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Polymer properties depend on the chemicals that the polymer is made from and polymerization conditions that ultimately set molecular architecture: chemical linkage type, chain length, and the nature of the end groups. The type of the monomer-repeat unit that forms a polymer has a strong effect on polymer properties.
What affects polymer material properties?
The physical properties (such as transition temperature, viscosity, etc.) and mechan- ical properties (such as strength, stiffness, and toughness) depend on the molecular weight of polymer. The lower the molecular weight, lower the transition temperature, viscosity, and the mechanical properties.
What causes polymers to have different properties?
Why do different polymers have different properties? Answer: They have different chemical compositions (different monomer units), different structures, different ways of being fabricated, etc.
What is the properties of polymers?
Some of the useful properties of various engineering polymers are high strength or modulus to weight ratios (light weight but comparatively stiff and strong), toughness, resilience, resistance to corrosion, lack of conductivity (heat and electrical), color, transparency, processing, and low cost.
What are polymers based on?
Polymers are materials made of long, repeating chains of molecules. The materials have unique properties, depending on the type of molecules being bonded and how they are bonded. Some polymers bend and stretch, like rubber and polyester. Others are hard and tough, like epoxies and glass.
What are the properties and uses of polymers?
Uses of polymers Polymer Properties Uses Poly(chloroethene) ‘PVC’ Tough, electrical insulator, can be made hard or flexible Insulation for electrical wires, windows, gutters, pipes Poly(tetrafluoroethene) ‘PFTE’ Slippery, chemically unreactive Non-stick coatings for pans, containers for laboratory substances.
What are the mechanical properties of polymer?
Polymer Chemistry: Mechanical Properties Tensile Strength. % Elongation to Break. Young’s Modulus. Toughness.
What are the three main properties of polymers?
Heat capacity/ Heat conductivity. The extent to which the plastic or polymer acts as an effective insulator against the flow of heat. Thermal expansion. The extent to which the polymer expands or contracts when heated or cooled. Crystallinity. Permeability. Elastic modulus. Tensile strength. Resilience. Refractive index.
How can we change the properties of polymers?
Overall, the main ways to change and tune the properties of a polymer include changing the length of the polymer chains, creating branched chains from linear polymer chains, crosslinking the polymer chains and adding plasticizers into the polymer.
What is cross linking How does it change the property of polymers?
Cross-linking Rubber and some other polymers can be cross-linked. A chemical reaction takes place that connects the chains to each other permanently. This makes the whole structure more rigid and less elastic. It also makes the material a lot stronger and harder.
What are 4 types of polymers?
Synthetic polymers are human-made polymers. They can be classified into four main categories: thermoplastics, thermosets, elastomers, and synthetic fibers. They are commonly found in a variety of consumer products.
What are the advantages of polymers?
Polymers are more resistant to chemicals than their metal counterparts. Polymer parts do not require post-treatment finishing efforts, unlike metal. Polymer and composite materials are up to ten times lighter than typical metals. Polymers are naturally radar absorbent as well as thermally and electrically insulating.
What are the two types of polymers?
Polymers fall into two categories: thermosetting plastic or thermoset. thermoforming plastic or thermoplastic.
What are polymers and its types?
Commercial Uses of Polymers Polymer Monomer Uses of Polymer Rubber Isoprene (1, 2-methyl 1 – 1, 3-butadiene) Making tyres, elastic materials BUNA – S (a) 1, 3-butadiene (b) Styrene Synthetic rubber BUNA – N (a) 1, 3-butadiene (b) Vinyl Cyanide Synthetic rubber Teflon Tetra Flouro Ethane Non-stick cookware – plastics.
Why are polymers so strong?
The bigger the molecule, the more molecule there is to exert an intermolecular force. Even when only weak Van der Waals forces are at play, they can be very strong in binding different polymer chains together. This is another reason why polymers can be very strong as materials.
How do you classify polymers?
The most common way of classifying polymers is to separate them into three groups – thermoplastics, thermosets, and elastomers. The thermoplastics can be divided into two types – those that are crystalline and those that are amorphous.
What are the advantages and disadvantages of polymers?
They have relatively low melting and degredation temperatures, so this can be a limit for use at high temperatures. Some of polymers can degrade on sunlight and some of radiations. Strength and hardness is low compared with ceramics and metals. Modulus of elasticity or stiffness is generally low in polymers.
What are examples of polymers?
Examples of synthetic polymers include nylon, polyethylene, polyester, Teflon, and epoxy. Natural polymers occur in nature and can be extracted. They are often water-based. Examples of naturally occurring polymers are silk, wool, DNA, cellulose and proteins.
How do polymers work?
When monomers join with other monomers through the process of creating covalent bonds, they form larger molecules, called polymers. If it bonds with three or more molecules then three-dimensional, cross-linked structures can form [source: Innovate Us]. Polymers can occur naturally, or we can manufacture them.
What are the electrical properties of polymer?
Electrical Properties of Polymers Dielectric Constant/Dissipation Factor ASTM D150, IEC 60250. Dielectric Strength ASTM D149, IEC 243-1, IEC 60243. Volume Resistivity ASTM D257, IEC 60093. Surface Resistivity ASTM D257, IEC 60093.
What are mechanical properties?
Mechanical properties are physical properties that a material exhibits upon the application of forces. Examples of mechanical properties are the modulus of elasticity, tensile strength, elongation, hardness and fatigue limit.
What is thermal properties of polymer?
In our new poster, “Thermal Properties of Polymer Materials”, the following important values can be seen at a glance: glass transition temperature, melting enthalpy, melting temperature, decomposition temperature, modulus of elasticity, thermal expansion coefficient, specific heat, thermal conductivity and density.
What is a polymer melt?
Polymer melts are solvent-free, viscoelastic liquids consisting of entangled macromolecules with a monomer volume fraction ηm=πρmb3/6 comparable with that of simple liquids.
How does temperature affect polymers?
The effect of temperature change on polymers When substances made of small molecules are heated, they simply melt and form a free-flowing liquid; however with polymers the process is more complex. When polymers are cooled, they will often become very brittle.
How do plasticisers affect the properties of polymers?
Plasticizers are low molecular weight substances added to a polymer solution to promote its plasticity and flexibility. This is a temperature at which a polymer transforms from a hard, glassy material to a soft, rubbery material. Plasticizers lower the glass transition temperature of the polymers.
How do you strengthen polymers?
Adding filler materials such as fibers, platelets, and particles is a commonly employed technique for strengthening polymer materials. Fillers such as clay, silica, and carbon network materials have been extensively researched and used in polymer composites in part due to their effect on mechanical properties.
How are polymers manipulated?
The key to the manipulation is putting the polymer mixture into a solution with varying conditions, such as higher or lower pH or different temperatures, reports ScienceDaily. In the solution, polymers tend to move away from each other if they are attracted to the molecules in the solvent.
What does cross-linking polymers do?
Polymer chemistry. Crosslinking is the general term for the process of forming covalent bonds or relatively short sequences of chemical bonds to join two polymer chains together. Intermediate cross-link densities transform gummy polymers into materials that have elastomeric properties and potentially high strengths.
How does cross-linking increase the strength of polymers?
7.24 Explain how cross linking improves the strength of polymers. o Crossed linked polymers contain additional bonds between the molecules that provide resistance to flow. All of the extra links or bonds must be broken before the molecules can move relative to each other. Some polymers are conductive naturally.
