Properties of Polymers
A Polymer is a huge molecule also known as macromolecule composed of replicating structural units linked by chemical bonds of covalent. The renowned examples of polymers comprise of DNA, proteins and plastics. Though polymer in popular practice recommends plastic, the word in reality refers to a huge class of synthetic and natural materials with a range of purposes and properties. Polymer materials such as amber and shellac which are natural in nature have been used for centuries. Nucleic acids and proteins which are Biopolymers play important roles in biological procedures. A range of further natural polymers are available for example cellulose, which is considered as the chief constituent of paper and wood. Some ordinary polymers are Nylon, neoprene, Polyvinyl chloride, PVB, polystyrene and Bakelite. Polymers are considered in the fields of polymer physics, polymer science and polymer chemistry.
Types of properties of polymers can be generally divided into many classes based upon scale. Next to nano-micro scale properties directly explain chain itself. At an transitional mesoscopic level properties explain the morphology of the matrix polymer in space. On the macroscopic level properties explain the bulk activities of the polymer. Polymer bulk properties are sturdily dependent upon their mescoscopic behavior and structure. Properties of polymers are described as below:
· Crystallinity:
When related to polymers, the word crystalline has to some extent ambiguous usage. In few cases, the word crystalline finds indistinguishable usage to that utilized in conventional crystallography. A synthetic polymer can be lightly explained as crystalline if it comprises areas of three-dimensional ordering macromolecular length scales, generally occurring from heaping of adjacent chains or intra molecular folding. The polymers crystallinity is distinguished by their level of crystallinity, varying from zero for a totally non crystalline polymer to one for a totally theoretical crystalline polymer.
· Tensile strength:
The tensile strength of a material measures how much pressure the material will undergo before falling. This is very significant for applications which depend upon Polymer’s physical durability or strength.
· Young’s modulus of elasticity:
Young’s modulus measures the polymer’s elasticity. It is described for miniature strains as the proportion of modification of stress to strain.
· Transport properties:
Transport properties for instance as diffusivity relate to how quickly molecules shift by way of polymer matrix. These are very significant in polymers applications for membranes and films.
· Melting point:
The word melting point when related to polymers implies not a solid-liquid phase evolution but an evolution from semi-crystalline or crystalline phase towards a solid amorphous phase.
· Boiling point:
Polymer substance’s boiling point is never described as polymers get crumbled before getting boiling temperatures of theoretical.
· Temperature of Glass transition:
A particular interest factor in synthetic polymer producing is known as temperature of glass transition. The temperature of glass transition may be engineered through changing the branching degree or cross-linking within the polymer.
· Mixing behavior:
Generally mixtures of polymer are far less miscible as compared of miniature molecule materials. As molecules of polymer are greatly larger and therefore commonly have much elevated specific volumes as compared to small molecules. The amounts of molecules mixed up in a mixture of molecule are extremely less than amount of small molecule mixture.
· Chain conformation:
The space engaged through a polymer molecule is commonly uttered in terms of radius of twist and alternatively it is also uttered in terms of saturated volume.
· Branching:
Branching of polymer chains additionally influences the bulk properties of polymers. Huge branches of chain may enlarge polymer strength and toughness due to expansion of amount of entanglements per chain.
· Chemical cross-linking:
Cross linking also increases toughness and strength. Cross linking comprises of the creation of chemical bonds amongst chains.
· Inclusion of plasticizers:
Inclusion of plasticizers inclines to increase flexibility of polymer. Plasticizers are normally miniature molecules that are chemically alike to the polymer. They create gaps amongst chains of polymer for superior mobility and decreased inter chain interactions.
Thus, polymers comprises of several unique properties with its distinct characteristics.
This entry was posted on Monday, July 7th, 2008 at 12:19 pm and is filed under Polymers. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.