There is also a large vocabulary used to describe the nature of the monomers and the precise arrangement of these monomers relative to one another, A polymer consisting of exactly one type of Monomer, such as poly styrene , is classifed as a homopolymer.
Polymers with more than one variety of monomer are called copolymers, such as ethylene-vinyl acetate. Some biological polymers are composed of a variety of different but structurally related monomers, such as polynucleotides composed of nucleotide subunits. A polyelectrolyte molecule is a polymer molecule comprised of primarily ionizable repeating subunits. An ionomer molecule is also ionizable, but to a lesser degree, The simplest form of polymer molecule is a straight chain or linear polymer, composed of a single main chain.
A branched polymer. Special types of branched polymers include star polymers, comb polymers, and brush polymers. If the polymer contains a side chain that has a different composition or configuration than the main chain the polymer is called a graft or grafted polymer. A cross-link suggests a branch point from which four or more distinct chains emanate.
A polymer molecule with a high degree of crosslinking is referred to as a polymer network. Macroscopic description The macroscopic physical properties of polymers in many cases reflect that of any other molecular substance.
Polymer materials may be transparent, translucent, or opaque, and may be insulators, conductors, or semiconductors. Other properties, however, especially those governing phase transitions, may have distinct meanings or no meaning at all when applied to polymers.
Among synthetic polymers, crystalline melting is only discussed with regards to thermoplastics, as thermosetting polymers will decompose at high temperatures rather than melt. The boiling point of a polymer substance is never defined, in that polymers will decompose before reaching assumed boiling temperatures. A parameter of particular interest in synthetic polymer manufacturing is the glass transition temperature T, , which describes the temperature at which amorphous polymers undergo a second order phase transition from a rubbery, viscous amorphous solid to a brittle, glassy amorphous solid.
The glass transition temperature may be engineered by altering the degree of branching or cross-linking in the polymer or by the addition of plasticizer. During the polymerization process, some chemical groups may be lost from each monomer. This is the case, for example, in the polymerization of PET polyester. The essential difference between the two is that in chain growth polymerization, monomers are added to the chain one at a time only, whereas in step-growth polymerization chains of monomers may combine with one another directly.
However, some newer methods such as plasma polymerization do not fit neatly into either category, Synthetic polymerization reactions may be carried out with or without a catalyst. Laboratory synthesis of biopolymers, especially of proteins, is an area of intensive research.
In living cells, they may be synthesized by enzyme-mediated processes, such as the formation of DNA catalyzed by DNA polymerase. The synthesis of proteins. The protein may be modified further following translation in order to provide appropriate structure and functioning Modification of natural polymers Many commercially important polymers are synthesized by chemical modification of naturally occurring polymers. Prominent examples include the reaction of nitric acid and cellulose to form nitrocellulose and the formation of vulcanized rubber by heating natural rubber in the presence of sulfur.
Polymer properties Polymer properties are broadly divided into several classes based on the scale at which the property is defined as well as upon its physical basis. The most basic property of a polymer is the identity of its constituent monomers. A second set of properties, known as microstructure, essentially describe the arrangement of these monomers within the polymer at the scale of a single chain. Chemical properties, at the nano-scale, describe how the chains interact through various physical forces.
At the macro-scale, they describe how the bulk polymer interacts with other chemicals and solvents. Monomers and repeat units The identity of the monomer residues repeat units comprising a polymer is its first and most important attribute. Polymer nomenclature is generally based upon the type of monomer residues comprising the polymer.
Polymers that contain only a single type of repeat unit are known as homopolymers, while polymers containing a mixture of repeat units are known as copolymers.
Poly styrene , for example, is composed only of styrene monomer residues, and is therefore classified as a homopolymer. Ethylene-vinyl acetate, on the other hand, contains more than one variety of repeat unit and is thus a copolymer. Some biological polymers are composed of a variety of different but structurally related monomer residues; for example, polynucleotides such as DNA are composed of a variety of nucleotide subunits, A polymer molecule containing ionizable subunits is known as a polyelectrolyte or ionomer.
Microstructure The microstructure of a polymer sometimes called configuration relates to the physical arrangement of monomer residues along the backbone of the chain. These are the elements of polymer structure that require the breaking of a covalent bond in order to change.
Structure has a strong influence on the other properties of a polymer. For example, two samples of natural rubber may exhibit different durability, even though their molecules comprise the same monomers.
Polymer architecture Branch point in a polymer An important microstructural feature determining polymer properties is the polymer architecture. The simplest polymer architecture is a linear chain: a single backbone with no branches.
A related unbranching architecture is a ring polymer. A branched, polymer molecule is composed of a main chain with one or more substituent side chains or branches. Special types of branched.
More From Shiromani Bujdil. Shiromani Bujdil. Make the volume of Resin in test tube one equal to 5 mL. Repeat all the steps and keep this set at room temperature. Unreactive to Acids. Epoxy is a copolymer; that is, it is formed from two different chemicals. These are referred to as the "resin" and the "hardener". The resin consists of monomers or short chain polymers with an epoxide group at either end. Most common epoxy resins are produced from a reaction between epichlorohydrin and bisphenol-A, though the latter may be replaced by similar chemicals.
When these compounds are mixed together, the amine groups react with the epoxide groups to form a covalent bond. Each NH group can react with an epoxide group, so that the resulting polymer is heavily crosslinked, and is thus rigid and strong.
The process of polymerization is called "curing", and can be controlled through temperature and choice of resin and hardener compounds; the process can take minutes to hours.
Some formulations benefit from heating during the cure period, whereas others simply require time, and ambient temperatures. Its synthesis requires high activation energy but the reaction is kinetically very fast.
Polystyrene It cures faster at higher concentrations of the catalyst. The strength of the polymer was independent of the concentration ratio of the resin and catalyst. Epoxy Resin It cures faster at high concentrations of its catalyst. It also cures faster at higher temperature.
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Difficulty Beginner Intermediate Advanced. Explore Documents. Polymers: Chemistry Project. Uploaded by Atul Singh Arora. Document Information click to expand document information Description: This is the project report for my chemistry project I did in the year Hope its useful. Did you find this document useful? Is this content inappropriate? Report this Document. Description: This is the project report for my chemistry project I did in the year Flag for inappropriate content. Download now.
Related titles. Carousel Previous Carousel Next. Jump to Page. Search inside document. Polystyrene 7 3. Acknowledgments I am very greatful to my chemistry teacher, Ms. Polymers Synthesis and Property Analysis Aim of the Project The aim of this project is to find out the optimum conditions for synthesis of the following polymers, 1. Bakelite Brief Description Bakelite is a material based on the thermosetting phenol formaldehyde resin, developed in — by Belgian Dr.
Formalin is an irritant to the skin, eyes, and mucous membranes. Phenol is toxic via skin contact. It is listed as a carcinogen. Glacial acetic acid is an irritant and can cause burns on contact. Materials Needed Chemicals: Apparatus: 1. Chemistry Behind it Phenol and Formaldehyde react in the following manner to make the polymer. Styrene may pose health risks if it comes in contact with the body.
Styrene resin is sticky, so use gloves. Chemistry Behind it The chemical makeup of polystyrene is a long chain hydrocarbon with every other carbon connected to a phenyl group the name given to the aromatic ring benzene, when bonded to complex carbon substituents. The hardner, Triethylenetetramine may cause allergic reactions.
Wear gloves at all times. Both the chemicals are sticky so avoid contact with bare hands. Stop Watch Take 4 clean, numbered test tubes and to each add 3mL of Resin. Unreactive to Acids Chemistry Behind it Epoxy is a copolymer; that is, it is formed from two different chemicals. Nageshwar Bhadoria. Prashant Shakya. Daniel Sangrelobo. Florine Cleary. Vinay A Iyer. Prem Kumar. Garima Jain. Patricia Joseph. Mergu Bala Raju. The Polymer library is in maintenance mode.
For new development, we recommend Lit. The Polymer library provides a set of features for creating custom elements. These features are designed to make it easier and faster to make custom elements that work like standard DOM elements. Similar to standard DOM elements, Polymer elements can be:.
Custom elements. Registering an element associates a class with a custom element name. The element provides callbacks to manage its lifecycle. Polymer also lets you declare properties, to integrate your element's property API with the Polymer data system.
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