of synthetic polymers like polythene and tires are manufactured from Buna rubbers. Within each section, polymers are listed in alphabetical order, … This material is methyl 2-cyanoacrylate, CH2=C(CN)CO2CH3. Since carbon radicals are stabilized by substituents of many kinds, the preference for head-to-tail regioselectivity in most addition polymerizations is understandable. Virtually all of the monomers described above are subject to radical polymerization. There are similar areas in the South Pacific, the North and South Atlantic, and the Indian Ocean. Nurdles in the sea are easily mistaken for fish eggs by creatures that would very much like to have such a snack. Except for the small amount that's been incinerated–and it's a very small amount–every bit of plastic ever made still exists, unless the material's molecular structure is designed to favor biodegradation. At 25 to 35% crosslinking a rigid hard rubber product is formed. Note that in both types of termination two reactive radical sites are removed by simultaneous conversion to stable product(s). Consequently we can identify three configurational isomers of such polymers. • HDPE is a rigid translucent solid which softens on heating above 100º C, and can be fashioned into various forms including films. 34º C). The other major polysaccharide, starch, is less robust than cellulose, but in pelletized form it is now replacing polystyrene as a packing material. When placed in a medium of intermediate density, particles of different densities separate-lower density particles float while those of higher density sink. This limiting view was challenged by Hermann Staudinger, a German chemist with experience in studying natural compounds such as rubber and cellulose. Many simple hydrocarbons, such as ethylene and propylene, can be transformed into polymers by adding one monomer after another to the growing chain. At low temperatures, chain transfer reactions are rare in such polymerizations, so the resulting polymers are cleanly linear (unbranched). Both LDPE and HDPE become brittle at very low temperatures (below -80º C). Also called random copolymers. The two natural polyesters that are finding increasing use as replacements for petroleum based plastics are polylactide (PLA) and polyhydroxyalkanoates (PHA), the latter most commonly as copolymers with polyhydroxybutyrate (PHB). To this end, an identification coding system was developed by the Society of the Plastics Industry (SPI) in 1988, and is used internationally. Unfortunately, cleaning up the garbage patch is not a realistic option, and unless we change our disposal and recycling habits, it will undoubtedly get bigger. The energy potential of plastic waste is relatively significant, ranging from 10.2 to 30.7MJkgÐ1, suggesting application as an energy source and temperature stabilizer in municipal incinerators, thermal power plants and cement kilns. The most useful acetate material is the diacetate, in which two thirds of the cellulose hydroxyl groups have been esterified. Most direct copolymerizations of equimolar mixtures of different monomers give statistical copolymers, or if one monomer is much more reactive a nearly homopolymer of that monomer. Blends of PLA with polymers such as ABS have good form-stability and visual transparency, making them useful for low-end packaging applications. In chemistry, a hydrocarbon is any compound entirely composed of hydrogen and carbon molecules. We see this every day on the streets and fields of our neighborhoods, but the problem is far more dire. Golden color. The following examples of condensation polymers are illustrative. Because polymer molecules are so large, they generally pack together in a non-uniform fashion, with ordered or crystalline-like regions mixed together with disordered or amorphous domains. In contrast to P(3HB), the polymer of 4-hydroxybutyrate, P(4HB), is elastic and flexible with a higher tensile strength. Note 2: Biochemists are now capable of synthesizing copies of biopolymersthat should be named Synthetic biopolymer to make a distinctionwith true biopolymers. Figure \(\PageIndex{1}\) - Some Monomers and Their Addition Polymers, lists some … Thus, atactic polypropylene is useless as a solid construction material, and is employed mainly as a component of adhesives or as a soft matrix for composite materials. The repeating structural unit of most simple polymers not only reflects the monomer(s) from which the polymers are constructed, but also provides a concise means for drawing structures to represent these macromolecules. The urea-formaldehyde resin is a non-transparent plastic obtained by heating formaldehyde and urea. Ziegler-Natta catalysts are prepared by reacting certain transition metal halides with organometallic reagents such as alkyl aluminum, lithium and zinc reagents. Due to the chiral nature of lactic acid, several distinct forms of polylactide exist. By using small amounts of initiators, a wide variety of monomers can be polymerized. The following values of Tg have been reported. •  Coordination Catalytic Polymerization The initiator is a transition metal complex, and the propagating site of reactivity (*) is a terminal catalytic complex. Consequently, crystallinity is high and the cellulose molecules do not move or slip relative to each other. Polymerization of propylene through action of the titanium catalyst gives an isotactic product; whereas, a vanadium based catalyst gives a syndiotactic product. A float/sink process has proven useful as a first step. He formulated a polymeric structure for rubber, based on a repeating isoprene unit (referred to as a monomer). Indeed, applications of these materials as fibers, flexible films, adhesives, resistant paints and tough but light solids have transformed modern society. The replacement of flexible alkylidene links with rigid benzene rings also stiffens the polymer chain, leading to increased crystalline character, as demonstrated for polyesters (entries 1, 2 &3) and polyamides (entries 5, 6, 7 & 8). into useful products. This is appropriate because we already have given considerable attention in previous chapters to methods of synthesis of monomers and polymers, as well as to the mechanisms of polymerization reactions. The first two equations illustrate the initiation process, and the last two equations are examples of chain propagation. A partial structure for lignin is shown here. Increased crystallinity is associated with an increase in rigidity, tensile strength and opacity (due to light scattering). Note that cellulose has neither a Tm nor a Tg. Coordination polymers may contain a range of metals in the backbone, with non-covalent bonding present. Carbohydrates: molecules composed of sugar monomers. A natural resinous polymer called lignin has a cross-linked structure similar to bakelite. In the following example, the same bisphenol A intermediate used as a monomer for Lexan serves as a difunctional scaffold to which the epoxide rings are attached. Species that have been used to initiate anionic polymerization include alkali metals, alkali amides, alkyl lithiums and various electron sources. Here ethylene (ethene) is the monomer, and the corresponding linear polymer is called high-density polyethylene (HDPE). •  Radical Polymerization The initiator is a radical, and the propagating site of reactivity (*) is a carbon radical. This process is similar to radical polymerization, as demonstrated by the following equations. is generally limited to a few types, effective recycling is often best achieved with targeted waste streams. They are commonly found in a variety of products worldwide. For polyethylene, arguably the simplest polymer, this is demonstrated by the following equation. Derivatives of cellulose, such as cellulose acetate, have long served for the manufacture of films and fibers. Treatment of a cold THF solution of styrene with 0.001 equivalents of n-butyllithium causes an immediate polymerization. • Chemists also call them macro-molecules. Isoprene. oxygen, sulfur, nitrogen) inserted along to the backbone. Monomers are the building blocks of polymers. However, one of the drawbacks of polylactides for biomedical applications is their brittleness. In this article we will discuss about the natural polymers and their monomers. The high concentration of hydroxyl groups also accounts for the facile absorption of water that is characteristic of cotton. From the utility point of view they can be classified into three main categories: thermoplastics, elastomers and synthetic fibers. The physical properties of these three polymeric substances differ from each other, and of course from their monomers. 60º C), and brittle when cooled below -50º C. It swells to more than double its size in nonpolar organic solvents like toluene, eventually dissolving, but is impermeable to water. A large number of important and useful polymeric materials are not formed by chain-growth processes involving reactive species such as radicals, but proceed instead by conventional functional group transformations of polyfunctional reactants. These are defined below. The common PET bottles are made of a synthetic polymer, polyethylene terephthalate. Prior to the early 1920's, chemists doubted the existence of molecules having molecular weights greater than a few thousand. Unlike simpler pure compounds, most polymers are not composed of identical molecules. Glucose is a water soluble solid melting below 150º C. To account for the differences noted here we need to consider the nature of the aggregate macromolecular structure, or morphology, of each substance. be sent to These reactions are illustrated by the following equations. Instead of a mixed distribution of monomeric units, a long sequence or block of one monomer is joined to a block of the second monomer:   ~AAAAA-BBBBBBB~AAAAAAA~BBB~. A tragic example of this caused the space shuttle Challenger disaster. The information provided here, and the illustration on the left, come from an article by Susan Casey in They are however expensive when compared to the synthetic polymers.[2]. Examples of naturally occurring condensation polymers are cellulose, the polypeptide chains of proteins, and poly(β-hydroxybutyric acid), a polyester synthesized in large quantity by certain soil and water bacteria. The chemical properties of the polymers are derived from their monomer units, while the physical properties of polymers are different. The components of a lipid molecule are CH2 monomers in the Tail, and a carboxylic acid at it's Head End. Escaped nurdles and other plastic litter migrate to the ocean gyre largely from land. The development of materials that we now call plastics began with rayon in 1891, continuing with Bakelite in 1907, polyethylene in 1933, Nylon and Teflon in 1938, polypropylene in 1954, Kevlar in 1965, and is continuing. The abbreviations of the code are explained in the following table. Another group of polymers, characterized by a high degree of cross-linking, resist deformation and solution once their final morphology is achieved. Here ethylene (ethene) is the monomer, and the corresponding linear polymer is called high-density polyethylene (HDPE). To begin with, cellulose chains easily adopt a stable rod-like conformation. Each monomer unit adds to the growing chain in a manner that generates the most stable radical. Cellulose fibers may be bent and twisted, but do not stretch much before breaking. In some polymers, all the monomers look the same. 170 ºC) which can be molded or machined into structural components. A comparison of the properties of polyethylene (both LDPE & HDPE) with the natural polymers rubber and cellulose is instructive. The cylindroconical cyclone device, shown on the right, provides a continuous feed procedure in which the material to be separated is pumped into the vessel at the same time as the separating media. Amino-acids. There are four basic kinds of biological macromolecules: carbohydrates, lipids, proteins, and nucleic acids. Such copolymers may have improved physical properties compared with homo P(3HB). Many of the resulting polymers are largely isotactic in configuration, and have high degrees of crystallinity. Nurdles, lentil-size pellets of plastic, found in abundance where plastics are manufactured and distributed, are dispersed by wind throughout the biosphere. The back bones of common synthetic polymers such as polythene, polystyrene and poly acrylates are made up of carbon-carbon bonds, whereas hetero chain polymers such as polyamides, polyesters, polyurethanes, polysulfides and polycarbonates have other elements (e.g. • Natural (latex) rubber is an opaque, soft, easily deformable solid that becomes sticky when heated (above. Radical polymerization gives a statistical copolymer. A listing of some important addition polymers and their monomer precursors is presented in the following table. Also silicon forms similar materials without the need of carbon atoms, such as silicones through siloxane linkages; these compounds are thus said to be inorganic polymers. Polymers usually have high melting and boiling points like … HDPE is composed of macromolecules in which n ranges from 10,000 to … To take wood again as an The C5H8 monomer isoprene is a volatile liquid (b.p. This reflects the fact that above Tg they may be shaped or pressed into molds, spun or cast from melts or dissolved in suitable solvents for later fashioning. We’Re All Built from The Same Stuff: The Four Families of Biological Molecules 1. The following problems focus on concepts and facts associated with the treatment of polymer chemistry in this text. Isoprene is a natural monomer that polymerizes to form natural rubber, most often cis-1,4-polyisoprene, but also trans-1,4-polymer. Unfortunately, the potentially useful properties of raw latex rubber are limited by temperature dependence; however, these properties can be modified by chemical change. 2.Therefore, the fluorescence structural self-quenching is not a ground state interaction, but a photo-induced excited-state interaction. To use this device Click Here. Many polymers are named by their basic monomer unit with the prefix poly. This cold-drawing procedure organizes randomly oriented crystalline domains, and also aligns amorphous domains so they become more crystalline. Finally, a random arrangement of substituent groups is referred to as atactic. As a result, the morphology of LDPE is an amorphous network of highly branched macromolecules. A terpolymer of acrylonitrile, butadiene and styrene, called ABS rubber, is used for high-impact containers, pipes and gaskets. Most plastics crumble into ever-tinier fragments as they are exposed to sunlight and the elements. PDLA and PLLA form a highly regular stereocomplex with increased crystallinity. Strong acids, such as HClO4 , or Lewis acids containing traces of water (as shown above) serve as initiating reagents. For example, styrene and acrylonitrile copolymerize in a largely alternating fashion. The unexpectedly low temperatures on the morning of the launch were below this Tg, allowing hot rocket gases to escape the seals. Acetate fibers loose strength when wet, and acetate clothing must be dry cleaned. The North Atlantic Subtropical Gyre is known as the Sargasso Sea. Some familiar household synthetic polymers include: Nylons in textiles and fabrics, Teflon in non-stick pans, Bakelite for electrical switches, polyvinyl chloride (PVC) in pipes, etc. As crystallinity increases, so does Tm. The double bonds in monomers break … At temperatures above Tg, a thicker than desired fiber can be forcibly stretched to many times its length; and in so doing the polymer chains become untangled, and tend to align in a parallel fashion. In situations that require a high level of impact strength, the toughness of PLA in its pristine state is often insufficient. 4-Hydroxybutyrate (4HB) is produced from 1,4-butanediol by microorganisms such as Aeromonas hydrophila, Escherichia coli , or Pseudomonas putida. The synthesis of macromolecules composed of more than one monomeric repeating unit has been explored as a means of controlling the properties of the resulting material. In the anionic polymerization of styrene described above, a reactive site remains at the end of the chain until it is quenched. If the polymer chain is drawn in a zig-zag fashion, as shown above, each of the substituent groups (Z) will necessarily be located above or below the plane defined by the carbon chain. Because of their high melting point and poor solubility in most solvents, Kevlar and Nomex proved to be a challenge, but this was eventually solved. Depending upon the microorganism, many of which are genetically engineered for this purpose, and the cultivation conditions, homo- or copolyesters with different hydroxyalkanic acids may be generated. One example of this radical polymerization is the conversion of styrene to polystyrene, shown in the following diagram. When exposed to water, amines or other nucleophiles, a rapid polymerization of this monomer takes place. Example of Polymers are:-1). Recycling of such mixtures is a challenging problem. Lactic acid has a chiral center, the (S)(+)-enantiomer being the abundant natural form (L-lactic acid). Synthetic polymers are human-made polymers derived from petroleum oil. Copolymers of P(3HB) and P(4HB) are synthesized by Comamonas acidovarans. The following examples refer to a two component system, in which one monomer is designated A and the other B. Several different techniques for preparing block copolymers have been developed, many of which use condensation reactions (next section). It remains an open question whether it's more energy and cost efficient to use biodegradable plastic or to recycle petroleum-based plastic. That polymer is made of molecules of sugar joined together. one electron withdrawing and the other electron donating), and both have similar reactivities toward radicals. The plastic trash from most households, even with some user separation, is a mixture of unidentified pieces. Named the "Great Pacific Garbage Patch", this stew of trash is composed largely (80%) of bits and pieces of plastic that outweigh the plankton 6 : 1, in a region over twice the size of Texas. Since larger molecules in a sample weigh more than smaller molecules, the weight average Mw is necessarily skewed to higher values, and is always greater than Mn. Clock-wise circulation of currents driven by the global wind system and constrained by surrounding continents form a vortex or gyre comparable to a large whirlpool. The above definitions of molecular weight … Most of the polymers described above are classified as thermoplastic. Here the monomeric units are distributed randomly, and sometimes unevenly, in the polymer chain:   ~ABBAAABAABBBABAABA~. It is useful to distinguish four polymerization procedures fitting this general description. The most abundant natural monomer is glucose, which is linked by glycosidic bonds into the polymers cellulose, starch, and glycogen. The nature of cellulose supports the above analysis and demonstrates the importance of the third factor (iii). Because these polymers, once formed, cannot be reshaped by heating, they are called thermosets .Partial formulas for four of these will be shown below by clicking the appropriate button. Ethylene, the common monomer for these polymers, is a low boiling (-104º C) gas. •  Cationic Polymerization The initiator is an acid, and the propagating site of reactivity (*) is a carbocation. 3. As noted earlier, HDPE is composed of very long unbranched hydrocarbon chains. Monomers are single atoms or small molecules that bind together to form polymers, macromolecules that are composed of repeating chains of monomers. Thus, instead of consigning all plastic trash to a land fill, some of it may provide energy by direct combustion, and some converted for reuse as a substitute for virgin plastics. As the weight dispersion of molecules in a sample narrows, Mw approaches Mn, and in the unlikely case that all the polymer molecules have identical weights (a pure mono-disperse sample), the ratio Mw / Mn becomes unity. UNESCO – EOLSS SAMPLE CHAPTERS FUNDAMENTALS OF CHEMISTRY – Vol. stone age, bronze age and iron age). Low-density polyethylene (LDPE) High-density polyethylene (HDPE) Polypropylene (PP) … They're light enough to blow around like dust and to wash into harbors, storm drains, and creeks. One serious problem in recycling is posed by the many additives found in plastic waste. Then, What is monomer? In these cases, the physically oriented morphology is stabilized and retained in the final product. 2. The polymers which are formed by linking monomer units, without the any change of material, are known to as addition polymers or also called as chain-growth polymers. Placing such materials in a landfill results in a slower anaerobic decomposition, which produces methane, a greenhouse gas. Kevlar and Nomex are extremely tough and resistant materials, which find use in bullet-proof vests and fire resistant clothing. 5. Most monomers of this kind, including propylene, vinyl chloride, styrene, acrylonitrile and acrylic esters, prefer to join in a head-to-tail fashion, with some randomness occurring from time to time. with a resulting decrease in Tg. PLA materials are currently used in a number of biomedical applications, such as sutures, stents, dialysis media and drug delivery devices.

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