Estimation of the Selective Localization of Organometallics in PE/PP/PET PCR Blends via Quantitative Nanomechanics Mapping

• Grant number: 25/24490-4
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: January 30, 2026
• End date: April 29, 2026
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Lucas Henrique Staffa
• Grantee: Marina Eichemberger Martinez Mergulhão
• Supervisor: Joao Paulo Cosas Fernandes
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Institution abroad: Centre De Recherches Sur Les Macromolécules Végétales, France
• Associated to the scholarship: 25/04198-7 - Compatibilization and Regeneration of PCR PE, PP, and PET Blends through the Addition of Organometallics, BP.MS

Abstract

Mechanical recycling of polymers is a route to enable circularity. However, its rates remain low compared to the total volume produced. In this post-consumer material recycling scenario, the challenge is that the input material may be degraded, and sorting the specified polymers is complex. The treatment of physically mixed plastics and other multi-resin polymeric products requires solutions to overcome the inherent incompatibility and immiscibility of the multicomponent recycled material. Therefore, new compatibilization strategies can be established. The objective is to investigate specialized additives that functionalize one (or more) phase(s) of the mixture with organometallic monolayers, increasing adhesion between phases while simultaneously supporting a "repolymerization" bed through the catalytic action on the immiscible polymer phases. Thus, post-consumer recycled (PCR) PE, PP, and PET blends were produced to simulate recycling via co-rotating twin-screw extrusion and thermokinetic mixer in the presence of a neoalkoxy titanate-based organometallic compound. Partial results, summarized in the submitted partial report, have already demonstrated promising improvements in rheology, in which PET PCR processed via extrusion showed a mitigation in the loss of viscosity when processed with the titanate additive, when compared to the unmodified sample. Similar results were observed with PP when processed in the thermokinetic mixer. Morphologies also indicate a reduction in the droplet radius. Therefore, AFM nanomechanical analysis will be performed to understand the preferential interactions of the organometallic with the blend phases and to verify the mechanical properties enhancements resulting from the possible chain re-formation of the polymer phases through the catalytic action of the organometallic. This proposal is supported not only by the expertise of Dr. Cosas, CNRS researcher, in this field, but also by the infrastructure available at CERMAV/CNRS, as well as by the student's clear qualification to take advantage of the opportunity abroad for theoretical advancement, data collection and processing, and partial development of the experimental component of this master's project. The intentions stated herein are part of the master's fellowship of the student, funded by FAPESP (grant 2025/04198-7), and are also included within the broader scope of a Regular Research Grant (grant 2023/05519-6). The goal is to enhance the usefulness of multicomponent recycled products by adding an organometallic compound, enabling new alternatives through in situ macromolecular regeneration of PP,