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Find answers to common questions about Thermo Fisher Scientific instruments and technologies used in creating, analyzing, and manufacturing types of polymers.
A polymer is a material made of repeating molecular units (monomers) linked into long chains. Common polymers include plastics such as polyethylene and polypropylene, as well as natural materials like rubber and cellulose. Their molecular structures influence properties such as durability, elasticity, and thermal stability, which is why polymers can be engineered for a wide range of applications.
Polymers are used across many industries because their properties can be tailored through formulation and processing. Applications include but are in no way limited to the following:
Different formulations allow polymers to meet specific requirements such as flexibility, durability, chemical resistance, or thermal stability.
Polymer analysis is the measurement and characterization of materials such as plastics, resins, and composites to understand their composition, structure, and performance. It is used in research, quality control, and manufacturing to verify materials, troubleshoot issues, and support product development.
Polymer characterization is the process of measuring a material’s composition, structure, and performance to understand how it will behave in real-world applications. It is a broader concept that includes polymer analysis techniques such as spectroscopy, rheology, thermal analysis, and X-ray methods.
In practice, polymer characterization is applied across the full material lifecycle:
By combining techniques across these stages, polymer characterization connects material composition, structure, and performance, enabling more informed decisions in research, development, and manufacturing.
Polymer properties depend on formulation and processing conditions. Analytical testing helps in a number of ways:
Without reliable data, it can be difficult to maintain consistent product quality.
Polymer analysis typically combines multiple techniques, each providing different information:
Each technique provides different information, so often several are used together across laboratory and manufacturing environments to provide a more complete evaluation.
Raw materials are typically verified using Fourier transform infrared (FTIR) or near-infrared (NIR) spectroscopy to confirm identity and to detect contamination before the raw materials enter production. In many manufacturing environments, this step is used to prevent material mix-ups, which can lead to product defects or costly downtime.
Rheological measurements may also be used to confirm that the material will behave consistently during processing.
There is no single method that works for all materials. In practice, the type of information desired determines the most appropriate technique:
Using more than one technique improves reliability, especially for blends, additives, or degraded materials.
FTIR measures how a material absorbs infrared light. Different chemical bonds absorb at specific wavelengths, producing a characteristic spectrum. This spectrum is compared against known spectra in reference libraries to identify the polymer and detect organic additives or contaminants. FTIR is widely used in quality control labs and manufacturing environments because it is fast and requires minimal sample preparation.
Raman spectroscopy measures how monochromatic light is scattered at different energies by a material. The resulting spectrum is distinct to a molecule’s bonds and backbone structure. This makes Raman particularly useful for differentiating similar polymers, analyzing crystallinity, and assessing molecular order. Raman spectroscopy is also able to measure materials through packaging or in aqueous environments. This makes Raman analysis valuable for use on multilayer films, coatings, and in situ analysis.
FTIR spectroscopy is often used for rapid material identification and routine quality control, while Raman spectroscopy can provide additional structural information and is often useful for multilayer materials, aqueous samples, and applications requiring spatially resolved analysis. The most appropriate technique depends on the material, the sample environment, and the analytical objective.
X-ray diffraction (XRD) measures how X-rays interact with ordered regions in a material. Crystalline structures produce distinct diffraction patterns that can be used to characterize materials:
This makes XRD analysis especially useful for materials where mechanical strength, barrier performance, or thermal resistance depend on structure.
FTIR spectroscopy, Raman spectroscopy, and XRD analysis provide different but complementary information about polymer materials.
FTIR and Raman spectroscopy both analyze molecular vibrations, but they respond to different types of chemical bonds and environments. XRD analysis, in contrast, measures how molecules’ component atoms are arranged in space relative to one another, making it especially useful for distinguishing structural differences between materials with similar chemistry.
In practice, these techniques are often used together to build a more complete understanding. FTIR can confirm which chemical groups are present, Raman can provide additional structural details, and XRD can reveal how those structures are organized at the bulk level.
This combined approach is particularly valuable for analyzing polymer blends, multilayer materials, and materials with similar compositions but different physical properties, where a single technique may not provide enough information.
X-ray photoelectron spectroscopy (XPS) is a surface-sensitive technique used to measure elemental composition and chemical states at the outermost layers of a material.
It is used when surface properties are critical, such as in coatings, adhesives, and treated films. XPS can help evaluate surface contamination, oxidation, or chemical modification, which can affect adhesion, wettability, and performance.
XPS is often preferred when surface chemistry is important. The analytical technique can help characterize surface treatments, contamination, oxidation, coatings, and adhesion-related issues that may not be detected using bulk analytical techniques.
Contamination is identified by combining techniques:
This multi-technique approach is commonly used in failure analysis, recycling, and quality control of raw materials.
Unknown polymers are typically identified using FTIR or Raman spectroscopy, which generate a chemical fingerprint of the material. The measured spectrum is compared to known spectra in reference libraries to determine the polymer type. For more complex samples such as filled, blended, or degraded materials, additional techniques like XRD or elemental analysis may be used to confirm the result.
Quality control combines multiple analytical techniques:
These tests help verify that materials meet specifications before and during production.
Common tests include the following:
The selection depends on the application and performance requirements—for example, films, molded parts, coatings, or composites.
Common quality control techniques include FTIR or Raman spectroscopy for material identification; rheology for evaluating flow behavior; XRF for elemental analysis; and thermal analysis for stability assessment. The appropriate combination depends on the material, manufacturing process, and quality requirements.
Compounding and extrusion involve mixing, melting, and shaping polymers under controlled conditions. During these processes, changes in composition, temperature, or flow behavior can affect product quality.
Analytical techniques are used to monitor and control these processes in real time. Near-infrared (NIR) and Raman spectroscopy can track material composition, while process mass spectrometry can analyze gases released during processing. Web gauging systems measure thickness, basis weight, or coating uniformity across films and sheets.
Together, these tools can help support product consistency and process optimization in continuous manufacturing environments.
FTIR and NIR spectroscopy are commonly among the fastest methods, providing results in seconds with minimal sample preparation. These techniques are widely used for incoming material verification and in-process checks.
Yes. Many polymer manufacturing processes use inline or at-line analytical technologies to monitor materials during production and provide timely information for process control.
Here are a few examples of how different technologies may be used:
These techniques can help manufacturers identify process deviations, support process monitoring, and make informed adjustments during continuous manufacturing operations.
By identifying deviations early, analytical methods help prevent out-of-spec batches before they develop. Proper analysis also helps optimize processing conditions to reduce scrap and limit the amount of rework needed. Real-time or rapid testing also improves production efficiency. This is particularly important in high-volume processes such as packaging film production or injection molding.
Rheology measures how polymers flow and deform, which is important for several reasons:
Rheological measurements provide a realistic view of how materials behave during manufacturing.
Viscosity and flow behavior affect how a polymer will behave during operations such as extrusion, injection molding, and coating. They influence other production parameters such as die pressure, suitability for mold filling, quality of surface finish, and the risk of defects.
These properties are measured using rotational or capillary rheometers, which apply controlled stress or deformation to the material. The results of such analyses show how viscosity changes with shear rate and temperature, providing a more realistic view of how the material will behave under actual processing conditions.
Rheological measurements help characterize polymer flow behavior, elasticity, molecular structure, and structure–property relationships. These factors are all critical for optimizing processing conditions and final product performance.
Rheology helps optimize polymer formulations by identifying flow anomalies, processing limitations, and the influence of additives, branching, and molecular weight distribution on material performance. Knowing this information can empower decision-makers to alter processing conditions in ways that improve outcomes.
Melt flow index testing provides a quick measurement under a single set of conditions and is commonly used for basic quality control. Rheology evaluates flow behavior across a range of temperatures and shear rates, making it more useful for predicting processing performance during extrusion, injection molding, and other manufacturing operations.
Melt flow index (MFI), also called melt flow rate (MFR), is a simple test that measures how easily a polymer flows under a specific temperature and load. It is commonly used for incoming material checks and basic quality control because it provides a quick indication of viscosity and consistency between batches.
However, MFI represents flow at one set of conditions only, while real processing—such as extrusion or injection molding—occurs across a range of shear rates, temperatures, and stresses. As a result, two materials with the same MFI can behave differently during processing.
Rheological testing measures viscosity over a range of conditions, providing a more complete understanding of flow behavior and helping predict performance in actual manufacturing processes.
Additives such as fillers, plasticizers, and stabilizers can change viscosity, stability, and mechanical properties. Even small formulation changes can significantly affect processing and final product performance.
Knowing the rheological properties of a material before setting up a new extrusion process can help reduce development time and material consumption during process optimization, not only for new formulations but also for recycled samples.
Frequency sweep experiments can be used to gain information about the flow resistance during the extrusion process at high shear rates utilizing the so-called Cox-Merz rule. Additionally, the viscous and elastic properties represented by the storage modulus G’ and loss modulus G’’ can be determined. These parameters are directly related to the polymer structure, its molecular weight, and molecular weight distribution. All these factors influence the processing behavior of a material tremendously.
It should be noted that during the extrusion process, the main energy input is mechanical and generated by the rotation of the screw(s). In a rheometer, on the contrary, the energy input is mainly due to heating when performing oscillatory testing. Hence, rheology cannot simulate the whole extrusion process but can be used to evaluate the processing conditions to run trials at a small-scale extruder and scale-up afterward.
Yes. Rheology can be combined with FTIR or Raman spectroscopy to simultaneously monitor flow behavior and molecular or structural changes during polymer processing, curing, melting, or crystallization.
When only a few grams of material are available, micro-compounders and lab-scale parallel twin-screw extruders provide efficient small-scale compounding solutions for polymer research and formulation development.
Micro-compounders can process sample volumes starting as small as 7 mL, making them ideal for highly limited or high-value materials. They also enable simultaneous evaluation of compounding behavior and viscosity-related structural changes during processing.
Lab-scale parallel twin-screw extruders enable continuous compounding with precise dosing of liquids and solids as well as homogeneous molecular-level mixing. These systems are well suited for developing and optimizing formulations with additives and fillers while reducing material consumption, accelerating test runs, and minimizing laboratory footprint.
Micro-compounding is a small-scale polymer processing approach used to evaluate formulation and compounding behavior when only limited amounts of material are available. It is commonly used in polymer research and early-stage material development, where sample quantities may be restricted or materials are expensive.
Micro-compounding systems can process very small sample volumes while providing insight into how polymers behave during mixing and compounding under controlled shear and temperature conditions. They are used to study formulation effects, additive interactions, viscosity-related changes, and material stability during processing.
Micro-compounding is particularly valuable for developing new polymer formulations, evaluating additives and fillers, screening recycled materials, and optimizing processing conditions before scaling up to larger extrusion or manufacturing processes.
A torque rheometer is used to analyze the mixing, melting, plastification, and processing behavior of polymers under controlled shear and temperature conditions. It helps evaluate material processability and quality in both R&D and quality control environments.
Polymer extrusion behavior can be analyzed by monitoring torque, melt temperature, pressure, throughput, and shear viscosity during extrusion. Many such measurements are performed using a rheometer. Laboratory extruders also enable rheological measurements using slit or capillary dies.
Web gauging refers to inline measurement systems used to monitor properties such as thickness, basis weight, and coating uniformity in continuous materials like films, sheets, and nonwovens.
These systems are used during production to help ensure consistent product quality and to detect variations across the width of the material. Web gauging is commonly applied in packaging, coatings, and film extrusion processes.
Crystallinity describes how ordered the polymer structure is. A material’s crystallinity affects its strength and stiffness, chemical resistance, and thermal behavior.
Higher crystallinity improves stiffness and barrier performance—for example, in packaging films—while lower crystallinity improves flexibility.
Crystallinity is typically measured using X-ray diffraction (XRD), which distinguishes crystalline and amorphous regions and allows quantitative analysis.
Dynamic mechanical thermal analysis (DMTA) measures how a polymer’s mechanical properties change with temperature. It provides insight into a material’s rigidity or viscosity:
These measurements are used to understand how materials perform under real conditions such as heat, vibration, or mechanical stress.
DMTA is particularly important for specialized materials:
DMTA helps engineers evaluate stiffness, durability, and performance across the temperature range a product will experience.
The glass transition temperature (Tg) marks the point where a polymer changes from a rigid, glassy state to a more flexible, rubber-like state. It is commonly determined using DMTA or thermal methods.
Tg is a critical parameter for applications where temperature affects performance, including:
Knowing Tg helps define the usable temperature range of a material and ensures it performs as expected in its final application.
UV-Vis spectroscopy measures how a material absorbs and transmits light in the ultraviolet and visible range. It is used to evaluate optical properties such as transparency, color, and haze. It is also very useful for analyzing UV-absorbing additives.
This analytical technique is commonly applied towards packaging, coatings, and films, where optical appearance and UV stability are important. It is also used to study material changes during aging, such as discoloration or degradation from UV exposure.
In polymer applications, “failure” refers to a material no longer meeting its intended performance. This can manifest in several forms:
The most common types of failure vary by application:
Failure analysis combines multiple techniques to identify the root cause or causes:
By comparing failed and reference materials, this approach helps determine whether the issue is due to material selection, formulation changes, processing conditions, or environmental exposure.
Degradation can be brought about by a number of factors:
These factors can reduce molecular weight and change material properties.
Thermogravimetric analysis (TGA) is an analytical method that measures weight changes as a material is heated. It is used to evaluate thermal stability and composition.
TGA-IR stands for thermogravimetric analysis–infrared spectroscopy. It combines two techniques: TGA, which measures how a material’s weight changes as it is heated; and IR (infrared spectroscopy), which identifies the gases released during that heating. In a TGA-IR system, gases produced as the sample decomposes are transferred directly into an IR cell, where their chemical identity is determined. This reveals what is released (e.g., water, CO₂, organic compounds) and when it is released (temperature-dependent behavior).
By linking weight loss to chemical identity, TGA-IR provides more detailed insight than thermal analysis alone.
TGA-IR is commonly used for subtle but important evaluations:
The most useful techniques depend on the suspected failure mechanism. FTIR and Raman spectroscopy can help identify chemical changes or contamination, XRD can evaluate structural differences, TGA-IR can investigate decomposition behavior, and rheology can help assess processing-related changes. Using complementary techniques often provides a more complete understanding of root causes.
Surface properties influence how a polymer interacts with its environment and with other materials. Even when the bulk polymer remains unchanged, changes at the surface can affect performance, quality, and manufacturability.
Surface characteristics play an important role in applications involving:
Surface properties can change as a result of contamination, oxidation, plasma treatment, corona treatment, weathering, or other environmental exposure. These changes may lead to issues such as poor adhesion, delamination, coating defects, or inconsistent product performance.
Techniques such as X-ray photoelectron spectroscopy (XPS), FTIR spectroscopy, and microscopy are commonly used to characterize polymer surfaces and investigate surface-related performance issues.
Polymer surfaces and coatings are analyzed using techniques that characterize the chemical composition, structure, and condition of the outermost layers of a material. This is important because surface properties often determine how a material performs in applications involving adhesion, coating performance, printing, sealing, or environmental exposure.
Different analytical techniques provide different types of information:
These techniques are often used together to investigate issues such as poor adhesion, coating failure, delamination, inconsistent surface treatment, contamination, or changes caused by weathering and environmental exposure.
By combining chemical and physical surface characterization, manufacturers can better understand how surface properties influence product performance and process consistency.
XRF (X-ray fluorescence) spectroscopy is an analytical technique used to measure the elemental composition of a material. It works by exposing a sample to X-rays and detecting the characteristic secondary (fluorescent) X-rays emitted by the elements present.
In polymer analysis, XRF can be used to evaluate several aspects of a sample:
XRF is fast, non-destructive, and requires little to no sample preparation, making it well suited for quality control, incoming material inspection, and regulatory compliance testing.
Elemental analysis is used to detect and quantify the elements present in additives, fillers, pigments, and catalyst residues. Common examples include titanium dioxide (TiO₂), calcium carbonate, barium sulfate, talc (hydrous magnesium silicate), brominated flame retardants, and metal-based catalyst residues.
Techniques such as X-ray fluorescence (XRF) spectroscopy can measure these materials quickly and non-destructively, making elemental analysis useful for raw material verification, formulation control, contamination detection, and regulatory compliance.
By confirming that additives and fillers are present at expected levels, manufacturers can help maintain product consistency and support quality control efforts.
Surface contamination can alter the chemical properties of a polymer's outermost layer, even when the bulk material remains unchanged. Contaminants such as oils, processing residues, dust, or additives can interfere with adhesion, coating performance, printing, sealing, and bonding.
In manufacturing, surface contamination may contribute to issues such as poor coating adhesion, delamination, inconsistent surface treatment, or product defects. Analytical techniques such as XPS, FTIR, and microscopy can help identify contaminants and determine their impact on performance.
Heavy metals such as lead, cadmium, mercury, and bromine are commonly detected in plastics using X-ray fluorescence (XRF) spectroscopy. XRF is a fast, non-destructive analytical technique that measures elemental composition with minimal sample preparation.
In polymer analysis, XRF is widely used to screen raw materials, recycled plastics, and finished products for regulated substances and contaminants. It supports quality control and compliance testing for regulations such as RoHS and WEEE, particularly in industries including electronics, packaging, automotive, and consumer products.
Compliance is typically verified by analyzing a material’s composition and comparing the results to regulatory limits and industry standards. Manufacturers commonly test raw materials and finished products for restricted substances, additives, contaminants, and elemental content.
Analytical techniques such as X-ray fluorescence (XRF) are widely used to screen for regulated elements including lead, cadmium, mercury, and brominated compounds. Spectroscopy methods such as FTIR and Raman can also support identification of polymer materials and additives.
Compliance testing is commonly used to verify that materials meet regulations and standards related to electronics, packaging, automotive, medical devices, and other consumer products. Testing helps manufacturers verify material consistency, support documentation requirements, and reduce the risk of non-compliant products entering production or the supply chain.
Regulatory requirements for polymer materials vary by country, region, industry, and application. Manufacturers may need to comply with regulations related to chemical substances, product safety, food contact, environmental impact, recycling, or industry-specific performance requirements.
Here are just a few examples of regulations:
Because requirements can vary at the local, regional, national, and international levels, manufacturers typically evaluate material composition, additives, contaminants, and product performance to support compliance with applicable regulations and customer specifications.
Restricted substances are detected using analytical techniques that identify and measure specific elements or chemical compounds. For example, X-ray fluorescence (XRF) is commonly used to screen for regulated elements such as lead, cadmium, mercury, and bromine, while spectroscopic and chromatography-based methods may be used to analyze organic additives and other regulated substances.
The appropriate technique depends on the substance being evaluated and the requirements of the applicable regulation or standard.
Compliance testing helps manufacturers verify that materials and products meet applicable regulatory, customer, and industry requirements before they enter the market. It can support product quality, supply chain consistency, and documentation requirements while helping identify restricted substances, contamination, or formulation changes.
By incorporating compliance testing into quality control workflows, manufacturers can make more informed decisions about materials, processes, and product release.
Visualization techniques, including optical microscopy and imaging methods, are used to examine the physical structure of polymer materials. They can reveal defects, phase separation, filler dispersion, and contamination.
These methods are often used alongside spectroscopy and other analytical techniques to provide spatial context, helping relate material composition to structure and performance.
Multilayer polymer films are materials made by combining two or more polymer layers, each designed to provide a specific function. Here are a few common examples of multilayer polymer films:
These materials require specialized analysis because the layers are often very thin and tightly bonded, and each layer can have a different composition and function. Separating the layers physically can be difficult or may alter the material.
Multilayer films are typically analyzed using FTIR and Raman microscopy. In combination, these techniques can examine material identification and location:
This approach enables manufacturers to verify that each layer is present and correctly formulated, which is critical for performance properties such as barrier behavior, durability, and adhesion.
Polymer composites are materials made by combining a polymer matrix with reinforcing fillers such as glass fibers, carbon fibers, or mineral particles to improve strength, stiffness, or durability. Polymer nanocomposites are a subset where the fillers are at the nanometer scale (e.g., nanoclays, carbon nanotubes, graphene), enabling enhancements in mechanical, thermal, or barrier properties at lower filler loadings.
These materials are widely used across many applications, for various reasons:
Because polymer composites’ performance depends not only on composition but also on how the fillers are distributed and how they interact with the polymer, multiple analytical approaches are used:
A key factor in composite performance is the dispersion of fillers or nanoparticles. Poor dispersion can lead to defects, weak points, or inconsistent properties, while uniform dispersion improves mechanical strength, stability, and overall material performance. Analyzing mechanical properties, processing behavior, and structure together allows manufacturers to understand not just what the material contains, but how it will perform in real-world applications.
The most appropriate analytical technique depends on the specific question being addressed and the stage of the workflow.
These are some general guidelines:
Choosing the right technique is important because each method provides a different type of information. Using a method that does not match the problem may lead to incomplete or misleading conclusions—for example, measuring flow behavior would not identify a contaminant, and identifying chemistry alone may not explain a processing defect.
In practice, many polymer challenges require complementary analysis, where multiple techniques are used together to build a complete understanding. For example, FTIR or Raman can be combined with XRF to identify both organic and inorganic components; rheology can be combined with spectroscopy to connect composition with processing behavior; and TGA-IR can be used alongside FTIR or XRD to understand both decomposition and structure.
The benefit of this approach is that it connects composition, structure, and performance. This enables more accurate root-cause analysis, better material selection, and improved process optimization. Using complementary techniques reduces uncertainty and supports more confident decision-making.
Choosing an instrument depends on the analytical question, sample type, and how the data will be used. For example, FTIR spectroscopy or Raman spectroscopy may be suitable for material identification, while rheology is used to understand processing behavior and XRD is used for structural analysis.
Other important considerations include the type of samples being analyzed, the required throughput, the level of operator expertise, and whether the instrument will be used for research, quality control, or production support. In regulated environments, the ability to support compliance testing and documentation may also be required.
In many cases, laboratories use a combination of techniques to address different aspects of material performance, rather than relying on a single instrument.
Polymer analysis is used to identify, sort, and evaluate materials before they are reused. Analytical techniques help determine several polymer characteristics:
This information is critical for producing recycled materials that meet quality requirements.
Polymers in recycling streams are typically identified using FTIR or NIR spectroscopy, which can rapidly classify materials based on their chemical signatures. These techniques are often used in sorting facilities to separate plastics by type.
Raman spectroscopy may be used for more detailed analysis, especially for complex or multilayer materials.
Polymer recycling is challenging because many materials are mixed, layered, or contain additives that are not visible. Different polymers can look similar but behave very differently during processing, and contaminants or incompatible materials can reduce the quality of recycled products.
For example, mixing polyethylene (PE) with polypropylene (PP) can lead to poor mechanical properties, while additives such as pigments or fillers can affect performance and appearance.
Contamination is detected using a combination of techniques:
This detection is important because even small amounts of contamination can affect processing and final product performance.
Recycling can change polymer properties in a number of ways:
These changes can lead to reduced strength, flexibility, or processability, which is why testing is needed to assess material quality.
Manufacturers use analytical testing throughout the process of recycling to check polymer quality. This provides insights and guides potential process changes:
Techniques such as rheology, spectroscopy, and thermal analysis help evaluate whether recycled materials are suitable for their intended applications.
In a circular economy, materials are reused rather than discarded. Polymer analysis supports this in several ways:
Without reliable analysis, it may be difficult for recyclers to maintain consistent quality in recycled materials.