Texture analysis in action: Discover how modifying materials changes mechanical properties

Paper drinking straws are useful because they are a more environmentally friendly alternative to plastic straws. Plastic straws are not biodegradable and can take hundreds of years to break down in the environment, potentially harming wildlife and polluting oceans. In contrast, paper straws are biodegradable and can be easily disposed of in a more sustainable manner. Additionally, paper straws are a renewable resource, as they can be made from sustainably sourced materials such as bamboo.

However, paper straws are not as durable as plastic straws and can become soggy and disintegrate in a short amount of time, especially if left in a drink for too long. They are also more limited in their use – they are not suitable for all types of drinks, especially thicker liquids, like smoothies or milkshakes, which can cause the straw to soften and disintegrate quickly. 

As a result, manufacturers must conduct extensive longevity testing to ensure that paper straws retain their structural integrity and durability for the duration of time it typically takes to consume a drink.

Three-point bend testing is considered an effective method for testing the properties of drinking straws because it simulates the type of stress and strain that a straw would experience in real-world use. This test method involves placing the straw on a support and applying a load at two points, creating a bend in the middle of the straw. By measuring the force required to buckle the straw or the amount of deformation that occurs before failure, researchers can determine the straw's strength, flexibility, and overall performance. This test method can be used to evaluate both plastic and paper straws and can be customized to simulate different types of loading conditions.

During the test, the force applied, the distance moved by the probe and the time are all recorded in Exponent software. Different samples will give different load-distance responses – stronger and stiffer samples show higher forces, and tough samples show a large area under the curve corresponding to a large amount of energy required for deformation.

Recently two varieties of paper straws were tested on a TA.XTplus Texture Analyser:

sample A – plasticised white paper drinking straws

sample B – plasticised metallic paper drinking straws (with a thicker coating)

The above curve was produced from testing metallic straws
and white straws at 0, 10 and 20 minutes’ submersion time.

Properties changing with submersion time:

The following graphs were plotted in Excel to show the variation of bending force, bending distance and stiffness with submersion time in water. The points at time 0 minutes are an average of three tests.

The bending force shows that the white straws are initially stronger, but their strength drops off after a minute or two of water submersion. The initial (dry) stiffness of the metallic straws is lower, but its strength is maintained to a greater extent than the white straws. Towards the end of the submersion period, the metallic straws have a marginally higher strength.

The recyclability and biodegradability of paper drinking straws are both important considerations, so it is important for a manufacturer to find a compromise between enhanced mechanical properties (which may be the result of a thicker plastic coating) and a sample that will break down more easily.

See other examples of using a Texture Analyser for materials testing. 

See how other industry leaders use texture analysis for innovative materials testing to get ahead of their competition.

There is a Texture Analysis test for virtually any physical property. Contact Stable Micro Systems today to learn more about our full range of solutions.

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For more information on how to measure texture, please visit the Texture Analysis Properties section on our website.

The TA.XTplusC texture analyser is part of a family of texture analysis instruments and equipment from Stable Micro Systems. An extensive portfolio of specialist attachments is available to measure and analyse the textural properties of a huge range of food products. Our technical experts can also custom design instrument fixtures according to individual specifications.

No-one understands texture analysis like we do!

Get in touch to discuss your specific test requirements