Many fundamental properties that can be changed with 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.
How do you change the properties of a polymer?
Nov 10, 2021 · 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 affects the properties of polymers? Polymer properties depend on the chemicals that the polymer is made …
What are the major chemical changes in polymerization?
What can also change the properties of a polymer that is produced? Many fundamental properties that can be changed with 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 .
How does length affect the properties of a polymer?
Colorant pigments for polymers. Fillers: Filler additives are added to composition of polymers to obtain more fibrious and reduce the cost of material. Mechanical properties of polymers are also enhanced with fillers. Polymers that mechanical properties are enhanced with fillers, called as ‘reinforced platics’.
What parameters can be controlled during the polymerization reaction?
Polymers are found in nature. These include starch and cellulose. Polymers are also man made. These include plastics, synthetic fiber such as nylon and synthetic rubber. In this project, the student will attempt to change the properties of this polymer. In the process, the student will be using the scientific method by first formulating a ...
What affects the properties of polymers?
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 causes polymers to have different properties?
The way molecules are arranged gives different polymers different properties. By manipulating the molecular arrangement, different polymers can be created—depending on whether you want a material that's strong, stretchy, recyclable or whatever. Polyethylene, for example, has long polymer chains side by side.Jan 30, 2017
Which bonds change the property of a polymer?
Polymers consist of very long molecules that contain chains of carbon. They too are held together by very strong covalent bonds. There are greater intermolecular forces between the long chains compared with smaller simple molecules. This means that polymers have a higher melting point than many other organic molecules.
Is it possible to 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.Aug 14, 2019
How do different polymers have different properties?
Because of the structure of the molecules, polymeric materials have different properties compared to other materials, like metals. Specifically, the relatively high molecular weight and long polymer chain length result in entanglement, and the lack of covalent intermolecular bonds facilitates polymer chain mobility.
What are 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 bonds do polymers have?
Polymers are held together by primary bonds (covalent bonds) and secondary bonds (van der Waals and hydrogen bonds). In covalent bonding there is a sharing of valence electrons (the s and p shells) to complete an octet (a group of eight electrons) around atoms.
What can impact the physical properties of a polymer?
The main factors that change their properties are temperature, chain length, side groups, branching and cross linking.May 1, 2011
What are polymer properties?
Polymer properties depend of their structure and they are divided into classes according to their physical basis. Many physical and chemical properties describe how a polymer behaves as a continuous macroscopic material. They are classified as bulk properties, or intensive properties according to thermodynamics .
What are the forces that determine the properties of a polymer?
The attractive forces between polymer chains play a large part in determining the polymer’s properties. Because polymer chains are so long, they have many such interchain interactions per molecule, amplifying the effect of these interactions on the polymer properties in comparison to attractions between conventional molecules. Different side groups on the polymer can lend the polymer to ionic bonding or hydrogen bonding between its own chains. These stronger forces typically result in higher tensile strength and higher crystalline melting points.
How to determine polymer composition?
Polymer characterization spans many techniques for determining the chemical composition, molecular weight distribution, and physical properties. Select common techniques include the following: 1 Size-exclusion chromatography (also called gel permeation chromatography ), sometimes coupled with static light scattering, can used to determine the number-average molecular weight, weight-average molecular weight, and dispersity. 2 Scattering techniques, such as static light scattering and small-angle neutron scattering, are used to determine the dimensions ( radius of gyration) of macromolecules in solution or in the melt. These techniques are also used to characterize the three-dimensional structure of microphase-separated block polymers, polymeric micelles, and other materials. 3 Wide-angle X-ray scattering (also called wide-angle X-ray diffraction) is used to determine the crystalline structure of polymers (or lack thereof). 4 Spectroscopy techniques, including Fourier-transform infrared spectroscopy, Raman spectroscopy, and nuclear magnetic resonance spectroscopy, can be used to determine the chemical composition. 5 Differential scanning calorimetry is used to characterize the thermal properties of polymers, such as the glass-transition temperature, crystallization temperature, and melting temperature. The glass-transition temperature can also be determined by dynamic mechanical analysis. 6 Thermogravimetry is a useful technique to evaluate the thermal stability of the polymer. 7 Rheology is used to characterize the flow and deformation behavior. It can be used to determine the viscosity, modulus, and other rheological properties. Rheology is also often used to determine the molecular architecture (molecular weight, molecular weight distribution, branching) and to understand how the polymer can be processed.
Why are synthetic polymers used?
Nowadays, synthetic polymers are used in almost all walks of life. Modern society would look very different without them. The spreading of polymer use is connected to their unique properties: low density, low cost, good thermal/electrical insulation properties, high resistance to corrosion, low-energy demanding polymer manufacture and facile processing into final products. For a given application, the properties of a polymer can be tuned or enhanced by combination with other materials, as in composites. Their application allows to save energy (lighter cars and planes, thermally insulated buildings), protect food and drinking water (packaging), save land and reduce use of fertilizers (synthetic fibres), preserve other materials (coatings), protect and save lifes (hygiene, medical applications). A representative, non-exhaustive list of applications is given below.
What is a polymer made of?
A polymer is a substance composed of macromolecules. A macromolecule is a molecule of high relative molecular mass, the structure of which essentially comprises the multiple repetition of units derived, actually or conceptually, from molecules of low relative molecular mass. Condensed matter physics.
What is polymerization of polymer?
Polymerization is the process of combining many small molecules known as monomers into a covalently bonded chain or network. During the polymerization process, some chemical groups may be lost from each monomer. This happens in the polymerization of PET polyester. The monomers are terephthalic acid (HOOC—C 6 H 4 —COOH) and ethylene glycol (HO—CH 2 —CH 2 —OH) but the repeating unit is —OC—C 6 H 4 —COO—CH 2 —CH 2 —O—, which corresponds to the combination of the two monomers with the loss of two water molecules. The distinct piece of each monomer that is incorporated into the polymer is known as a repeat unit or monomer residue.
Is polythylene an insulator?
Most conventional polymers such as polythylene are electrical insulators, but the development of polymers containing π-conjugated bonds has led to a wealth of polymer-based semiconductors, such as polythiophenes. This has led to many applications in the field of organic electronics .
What are polymers able to do?
From this point of view, polymers are able to show enormous versatility, so much so that materials activated by heat, electric current, application of forces, light radiation and hydration have been developed.
What is shape memory polymer?
Shape Memory Polymer belongs to the class of smart materials and are defined as those polymers that have the ability to return from a deformed state (temporary shape) to that original (permanent form) through an external stimulus. By modifying their three-dimensional structure in response to precise external stimuli, shape memory polymers allow the creation of devices with complex and miniaturized morphologies. Although the shape memory metal alloys were the first to be developed, the evolution of polymers allowed them to quickly establish themselves in the segment, so much so that the first commercial application dates back to the 1960s, with the production of cross-linked polyethylene (PE) heat shrink to be used as a pipe cover.
What temperature is PEG?
PEG (polyethylene glycol) or poly-ɛ-caprolactone, whose glass transition temperatures are around 40-60 °C, are widely used to obtain soft phases with Ttemp slightly higher than the ambient ones or those of the human body.
What is epoxy resin used for?
The importance of epoxy resins for SMP is mainly that they are used in a wide variety of protective and decorative coatings due to their good adhesion, mechanical and chemical resistance. They are applied mainly in coatings of cans and drums; coatings for car and cable paint.
What are some examples of orthodontics?
2. Shape Memory Polymers in Bandages.
Changing The Processing Parameter
Addition of Other Chemicals
- The other two ways to change the properties of a polymer are through cross-linking the polymer and the addition of plasticizers. While cross-linking is technically on the process side (in terms of changing the chemicals used), polymers only cross-link when a specific cross-linker is added during the polymerization reaction. So, it is dependent on the addition and not the process condi…
Sources and Further Reading
- Purdue University: http://chemed.chem.purdue.edu/genchem/topicreview/bp/1polymer/property.html
- Royal Society of Chemistry (RSC): http://www.rsc.org/learn-chemistry/resource/download/res00001921/cmp00006124/pdf
Overview
A polymer is a substance or material consisting of very large molecules, or macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic and natural polymers play essential and ubiquitous roles in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteinsthat are fun…
Structure
The structure of a polymeric material can be described at different length scales, from the sub-nm length scale up to the macroscopic one. There is in fact a hierarchy of structures, in which each stage provides the foundations for the next one. The starting point for the description of the structure of a polymer is the identity of its constituent monomers. Next, the microstructureessentially d…
Common examples
Polymers are of two types: naturally occurring and synthetic or man made.
Natural polymeric materials such as hemp, shellac, amber, wool, silk, and natural rubber have been used for centuries. A variety of other natural polymers exist, such as cellulose, which is the main constituent of wood and paper.
The list of synthetic polymers, roughly in order of worldwide demand, includes
History
Polymers have been essential components of commodities since the early days of humankind. The use of wool (keratin), cotton and linen fibres (cellulose) for garments, paper reed (cellulose) for paper are just a few examples of how our ancestors exploited polymer-containing raw materials to obtain artefacts. The latex sap of “caoutchouc” trees (natural rubber) reached Europe in the 16th cen…
Synthesis
Polymerization is the process of combining many small molecules known as monomers into a covalently bonded chain or network. During the polymerization process, some chemical groups may be lost from each monomer. This happens in the polymerization of PET polyester. The monomers are terephthalic acid (HOOC—C6H4—COOH) and ethylene glycol(HO—CH2—CH2—OH) but the repea…
Properties
Polymer properties depend of their structure and they are divided into classes according to their physical basis. Many physical and chemical properties describe how a polymer behaves as a continuous macroscopic material. They are classified as bulk properties, or intensive properties according to thermodynamics.
Applications
Nowadays, synthetic polymers are used in almost all walks of life. Modern society would look very different without them. The spreading of polymer use is connected to their unique properties: low density, low cost, good thermal/electrical insulation properties, high resistance to corrosion, low-energy demanding polymer manufacture and facile processing into final products. For a given application, the properties of a polymer can be tuned or enhanced by combination with other ma…
Standardized nomenclature
There are multiple conventions for naming polymer substances. Many commonly used polymers, such as those found in consumer products, are referred to by a common or trivial name. The trivial name is assigned based on historical precedent or popular usage rather than a standardized naming convention. Both the American Chemical Society (ACS) and IUPAChave proposed standardized naming conventions; the ACS and IUPAC conventions are similar but no…