Challenges in Polymer Nanocomposites Characterization

Home > Insights > Challenges in Polymer Nanocomposites Characterization

The intriguing perspective of imparting new physical properties and novel behaviors to a host polymer matrix through the simple addition of small amounts of nanoparticles is what makes polymer nanocomposites attractive.

Rather than aiming at the mere capitalization of the filler properties, the current trend is using nanoparticles as an active tool for manipulating the microstructure and, through it, the final performances of materials with phase-separated morphology, such as immiscible polymer blends.

The effects of filler adding can be a wide variety of property changes. Those are needed to be studied to predict final properties and evaluate suitability for specific purposes. Below are the properties that most nanocomposite polymers must be tested for.

There are mechanical characterization techniques useful for determining how stiff or how flexible your sample is. No matter your polymer is thermoplastic or not, dynamic mechanical analysis is a powerful tool employed to comprehend the thermal transitions of viscoelastic materials by characterizing the evolution of their macromolecular relaxation as a function of temperature and loading frequency.

The presence of nanofillers perturbs the relaxation of the polymer chains affecting the stiffness, rigidity, and energy-absorbing capability of polymeric materials. Primary glass transition (Tg) and secondary glass transition can be precisely measured from this high-sensitivity method due to the force, the heat and the frequency applied when testing. The only limitation is you cannot measure polymer in the melt state. For this, you need to go for the next technique.

The rheological characterization can monitor the processibility, flowability, and modulus of the bulk. It can also study the networks formed due to nano-sized filler in the melt system. Thus, your polymer must be melt-test under frequency and heat in a rheometer test chamber.

Some rheometers can even record the phase transition using a camera and export it as a video file. It can measure not only the complex viscosity of the melt but also other viscoelasticity values such as storage modulus and loss modulus under the given shear rate. However, the rheometer does not provide sufficient information for accurate particle morphologies of nanocomposites.

The structural features of nanocomposites can be investigated by using X-ray diffraction. The X-ray diffractometer can measure powder, thin film, nanomaterials, and solid samples.

This technique is non-destructive and fast as compared to other characterization techniques. If you have a small sample amount, the XRD analysis should be done before other time-consuming and destructive techniques.

To determine what temperature is needed to make the material melt and processable, Differential Scanning Calorimetry (DSC) can help you to find the melting temperature (Tm) and if there is no Tm due to the 100 percent amorphous structure, you can still find Tg which considered the softening point from the technique.

The degradation mechanism is one of the most important things to predict how much heat the polymer can bear under the process condition. Thermogravimetric analysis (TGA) can tell the degradation temperature (Td) of both nanomaterials added in the polymer or the matrix.

The higher the Td value, the more durable the material is. Furthermore, TGA is a useful tool to see how much additive exists in the sample. This technique can determine carbon content and oxidative stability as well.

You would never know how long the product can last when the product is being used, pressed, stretched, and bent for a long time. To study the strength of the polymer nanocomposites after applying load for billions of cycles, you need to use a fatigue tester with a very rigid load frame and friction-free linear motor to handle this job.

The technique reveals important stiffness, strength, and durability characteristics of test samples, often pushing samples to failure to determine yield strength, ultimate strength, and fatigue life.

DKSH provides a wide range of integrated and customized solutions including specialized analytical equipment and services in the fields of chemical analysis and material sciences. Reach out to us to find out how we can help with your business.

Sources:

About the Author

Chalanda is the Thermal Analysis Specialist for DKSH Management overseeing the Asia Pacific region. In her PhD thesis, she developed and characterized polymer membranes for fuel-cell application. She has over 10 years of experience in Thermal Analysis Instruments and their applications. She also supports the thermal analyzer customers in South East Asia.