In this interview, AZoMaterials speaks with Dr. Lucivan Barros, Senior Application Scientist, and Dr. Ron Rubinovitz, Senior Application Scientist, both from Thermo Fisher Scientific, about polymer upcycling. They discuss how reactive extrusion combined with FTIR microscopy provides insights into blend compatibilization and supports the creation of high-performance materials from recycled plastics.
Lucivan Barros specializes in extrusion and rheology applications, focusing on polymer processing, materials development, and structure-property relationships. In this project, he collaborated with his colleague Ron to explore the upcycling of polypropylene waste through reactive extrusion. Ron Rubinovitz, also a Senior Application Scientist at Thermo Fisher Scientific, has expertise in FTIR applications, including FTIR microscopy, FT-Raman spectroscopy, and chemometrics.
This interview summarizes the recent webinar presented by Dr. Lucivan Barros and Dr. Ron Rubinovitz - you can watch the webinar here.
Why is polymer upcycling important in addressing plastic waste challenges?
Lucivan: Plastic waste is a critical environmental issue. We produce over 400 million tons of plastic every year, and the majority ends up incinerated, landfilled, or in the environment. Upcycling provides a sustainable route to convert waste into higher-value products with better properties than the original. This contrasts with downcycling, where properties deteriorate. It’s a practical step we can take right now to mitigate long-term environmental damage.
What was the main objective of your study?
Lucivan: Our main goal was to upcycle reprocessed polypropylene (RPP) by blending it with polyamide 12 (PA12) using reactive extrusion. We aimed to evaluate how compatibilization using polypropylene grafted with maleic anhydride (PP-g-MA) improves the interface between these two immiscible polymers. To validate the compatibilization, we used FTIR microscopy to assess the mixing quality and justify improvements in mechanical properties.
How does reactive extrusion help improve compatibilization between polypropylene and polyamide 12?
Lucivan: Polypropylene and polyamide 12 are naturally incompatible. Reactive extrusion enables the formation of a diblock copolymer at the interface by reacting the maleic anhydride groups from PP-g-MA with amine end groups in PA12. This copolymer stabilizes the interface, reducing domain size and enhancing blend uniformity. The twin-screw extruder plays a crucial role by applying distributive and dispersive mixing, creating a fine and homogeneous morphology.
What did your rheological and mechanical testing reveal about the blends?
Lucivan: Rheological tests showed higher G’ values and a longer linear viscoelastic region for the reactive blend, indicating stronger interfacial adhesion. Mechanical testing demonstrated that while adding 50 % RPP initially reduced tensile strength, introducing the compatibilizer restored it to the level of neat PA12. This shows we can achieve high performance while incorporating 50 % recycled material.
How did FTIR microscopy contribute to understanding blend morphology?
Ron: FTIR microscopy allowed us to chemically map the surface of the polymer blends with high spatial resolution. We used micro ATR mapping to track the distribution of polypropylene and polyamide based on their distinct spectral features. In reactive blends, we saw a narrow variation in spectral ratios across the sample, indicating excellent mixing. Non-reactive blends showed broader variation and distinct domains. This clearly visualized the impact of compatibilization.
Why did you choose micro ATR as your FTIR approach, and what advantages did it offer?
Ron: Micro ATR was ideal because it required minimal sample preparation and allowed us to analyze thick samples with excellent spatial resolution. By embedding and polishing the pellets, we ensured stable contact with the ATR crystal. This enabled us to collect thousands of spectra across a sample and build chemical maps that revealed subtle differences in blend homogeneity.
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Can you elaborate on the value of statistical analysis of the FTIR data?
Ron: Beyond visual maps, we quantified the peak area ratios of polyamide to polypropylene and plotted distributions. The reactive blend had a tight, Gaussian-like distribution with low standard deviation, confirming uniform mixing. The non-reactive blend showed wide variability, including areas nearly pure in one polymer. These insights are essential for evaluating the effectiveness of compatibilization and process optimization.
What equipment was used for this research, and what throughput does the extrusion system offer?
Lucivan: We used the Thermo Scientific Process 11 twin-screw extruder. It features an 11 mm screw diameter and offers a maximum throughput of approximately 2.5 kg/h, depending on the material and process conditions. It’s co-rotating, ideal for compounding, and allows custom screw configurations to maximize dispersive and distributive mixing. We also used the Thermo Scientific Nicolet RaptIR + FTIR Microscope system for spectral analysis.
What are your final thoughts on the role of this combined approach in polymer research?
Lucivan: Reactive extrusion combined with FTIR microscopy provides a powerful method for polymer upcycling. It enables material scientists to develop sustainable materials with performance comparable to virgin polymers.
Ron: Agreed. FTIR microscopy enhances our ability to validate material uniformity at a chemical level. The insights it provides are critical for advancing sustainable polymer technologies.
About the Interviewees
Dr. Lucivan Barros is a Senior Application Scientist at Thermo Fisher Scientific, specializing in extrusion and rheology. He holds a PhD in Polymer Science and Engineering from the Federal University of Rio de Janeiro (UFRJ), Brazil. His work focuses on sustainable polymer processing, advanced materials development, and understanding structure-property relationships. With extensive experience in reactive extrusion and blending, Lucivan is passionate about applying innovative processing techniques to real-world environmental challenges.
Dr. Ron Rubinovitz is a Senior Application Scientist at Thermo Fisher Scientific, 
where he focuses on FTIR applications, microscopy, and chemometrics. He received his PhD in Physical Chemistry from the University of Pennsylvania, with research focused on molecular spectroscopy using FTIR. Ron has over two decades of experience applying vibrational spectroscopy to material science problems and is an expert in micro-ATR and imaging techniques for polymer characterization.
This information has been sourced, reviewed and adapted from materials provided by Thermo Fisher Scientific - Vibrational Spectroscopy.
For more information on this source, please visit Thermo Fisher Scientific - Vibrational Spectroscopy.
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