Although the fundamental property of bulk polymers is the degree of polymerization, the physical structure of the chain is also an important factor that determines the macroscopic properties.
The terms configuration and conformation are used to describe the geometric structure of a polymer and are often confused. Configuration refers to the order that is determined by chemical bonds. The configuration of a polymer cannot be altered unless chemical bonds are broken and reformed. Conformation refers to order that arises from the rotation of molecules about the single bonds. These two structures are studied below.
The two types of polymer configurations are cis and trans. These structures can not be changed by physical means (e.g. rotation). The cis configuration arises when substituent groups are on the same side of a carbon-carbon double bond. Trans refers to the substituents on opposite sides of the double bond. Stereoregularity is the term used to …show more content…
Nylon is an alternating copolymer with 2 monomers, a 6 carbon diacid and a 6 carbon diamine. The following picture shows one monomer of the diacid combined with one monomer of the diamine: Cross-Linking
In addition to the bonds which hold monomers together in a polymer chain, many polymers form bonds between neighboring chains. These bonds can be formed directly between the neighboring chains, or two chains may bond to a third common molecule. Though not as strong or rigid as the bonds within the chain, these cross-links have an important effect on the polymer. Polymers with a high enough degree of cross-linking have "memory." When the polymer is stretched, the cross-links prevent the individual chains from sliding past each other. The chains may straighten out, but once the stress is removed they return to their original position and the object returns to its original
The first term that I noted during the movie was Conductive Polymers. Conductive polymers are almost always organic meaning a large class of chemical compounds whose molecules contain carbon. These polymers have extended delocalized bonds which are bonds found in a molecule that do not belong to a single atom or covalent bond. They are conjugated systems of double bonds and in a aromatic systems. The conjugated systems are atoms covalently bonded with alternating single and double bonds. When the electrons are removed or added into the valence bands the electrical conductivity increases. The conductive polymer has a low conductivity until the electron is removed from the valence band called (p-doping) or (n-doping) until it becomes more conductive. The movement of the charges is what is responsible for electrical conductivity. These polymers are plastic which are organic polymers and with mechanical properties such as flexibility and elasticity.
The purpose of this experiment was to create a polymer by reacting a mixture of decanedioyl dichloride and dichloromethane with a mixture of water, 1,6-hexadiamine and sodium carbonate. Specifically, we created the polymer Nylon-6,10. Nylon-6,10 polymers are used in a vast majority of things we use in everyday life such as zippers, the bristles in brushes, and even car parts. This experiment was different from the industrial method of making nylon because that takes place at a much higher temperature. A polymer is a substance that has a structure made of similar or identical units bonded together. All polymerizations fall into two categories: step-growth and chain-growth (both of which we used to form our polymer). Step growth polymerization
Polymer chains are long, individual chains, although they behave as if they are attached to each other. The individual chains are actually held together by ‘Electrostatic Forces’ between molecules, also known as ‘Hydrogen Bonds’. Scientists discovered this, by using a special type of X-ray microscopy called ‘XANES’. This was able to reveal the orientation of molecules in materials. It has also been discovered that the components of Kevlar fiber, have a radial orientation that is in a crystal. The crystal-like regularity is the largest contributing factor in the strength of Kevlar fiber.
They are covalent in nature and this property enhance their stability than the physically cross linked counterparts. The monomers are copolymerizing for the preparation of chemically cross linked microgels in the presence of multifunctional cross linking
There are two types of synthetic polymers which are called condensation and addition polymers. The condensation polymers result when there is a reaction between two poly functional molecules which gets rid off a small molecule. For example, the polyester Dacron is a synthetic condensation polymer. Addition polymers on the other hand are formed in a domino effect including monomers with double bonds. Once the polymers are formed they tend to take on a linear shape or a star/comb like shape and then they are classified as linear and branched polymers. There are four major biological macromolecules which are carbohydrates, lipids, proteins and nucleic acids. Carbohydrates are sugar molecules that are made from C, H and O in a 1:2:1 ratio. Monosaccharides and disaccharides are carbohydrates divided into simple sugars while polysaccharides are carbohydrates that are divided into complex sugars such as starch. Lipids are substances like fat and phospholipids are important components of all living creatures. They are hydrophobic and thus it is difficult to break down to form energy. Biological polymers are made of amino acids, nucleotides and sugars. A significant biological polymer
This maximises the intermolecular forces between the chains as they are able to pack closely together. However, this reduces the flexibility and is therefore quite rigid and strong. This isotactic polyvinyl chloride structure occurs very little. Another structure that is produced very little is the syndiotactic PVC. The syndiotactic PVC has a regular arrangement and has similar properties of flexibility, rigidity and strength to the isotactic PVC as shown in Figure #.
Liquid crystalline solution are also form in Lyotropic main chain liquid crystalline polymers. In case of Lyotropic main chain liquid crystalline polymers, liquid crystalline solution formed due to the spatial arrangement of the main chain of polymer, not due to the substituent character on polymer main chain. An example of such a polymer is poly (-benzyl-L-glutamate). (Edmir Silva, 2010)
however, is a synthetic fiber. It is a polyamide whose molecular chains are formed by regularly
A single Kevlar polymer chain could have anywhere from five to a million segments bonded together. Each Kevlar segment or monomer is a chemical unit that contains 14 carbon atoms, 2 nitrogen atoms, 2 oxygen atoms and 10 hydrogen atoms. The hydrogen bonds greatly strenghten the polymer chain.
Monomers that are combined by condensation polymerization have two functional groups. A carboxylic acid and an amine can form an amide linkage, and a carboxylic acid and an alcohol can construct an ester linkage. So as each monomer has two reactive sites, they can form long chain polymers by making multiple amide or ester links and releasing a small molecule. Examples of the mentioned mechanism are illustrated below.
Polystyrene is a thermoplastic polymer which is the third most important polymer which is synthetically prepared from the styrene of monomers which is petrochemical liquid. It can be hard or can b soft foamed. It is inexpensive resin that’s why it is clear, brittle and hard. The excellent processing and physical properties make this thermoplastic material very suitable that’s why it is used in many applications. It is a vinyl polymer which has long hydrocarbon chain and phenyl group attached to every other carbon atom. It is formed or produced by polymerization of vinyl which should be a free radical. This polystyrene is a component of type of hard rubber which is also called poly(styrene-butadiene-styrene). Polystyrene will take more volume in landfill than paper and enter the environment again and again when water or any mechanical force breach landfills. We can also say that it performed many functions as a monomer which is to be found in many different polymers. As estimated that the 17-21 million tons of polystyrene is produced yearly.
Polymer-Polyethylene is partially crystalline as well as amorphous because it has crystalline and amorphous regions. Also it has linear chains so this is the simplest structure compared to a branched or network chain. This can be of an advantage to it over other types of materials as its good toughness and elongation makes it very significant in the engineering industry as it can be moulded or extruded into shape...
chains instead of hydrogen atoms. Cross-linking is another way in which the polymer can be made stronger. This involves ultraviolet radiation that bombards the polymer with electrons and formulates bonds between the molecular chains of the polymers. This is like linear polyethylene but different in that it is more impact resistant, and it has a much higher density. This allows it to be stored or be used with different chemicals that would normally cause the polymer to desolve.3 This can start to become a problem because as the polymer continues to become chemically enhanced. So the ways of dissolving and recycling the polymer become more difficult.
POLYMER RELATED FACTORS: Molecular weight: For linear polymers, mucoadhesion increases with molecular weight. A large molecular weight is essential for entanglement; however, excessively long polymer chains lose their ability to diffuse and interpenetrate mucosal surfaces. Concentrated dispersions are retained on the mucous membrane for longer periods. After application such systems spread easily, since they present rheological properties of a liquid, but gellify as they come in contact with the absorption site, thus preventing their rapid removal. Chain flexibility is critical for interpenetration and entanglement with the mucus gel. Increased chain mobility leads to increased inter-diffusion and interpenetration of the polymer within the mucus
A polymer is a large molecule that is known as an organic compound. Polymers are used in many different ways to form different structures but mostly polymers are used to create various kinds of plastics. A polymer is made from the covalent bonding of smaller repetitive molecules. As seen in figure 1. These repeating molecules are built into chains, and different polymers have varied chain lengths. These smaller molecules which make up the polymer are known as monomers. Through the reaction of polymerization which generally requires a catalyst polymers are formed. Various Polymers are built of different types of monomers, some contain only one type of monomer whereas others can contain up to two or more monomers. These polymers are known as natural polymers, they occur in nature and then are extracted for use. Natural polymers are often water based, examples are silk,