Polymers are complex groupings of molecules bonded into long chains. This unique molecular structure can give them properties such as high strength, durability, or flexibility that make them extremely useful for a wide variety of applications. All plastic engineering relies on creating polymers.
Because of the complexity and wide-ranging utility of these structures, polymer testing has become a vital quality assurance technique. By subjecting polymer-based products to a suite of tests, experts can determine whether a polymer is suitable for its intended use and how it will react to different environmental stimuli.
This is what you should know about polymers and polymer testing.
What are polymers?
Polymers are a category of material created when a series of small “building block” molecules called monomers join into long chains of repeating combinations via covalent bonding.
Each link of the polymer chain may also have secondary structures of molecular groupings called “pendent groups” branching off them. Pendent group attachments can also connect to form “crosslinks.” A polymer’s pendent groups and crosslinks determine how a polymer interacts with itself and its environment.
Polymers can be either natural or synthetic. Natural polymers include hemp, cotton, silk, natural rubber, cellulose, plant starch, and even protein and DNA. Synthetic polymers include hydrocarbons and materials like polyethylene.
Why are polymers important?
When many monomers bond into a chain, the force they exert on the resulting material they hold together becomes very strong. This affects the physical properties of polymer materials in several ways.
For example, the binding structure of synthetic polymers used in plastics gives plastic material strength and durability relative to its mass, all without losing the flexible properties of the monomers themselves.
The result is a plastic material that is uniquely durable and flexible – because the monomers are flexible, but the bond between them is difficult to break. By utilizing the properties different polymer structures make possible, manufacturers can engineer polymer-based materials for very specific and diverse use cases.
For example, all plastics manufacturing involves polymer engineering. Altering the monomers and bonds between repeat units and pendent groups in the polymers present in plastic material allows plastic manufacturers to achieve different combinations of strength, flexibility, and plasticity.
What is polymer testing?
Polymer testing refers to any scientific test conducted to determine the physical, mechanical, or chemical properties of polymers. These tests ensure that polymer-based products possess the exact properties required for their intended use.
Because different polymers can have so many different properties and applications, polymer testing tends to be broader and more complex than most quality assurance processes.
Why is polymer testing important?
Polymers are relatively complex materials used to accomplish a huge variety of tasks. Even small, subtle alterations in the composition of a polymer can have a huge effect on its ability to perform tasks up to the necessary standard and performance criteria.
If something happens during polymer manufacturing that alters the composition of the resulting material in any way, the consequences can be dangerous. Worse, they’re often not immediately apparent without significant testing. For example, if something goes wrong during plastic manufacturing, the resulting product could fail to have the necessary tensile strength to perform its intended function – even though it would still look the same as a plastic that could.
How does polymer testing work?
Several scientific tests are required to test polymers based on what analysts need to determine about their properties. The experts at Innovatech primarily rely on four different polymer testing techniques in our work. They are:
Fourier Transform Infrared Spectroscopy (FTIR)
FTIR is a form of material analysis technique designed to identify organic and inorganic contaminants within a material and to understand how they are affecting that material’s performance.
FTIR works by shining a beam of infrared radiation at many different wavelengths over a polymer sample. The molecules within the polymer each absorb the wavelengths at different rates, which produces a spectrum of infrared frequencies. Analysts can check the output against a reference library to confirm the polymer’s molecular composition.
Innovatech uses FTIR on polymers when we need to know information about their molecular structure. It can be quite helpful for determining what polymers a plastic product consists of and what else has been added to the plastic along with them.
Differential Scanning Calorimetry (DSC)
DSC is a thermal quality testing technique used to measure changes in heat flow as a sample transforms from one state to another.
During DSC testing, analysts place a polymer sample inside an isolated chamber along with a control medium. Then they subject the inside of the chamber to different temperatures. This allows us to measure the difference in temperature between the sample and control medium and understand how the polymer sample releases heat in response to phase shift.
Polymers are very susceptible to swings in temperature, which makes DSC testing an important way to understand how different polymer products will react to changing temperature conditions. DSC can help us find the melting point, enthalpy, heat capacity, glass transition temperature, percent crystallinity, and more.
Thermal Gravimetric Analysis (TGA)
TGA measures how the weight of a sample changes as it is heated or cooled in a controlled environment over time.
During TGA, analysts place the polymer sample in a temperature-controlled environment with an oven and a scale. They turn on the oven to apply fixed amounts of heat to the sample over time then monitor weight changes using the scale.
TGA testing helps us understand how polymer samples react to heat over time. We can use TGA to understand how a polymer’s components will oxidize, volatilize, or decompose under enough heat exposure. TGA is also a good way to determine how much filler was added to a polymer-based product.
Electron Spectroscopy Chemical Analysis (ESCA)
ESCA, also known as X-ray Photoelectron Spectroscopy (or XPS), helps analysts determine the molecular and chemical composition of a polymer-based material’s surface so we can understand important information about the polymer’s bonds.
ESCA works by passing an x-ray beam over the surface of the polymer sample to “excite” the atoms on its surface. When excited, atoms release core electrons that emit onto the surface of the sample where they can be detected and measured by testing equipment. Each element requires a different, specific amount of x-ray “energy” before it will release its core electrons, so by measuring that energy, we can determine the elements present on the surface of the sample.
ESCA helps us gain a great deal of specific information about the surface chemistry of polymer-based products. We can use this information to deduce how the material will react to a wide range of environments and uses.
If you think you need polymer testing, Innovatech is ready to help. Get in touch with our experts today and we’ll determine the testing techniques that are right for your product.
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