Sometimes it feels like everything is made of plastic. Innovation has expanded the application of polymer raw materials, resins, and composites, making plastic a go-to material in situations that previously would have demanded wood, metal, glass, or other naturally-derived materials. You can find plastics in toys, medical devices, clothing, food packaging — and even in things like beauty products, soda cans, and chewing gum.
With plastics as ubiquitous as they are, it’s more important than ever that manufacturers be vigilant in their quality control. Contaminants can lead to poor product performance, increase liability, and may even put your customers in danger.
Materials analysis can help ensure that materials, processes and suppliers deliver the best outcomes for your company and customers. Read on to learn ways that a quality control test for plastic can help ensure your products’ function, safety, and performance.
6 Reasons to Use a Quality Control Test for Plastics
The applications for plastics analysis aren’t limited to product failures. There are many reasons why you may wish to test the composition and chemistry of plastic materials. Here is our top five:
1. Validate Material or Supplier Changes
Changing suppliers or plastics can improve profit margins, but it’s essential to ensure that a switch doesn’t affect product quality. Materials analysis can provide information about the molecular composition and structure of a material and provide a side-by-side comparison between samples.
2. Verify New and Revised Production Process
Small tweaks to the manufacturing process can make a big difference in product performance. What happens when you increase the amount of filler or reduce the amount of plasticizer? Materials analysis can help manufacturers identify the impact of changes to ensure high-quality product performance.
3. Ensure Compliance to Specifications
If you depend on other companies for products or components, how do you verify that products are manufactured to your requirements? Materials analysis can help ensure that your suppliers use the type of plastic you specified. For example, when a client wanted to ensure that a product didn’t contain polyvinyl chloride (PVC), we used a quality control test for plastic to determine the truth.
4. Competitive Research
Materials testing can be used for reverse engineering and to provide a competitive edge. Why does this packaging keep food fresher? Why is your competitor’s product better able to withstand extreme temperatures? We can find answers to strengthen or expand your product offering.
5. Reduce Liability
Product failures and contaminants can spell big trouble for companies, especially in regulated industries like medical devices, food and beverages. A thorough material analysis can help avoid damage to your company’s brand and reputation.
6. Maintain Regulatory Compliance
Plastic testing plays an important role in helping industries maintain regulatory compliance by ensuring that plastic materials and products adhere to specific standards, regulations, and safety requirements set forth by government agencies and industry organizations.
Top Materials Analysis Techniques for Plastics
Plastics exist in many forms in the manufacturing process — polymer raw materials, resins, plastics, and composite — and we have a testing technique suitable for each substance. The following are two favorites for plastics analysis.
Fourier Transform Infrared (FTIR) Spectroscopy
FTIR analysis is often the first test used in materials testing, and polymer testing is no exception. The strength of FTIR lies in its sensitivity, simplicity, and speed. Using infrared radiation, FTIR identifies organic and some inorganic materials in sizes as small as 10-20 microns. The test is excellent at identifying surface contamination and can identify additives in a polymerwhen they can be chemically removed using solvent extraction.
FTIR case studies: Using FTIR to compare the material composition of a good part with a bad part, we zeroed in on the cause of failure. FTIR analysis was also used to uncover the reason for poor adhesion to glass bottles.
Electron Spectroscopy for Chemical Analysis (ESCA) or X-ray Photoelectron Spectroscopy (XPS)
When testing a polymer’s surface for suspected contaminants or identifying stains, ESCA (also known as XPS) is a proven choice. The test provides a detailed breakdown of the elemental composition with detection limits of ca.0.1 atomic percent, allowing easy identification of quality issues.
ESCA case studies: Learn how we used ESCA to identify the chemical composition of a stain on a polyethylene part and to analyze a haze on a polyimide film.
Ion Chromatography (IC Analysis)
Ion Chromatography is frequently used to identify and characterize impurities found in recycled polymers. IC analysis via a process called High Performance Liquid Chromatography (HPLC). The recycled polymer is dissolved into a solution and injected into a carrier liquid. Within this liquid, the sample solution’s ions are forcibly separated through a column that contains an ion-exchange resin. As the separated cations and anions flow out of the column, a conductivity detector measures the quantity of both kinds of ions and produces a readout of the data known as a chromatogram.
The chromatogram charts the peak area of each anion and cation. By comparing these peaks to a standard curve of different material concentrations available in reference charts, analysts can identify the type and quantity of contaminants in a recycled polymer. Understanding which impurities are in a recycled polymer can provide insight into how the polymer should (and should not) be used and how the impurities got there in the first place.
Thermal Gravimetric Analysis (TGA)
Thermal Gravimetric Analysis (TGA) is a type of thermal analysis that can measure a sample’s weight loss as a function of environmental temperature over time. This makes it highly useful in plastics analysis for determining the differences between polymers. For example, TGA can be used to identify the amount of inorganic filler used within a polymer, because the quantity of that filler will affect how it responds to thermal analysis.
TGA is also frequently used to study how polymers decompose over time, and specifically how much moisture they absorb during the decomposition process. During TGA, a sample of the plastic polymer is enclosed in a controlled environment containing an oven. After it’s weighed at room temperature, it is heated and monitored over time.
Depending on the type of TGA used, the sample could be heated at a constant temperature, a temperature that increases in a linear manner, or at a series of increasing temperatures. No matter how it is heated, however, the plastic sample’s response will be studied to understand how it gains or loses mass due to absorbing moisture during its decomposition process.
Differential Scanning Calorimetry (DSC)
Differential Scanning Calorimetry (DSC) has a wide variety of uses in plastics analysis. It can be used to study the phase transitions of a polymer as it converts from solid to liquid or gas, determine a polymer’s glass transition temperature and melting temperature, or study how and when the polymer crystallizes. This makes DSC a highly-useful analysis technique for plastic manufacturing quality control.
DSC is a thermal analysis procedure. It measures changes in heat flow that occur specifically as the sample being analyzed transforms from one state to another (such as solid to liquid) or undergoes other physical changes, such as crystallization or oxidation.
During DSC, a plastic sample is heated or cooled at a stable temperature alongside a reference material until the transformation the analysts want to study occurs. At this point, DSC measures the differences in heat flow between the reference material and the sample to record how the sample is absorbing or releasing heat during its phase transition. This allows analysts to understand exactly when a phase transition will occur in a plastic and how that transition affects the physical and chemical makeup of the plastic.
How Plastic Testing Applies to Different Industries
Industrial applications require a huge number of different plastic testing procedures based on what the plastic materials in question will be used for. Professionals may need to determine their plastic’s physical and chemical characteristics, compositions, potential toxicity, resistance to temperature, pressure, and strain, durability in extreme conditions, and more.
These are just a few examples of how analysis techniques like FTIR and ESCA are practically applied in industrial contexts:
- Packaging: Many forms of packaging must be tested to ensure they don’t contain toxic materials that could contaminate whatever they’re carrying.
- Automotive: All plastic materials used in car manufacturing are subjected to a wide variety of tests to ensure they meet high industry and legal safety and durability requirements.
- Medical Devices: Plastics used in medical devices are rigorously tested to ensure they meet both general industry quality standards and, often, highly exacting requirements based on the nature of the particular device. (ex: prosthetics, pacemakers, MRIs, etc.)
- Electronics: Plastic materials used in the manufacture of electronic goods are tested to ensure they can withstand contact with sensitive electrical components without being damaged or damaging those components (ex: hard drive construction).
- Aerospace: The plastic materials used in aerospace manufacturing are exhaustively tested to determine their tensile strength, response to temperature and pressure fluctuations, fatigue resistance, and more.
- Construction: Any plastics or polymers used in construction are physically and chemically tested to ensure they’re non-toxic and sufficiently durable for use.
- Consumer Goods: Plastic used in consumer goods must be extensively physically and chemically tested to ensure it’s safe for the public to use and handle under a wide variety of circumstances.
- Environmental Conservation: Plastics used in environmental conservation efforts are especially closely tested to ensure they don’t contain toxic elements that might further contaminate the environment they’re supposed to be conserving.
- Material recycling: During and after recycling processes, plastics are physically and chemically tested to ensure they retain the right properties and have not been compromised or contaminated by other materials.
Quality Results in Plastics Analysis
If you use plastics in your products or packaging, Innovatech has a materials analysis option that will provide the insights you need to achieve the desired outcomes. Contact us for expert advice. We’ll help you determine what testing is ideal for your next project.
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