Rheology is Maza: Unveiling the Secrets of Flowing Rangoli Colors

Part of our Rheology is Fun series! This month, we’re celebrating Diwali so Rheology is Maza – fun in Hindi.

Behbood Abedi
October 28, 2024

Powders are a big part of everyday life, from baking and laundry to cosmetics and pharmaceuticals. Understanding powder rheology—how powders flow and deform—is crucial for optimizing their use in various applications. This knowledge helps industries maintain consistency and product quality.

The Great Powder Showdown: Flow Adventures!

First up, we tested how well these powders could be compressed (see Fig. 1). It was fascinating to watch the blue and red powders compress almost twice as much as the white and yellow ones. These differences were noticeable when we pressed the powder on our rangoli designs, too. The green powder? It landed somewhere in between, not wanting to pick sides.

Next, we measured the flow function of these powders (See Fig. 2). The flow function reveals how easily a powder can flow and be processed under relatively high stress. Here’s what we discovered:

• White and yellow Powders: These powders are right on the edge of easy and free-flowing. They will flow smoothly from the squeeze bottle without any hiccups.
• Blue and Red Powders: These powders are a bit more stubborn. Their flow function is on the border of easy-flowing and cohesive flow, meaning they’ll have a tougher time flowing from the squeeze bottle.

We also looked at the unconfined yield strength of these powders. This tells us how well the powders can resist forces like the wind. The blue and red powders showed twice the yield strength of the white and yellow ones. So, if you’re working on your rangoli outside in a windy area and pressing your powders down onto your design, the blue and red ones will hold their ground better.

From our SEM images (Fig. 3), we saw that coloring process with pigments not only altered the appearance of the blue powder but also modified its physical properties. The blue powder is made up of smaller particles than the white and has smoother, rounder surfaces. This change wasn’t just cosmetic—these tiny particles, with higher surface area to volume ratio, significantly boosted the blue powder’s compressibility and cohesion, which we saw earlier in Figures 1 and 2. It’s amazing how a bit of pigment, some shaking, and drying can dramatically change the rheology of a powder!

In summary, our curiosity about the rheology of rangoli powders revealed some cool insights into how rangoli powders behave under distinct flow conditions. Whether you’re looking for easy flow or better resistance to wind, now you know which powders to pick.

The Curious Case of Turmeric and Green Powder: A Rangoli Revelation

Sometimes, very different powders can surprise us with similar traits. Take turmeric, for example – a popular choice for rangoli. Despite looking finer and lighter than the rangoli powders we used, turmeric interestingly shares the same flow function value as the green powder (See Fig. 4).

Why, you ask? Well, turmeric can be compressed twice as much as the green powder (see Fig. 5), likely boosting its cohesion under higher stress. When we examined the powders using SEM (see Fig. 6), we noticed that both powders had a lot of small debris, which can affect their cohesion and flowability when compacted.

However, when it comes to unconfined and confined flow energy—where the powders aren’t under high stress – the green powder’s flow energy is significantly higher than turmeric’s (See Fig. 7). This could be due to several factors, including the rounder surface of turmeric compared to the rougher surface of the green powder.

So, while turmeric and green powder may look and feel different, they can behave quite similarly under certain conditions. When you flow these two powders from a squeeze bottle, you experience the same flowability. However, when you spread them on the surface to create designs with your brush or finger, turmeric flows much more easily. It’s a fascinating reminder that appearances can be deceiving, especially in the world of powders!

As we dive into the festive spirit of Diwali, the art of rangoli brings a playful twist to powder rheology. Whether it’s the smooth flow of white powder or the stubbornness of blue powder, each has its unique charm and challenges.

However, in industrial settings, these properties are more than just fascinating – they’re critical. So, whether you’re spreading turmeric for a beautiful rangoli or ensuring the consistency of a pharmaceutical product, understanding powder rheology is key. It’s a fascinating blend of art and science that keeps both our celebrations and industries running smoothly.

Linear Viscoelastic Region: Why It’s Crucial in Materials Testing

Keith Coasey | Morgan Ulrich
September 9, 2024

Our world is brimming with viscoelastic materials: The dough you knead before baking a fresh loaf, the Silly Putty your toddler slaps against the wall, the rubber gaskets that create an airtight seal on an airplane door. Testing those materials by applying controlled deformations (strains) or forces (stresses) at various timescales, temperatures, and/or humidities allows for the optimization of properties and ensures durability and safety. Only through specialized tools in a lab setting can researchers thoroughly characterize (and thus predict in the real world) an essential material property: the linear viscoelastic region.

What is the Linear Viscoelastic Region (LVR)?

In scientific terms, it’s the linear relationship between the complex stress put on a material and the overall magnitude of deformation (strain), which remains linear at relatively low strains. At strains/stresses that extent beyond the LVR, the relationship becomes nonlinear, with the stress typically increasing less with additional strain, indicative of the onset of network failure. A complex liquid will have a larger LVR than a brittle solid which typically fails at lower strains. In simpler terms, it’s the range in which a material predictably reacts (and can return to its original form) under different amounts of strain/stress.

Think of a rubber band. Pull it gently before letting go, and it will return to its original, relaxed state. Stretch it more and more, and it will still return to form – up to a point. Eventually, you might see a slight tear or a color change when it relaxes. Pull hard enough, and the band will snap altogether. Once you have materially changed the band’s properties, you’ve left the linear viscoelastic region and entered its “critical strain” — the threshold at which the material’s molecular structure fundamentally changes.

Characteristics of the Linear Viscoelastic Region

Determining the LVR should be one of the first steps when studying or testing viscoelastic materials. The LVR is a function of temperature, humidity, and the rate of the deformation. Generally, the LVR increases with increasing temperature, so once the LVR is characterized at a single deformation rate at a specific temperature, the temperature can be increased without exceeding the critical strain.

There are two ways to consider the LVR and its relation to strain/stress. First, when a material is within the LVR, the force (stress) required to deform the material increases or decreases in a fashion relative to the extent deformation. Once stretched beyond the critical deformation, it requires increasingly less additional force to achieve incrementally higher deformations. In another case, if considering hanging weights from a spring or rubber band, one is applying stress (force) in the form of weight in order to deform the sample. Within the LVR, if the weight is incrementally increased, the spring or rubber band will elongate in proportion to the weight. Once beyond the critical strain (which corresponds to a critical stress), the spring or rubber band starts to elongate more and more with each additional unit of stress/weight.

Figure 1: Stress vs strain in an oscillation strain sweep experiment on polystyrene at 250 °C and 1 Hz. The critical strain is marked on the plot.

Say you’re developing a delicious new yogurt (itself, a viscoelastic material). But you know that the trucks headed to deliver that yogurt will traverse bumpy roads. You’ll need to test how that yogurt reacts under all of that shaking (gravitational forces). If the network structure of the yogurt is too weak, in the sense that the end of the LVR corresponds to low strains or stresses relative to those experienced in the truck, then the yogurt network structure will be disrupted. Rather than having a continuous creamy texture, the yogurt can be broken up into separate chunks, sometimes with separated liquid, and in essence more akin to the texture of cottage cheese than yogurt.

Understanding the characteristics within the yogurt’s LVR helps not only formulate a yogurt that is mechanically robust enough for transport, but also still has a texture/viscoelasticity that is favorable to eat. Eating creates its own characteristic stresses and deformations in the mouth, which need to be accounted for (Who would want to eat chewy yogurt?).

Why is the Linear Viscoelastic Region Crucial in Materials Testing?

Think of the LVR as a set of guardrails. When you use too much stress, you’ll cross the critical strain threshold and irrevocably change its structure. Add too little stress, though, and you end up with noisy data. Staying within the LVR during dynamic (oscillatory) mechanical testing allows for the ideal probing of the sample in a quasi-equilibrium state; where its mechanical structure can be probed at a variety of conditions such as at various temperatures (mimicking real-world conditions), without disrupting destroying the sample structure mechanically and with excellent data resolution/reproducibility.

The LVR is also essential in understanding the complete rheological characteristics of a material (how it flows through the environment around it). Practically, this helps manufacturers and product researchers choose, replace, or refine the materials they need before full-scale production begins.

How to Determine a Material’s Linear Viscoelastic Region

Three variables will change the LVR of any material: Temperature, humidity, and the rate of deformation (frequency). A piece of rubber pulled in sub-freezing weather 1,000 times will react differently than one pulled twice on a humid August afternoon.

Because our environment (and how we use materials) constantly changes, there are two accurate methods to determine LVR.

1. Experimental: Specialized lab equipment like a dynamic mechanical analyzer (DMA) which is primarily for solids or a rheometer which primarily deals with liquids, provide precise data to determine the LVR. These instruments can change temperature, humidity, and stress levels—efficiently repeating a cycle thousands of times.
2. Analytical: Because the LVR is, by its nature, linear, you can accurately model it using math (software like TA Instrument’s TRIOS, makes this process easier). Leverage this information back in the lab, and you often don’t need to discern the exact critical strain of a material. Once you know the LVR, you can stick within that threshold. Conversely, the analytical approach models the minuscule stress and strain data at the range’s bottom end, meaning you don’t need to waste lab time gathering that data.

LVR in the Real World: Top Industries & Applications

When you’re on the 60th floor of a skyscraper or swallowing a Vitamin D supplement, you rely on the predictable viscoelasticity of materials all around (and inside!) you. That’s why you will find LVR testing is crucial in a vast array of industries, including:

Polymer and Plastics: Both materials are in products we use every day (probably even every hour). Knowing when and how they fail–and, for sustainability purposes, how they will react when they’re recycled–requires determining their LVR in a lab setting. With knowledge of the LVR, temperature ramps can be performed on polymers, effectively characterizing glass transitions (softening points), mechanically properties through thermal transitions (melting, crystallization), and properties such as crosslink density (essential for cured materials and rubbers – UV curable materials, epoxy, etc.)

Pharmaceuticals and Food: Your body itself is a viscoelastic structure, and so are the methods and materials used to keep it at its healthiest. From the capsule of a pill to plant oil emulsions that could replace saturated fat–understanding a material’s properties makes for an overall better quality of life. The LVR can give knowledge of the yield stress of a therapeutic cream and therefore its shelf life, or similarly the yield stress of a yogurt.

Construction: Cement is a fantastic example of a viscoelastic material that changes states due to time and temperature. The building you are in – right now – has not collapsed because researchers know how durable and stable its materials are over time and under stress. The LVR can be an effective characterization tool for paints which help maximize building material lifetime (critical for combating mold, UV, humidity, corrosion), with the LVR again characterizing shelf stability through the yield stress. The LVR can also help characterize the durability of composite materials commonly used in flooring, ceilings, and benchtops.

Conclusion: Materials Innovation Starts in the Lab

The world simply works better because we understand (and can innovate) viscoelastic materials: From the soap that morphs into foam when pumped from a bottle to the way a vaccine exits a syringe. These advances, however trivial or monumental, only happen because of research in the lab. Just like you can’t sprint before learning to crawl, you can’t make your product safer, healthier, lighter, cheaper, or more durable without understanding its linear viscoelastic region. If viscoelastic materials are building blocks to a better world, then the LVR is a building block to creating better versions of those materials. Contact TA Instruments for expert guidance in testing and optimizing your materials.

Overcoming Composites R&D Challenges with Material Analysis

Julienne Regele | Morgan Ulrich
July 29, 2024

Composite Applications and Industry Drivers

R&D Challenges

Properties to Measure for Success Against R&D Challenges

Key Insights from TA Instruments

References:

1. Markets and Markets. [Online] Composites Market. Available at: https://www.marketsandmarkets.com/Market-Reports/composite-market-200051282.html#:~:text=The%20global%20composites%20market%20size,USD%20108.8%20billion%20in%202023 (Accessed on 10 July 2024).
2. Mrazova, M. (2013). Advanced composite materials of the future in aerospace industry. INCAS BULLETIN. doi.org/10.13111/2066-8201.2013.5.3.14
3. Khan, F., et al. (2024). Advances of composite materials in automobile applications – A review. Journal of Engineering Research. doi.org/10.1016/j.jer.2024.02.017
4. Adekunle, P.A., et al. (2024). Benefits of Integrating Advanced Composite Materials Into Modular Construction For Enhanced Structural Performance. Transforming Construction with Off-site Methods and Technologies (TCOT) Conference: Designing Tomorrow’s Construction, Today.
5. Ramesh, M., et al. (2022). Influence of filler material on properties of fiber-reinforced polymer composites: A review. e-Polymers. doi.org/10.1515/epoly-2022-0080
6. Thomas, S. (2021). Green Composites: Materials Horizons: From Nature to Nanomaterials. Springer Nature. ISBN: 9789811596438
7. Tech Briefs. (2018). [Online] Pros & Cons of Advanced Lightweighting Materials. Available at: https://www.techbriefs.com/component/content/article/28549-pros-cons-of-advanced-lightweighting-materials (Accessed on 10 July 2024).
8. Zindani, D., et al. (2019). An insight into additive manufacturing of fiber reinforced polymer composite. International Journal of Lightweight Materials and Manufacture. doi.org/10.1016/j.ijlmm.2019.08.004
9. Hagnell, M.K., et al. (2015). A composite cost model for the aeronautical industry: Methodology and case study. Composites Part B: Engineering. doi.org/10.1016/j.compositesb.2015.04.043
10. Miller, S.G., et al. (2023). Manufacturing and Mechanical Testing of TC1225/LM-PAEK and TC1200/PEEK Thermoplastic Composite Panels. NASA. Available at: https://ntrs.nasa.gov/api/citations/20220015690/downloads/TM-20220015690.pdf
11. Shnawa, H.A. (2022). Studies on thermal properties and curing kinetics of talc-filled epoxy resin composite using differential scanning calorimetry. Polymer Bulletin. doi.org/10.1007/s00289-021-04012-1
12. Gotro, J. (2016). [Online] UV Curing of Thermosets Part 14: Using UV DSC to Monitor Curing – 1. Polymer Innovation Blog. Available at: https://polymerinnovationblog.com/uv-curing-thermosets-part-14-using-uv-dsc-monitor-curing-1/ (Accessed on 11 July 2024).
13. Koutsomichalis, A., et al. (2021). Mechanical Testing and Modeling of the Time–Temperature Superposition Response in Hybrid Fiber Reinforced Composites. Polymers. doi.org/10.3390/polym13071178
14. Saba, N., et al. (2018). A review on thermomechanical properties of polymers and fibers reinforced polymer composites. Journal of Industrial and Engineering Chemistry. doi.org/10.1016/j.jiec.2018.06.018

Rheology Theory and Applications

Sarah Cotts | Kimberly Dennis
June 24, 2024

Will my paint coat the wall or drip off? Will my topical pharmaceutical spread on skin or form clumps? Rheology answers vital questions to inform how we create and interact with materials on a daily basis.

What is rheology?

Rheology is the study of the deformation and flow of matter and can provide a foundational understanding of material behavior. The relationship between stress and deformation is a property of the material, so rheology helps link the properties of a sample to its overall performance. A rheometer applies stress or strain to a sample and the resulting deformation or stress is measured.

Rheology investigates materials in terms of deformation and flow. Deformation is how much a material moves when a force is applied. For example, a stress ball temporarily changes shape when you squeeze it.

Flow is the measurement of a fluid’s movement from one point to another. The opposition to flow in a material is called viscosity, with highly viscous materials having lower degrees of flow. Honey is more viscous than water and thus flows slower at room temperature.

Viscous and Elastic Material Behaviors

All materials exist on a spectrum between two bounds: viscous liquids, like water, and elastic solids, like metal. Most materials fall somewhere in the middle and are viscoelastic, exhibiting both viscous and elastic properties. For example, silly putty can be rolled into a ball and bounced over short times, but over long times, it flows and flattens out.

Viscous liquids are used in dashpots, which are a kind of damper that uses the viscous liquid to dissipate a plunger’s energy into heat. Elastic solids are like springs that recover from deformation. Viscoelastic materials fall somewhere in the middle, illustrated by a combination of both models.

Importance of Rheological Measurements

Since a material’s molecular structure affects its rheological properties, rheology is often used for quantitative and qualitative molecular analysis. This rheological data can provide material insights and inform structural design changes.

Rheology is frequently used to evaluate processing conditions and product performance since it can be used to link final properties back to the material’s underlying structure. For example, how do additives affect processing a polymer melt? And will that same polymer maintain its shape when it is molded into a car component? Rheology thus supports successful material design and quality control testing.

Newtonian and Non-Newtonian Fluids

Within viscous fluids, there is an important distinction based on their viscosity. A Newtonian fluid’s viscosity is independent of shear rate or shear stress. Viscosity measurements as a function of shear rate or shear stress show a flat line like in the figure below, meaning their viscosity is constant. Examples of Newtonian fluids include water, ethanol, and cooking oil.

Non-Newtonian fluids exhibit a viscosity change with shear rate and shear stress. If viscosity increases, the fluid is shear thickening, like the materials measured on the plot below. For example, a highly concentrated cornstarch slurry is shear thickening and becomes more viscous as you stir it.

If viscosity decreases with shear rate and shear stress, the fluid is shear thinning, shown in the plots below. Hand soap is shear thinning – it becomes less viscous as you apply stress by rubbing it between your hands.

Non-Newtonian fluids often have viscosity properties that are time-dependent. In these cases, the shear rate or stress is kept constant and time is the variable instead. If the viscosity increases over time, the material is known as rheopectic, like the green line below. If it decreases with time, the material is known as thixotropic, like the blue line below. Printer ink is rheopectic, and shaving cream is thixotropic.

Overall, rheology provides a way to characterize material deformation and flow based on its response to applied stress. Rheometers apply and measure wide ranges of stress, strain, and strain rate, while simultaneously controlling the material’s environment. Rheology thus offers important information for successful material processing and optimal end-use performance.

Contact TA Instruments for an expert opinion on how rheology can facilitate your material design, analysis, and manufacturing.

Characterization Considerations when Sourcing PCR

Julienne Regele | Morgan Ulrich
May 8, 2023

Against the backdrop of a plastic waste crisis, the global demand for plastic is set to quadruple by 2060.¹ This has driven a shift toward sustainability and away from linear use models of plastic production. Post-consumer resin (PCR) has emerged as a key player in circular economy initiatives, though ensuring the quality and performance of PCR requires several characterization considerations.

Understanding PCR

PCR represents a group of plastics that have fulfilled their intended purpose and undergone a process of collection, cleaning, and re-pelletization for reuse. Reincorporating PCR into new products and packaging is crucial for circularity. By closing the loop of plastic consumption, the industry is able to reduce the demand for virgin resources and minimize the environmental impact caused by pollution and extracting natural resources.
Similar though distinct materials include post-industrial resin (PIR) and rework. The former consists of resins that have undergone conversion into a product deemed either out-of-specification or unsalable and, therefore, has never reached the end customer or consumer. Rework relates to waste generated within a manufacturing process that is subsequently reused within the same process instead of being sold to another manufacturer.

Material Characterization Considerations

Material Purity

In contrast to virgin resins, PCR feedstocks exhibit greater complexity and substantial variability due to their diverse origin. Despite advancements in sorting technology, this diverse origin can present significant challenges for processing engineers, such as the risk of contamination.

Differential scanning calorimetry (DSC) can play a role in testing the purity of PCR by scanning for unidentified peaks within the material. These peaks can be compared to reference polymers, enabling the determination of the composition and purity of the PCR sample. This method facilitates the detection of contaminants or impurities, supporting batch-to-batch quality control efforts and ensuring the integrity of the recycled material.²

Material Behavior

As mentioned above, PCR obtained from various sources can exhibit heterogeneity. This can extend beyond impurities to variations in molecular weight and molecular weight distribution, leading to inconsistencies in crystallinity, crystal melting behavior, and resin melt viscosity across different batches.²

DSC
DSC enables precise assessments of PCRs’ crystallinity and crystal melts, which is necessary information for determining the appropriate processing temperature and cooling rates during manufacturing processes such as extrusion or injection molding.

By reporting on glass transition temperature (Tg), DSC provides essential data for understanding the material’s mechanical and thermal behavior during processing and in the final product. By correlating crystallinity data from DSC with Tg, manufacturers can optimize processing parameters to ensure efficient production and the desired material properties in PCR-based products. Additionally, Waters | TA Instruments’ DSC has the capability to implement Guided Methods, which walks new users through experiments like this with step by step instructions.

For those handling multiple samples, TA Instruments’ Discovery X3 DSC is ideal. This model incorporates a multi-sample cell capable of providing high-quality heat flow data for three samples concurrently.^2,3

Rheometry
Rotational rheometry can be used to obtain information on how the molecular structure of PCR feedstocks impacts processing characteristics. Through measuring melt viscosity over time and temperature, rheological analysis facilitates the evaluation of thermal stability at processing temperatures and the optimization of processing conditions.²

The ARES-G2 and Discovery Hybrid Rheometers (DHR) from TA Instruments offer advanced capabilities for assessing the rheology of PCR polymers. The ARES-G2 provides unparalleled data accuracy through separate motor and transducer technology (SMT) and precise temperature control, optimizing material processability and defining critical quality attributes (CQAs).

The DHR, on the other hand, offers unmatched performance, ease of use, and versatility.Regardless of the desired stress, shearing or oscillating force, or deformation, the DHR is a keystone instrument for top laboratories worldwide. With intuitive designs and an integrated Dynamic Mechanical Analysis (DMA) mode, these rheometers support advancements in materials science and product development.^4,5

Material Performance

The variety of plastics present in PCR poses significant challenges for secondhand processing in value-added applications. Variety introduces incompatibility of blends, leading to undesirable mechanical properties and impacting the rheology and dynamics of the plastic. These factors are crucial in determining the material’s viability for use in manufacturing processes and its suitability for specific applications. To enhance compatibility and stabilize the morphology of PCR, compatibilizers like block co-polymers, carbon nanotubes, and silica nanoparticles are added.⁶

Throughout their lifespan and reprocessing cycles, recycled plastics also experience degradation, characterized by a reduction in molecular length.⁷ Accordingly, there is typically a trade-off that needs to be assessed when incorporating recycled content into virgin plastics.

Dynamic Mechanical Analysis (DMA) proves highly effective in evaluating the thermal and mechanical attributes of solid polymer samples. This technique facilitates the characterization of a material’s viscoelastic properties, including storage modulus, loss modulus, and tan δ, aiding in evaluating the ultimate performance characteristics of solid products and their correlation with material chemistry. DMA also stands out as one of the most sensitive methods for determining a material’s glass transition temperature, valuable for quality control, development, guiding processing conditions, and diagnosing product failures.⁸

Mechanical testing of polymers in end applications, including test techniques like fatigue, creep, and bending, can be performed using TA Instruments’ suite of ElectroForce instruments. These machines are specifically crafted for ultra-durable and high-precision testing to provide outstanding force capacity, speed, precision, and accuracy.⁹

Building a Greener Future with PCR

The utilization of PCR underscores a pivotal paradigm shift towards sustainable plastic development. As the imperative to combat plastic waste intensifies, embracing PCR emerges as a pragmatic solution for realizing a greener future. Through the application of proper characterization techniques such as DSC, rheometers, and mechanical testing, stakeholders can navigate the complexities of material selection and uphold stringent quality standards, thereby advancing the integration of PCR into mainstream manufacturing processes.

Leveraging TA Instruments’ cutting-edge products tailored to the unique demands of PCR characterization, the industry can catalyze transformative change and chart a course toward a more sustainable and resilient future.

To learn more about these instruments, contact TA Instruments’ material characterization experts today.

References and Further Reading

1. Smith, P., et al. (2024). A data-driven analysis of HDPE post-consumer recyclate for sustainable bottle packaging. Resources, Conservation & Recycling. doi.org/10.1016/j.resconrec.2024.107538
2. TA Instruments. [Online] RH122: Using Rheology and Thermal Analysis to Help Optimize Processing Conditions of Recycled PET. Available at: https://www.tainstruments.com/pdf/literature/RH122.pdf
3. TA Instruments. [Online] Multi-Sample X3 DSC. Available at: https://www.tainstruments.com/x3-dsc/ (Accessed on 29 March 2024).
4. TA Instruments. [Online] ARES-G2. Available at: https://www.tainstruments.com/ares-g2/ (Accessed on 29 March 2024).
5. TA Instruments. [Online] Discovery Hybrid Rheometers. Available at: https://www.tainstruments.com/products/rheology/discovery-hybrid-rheometers/ (Accessed on 29 March 2024).
6. Muzata, T.S., et al. (2024). Challenges in the mechanical recycling and upcycling of mixed postconsumer recovered plastics (PCR): A review. Current Research in Green and Sustainable Chemistry. doi.org/10.1016/j.crgsc.2024.100407
7. Hinczica, J., et al. (2022). Influence of Recyclates on Mechanical Properties and Lifetime Performance of Polypropylene Materials. Procedia Structural Integrity. doi.org/10.1016/j.prostr.2022.12.017
8. TA Instruments. [Online] Introduction to Dynamic Mechanical Analysis and its Application to Testing of Polymer Solids. Available at: https://www.tainstruments.com/applications-notes/introduction-to-dynamic-mechanical-analysis-and-its-application-to-testing-of-polymer-solids/ (Accessed on 29 March 2024).
9. TA Instruments. [Online] ElectroForce Mechanical Test Instruments. Available at: https://www.tainstruments.com/products/electroforce-mechanical-testers/ (Accessed on 29 March 2024).

同步应用流变和阻抗测量对电池浆料进行评估

Morgan Ulrich | Hang Lau | Sarah Cotts
2024 年 3 月 18 日