EMU: Hybrid Rheometer for electrorheological, extensional, and dynamic-mechanical analyses of polymers and Rheometer for crosslinking kinetics and dynamic-mechanical characterization of elastomers

• Grant number: 23/17382-5
• Support Opportunities: Research Infrastructure Program - Small Medium Sized
• Start date: September 01, 2024
• End date: August 31, 2027
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Luiz Antonio Pessan
• Grantee: Luiz Antonio Pessan
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated researchers: Caio Gomide Otoni ; Carlos Henrique Scuracchio ; Eduardo Henrique Backes ; Juliano Marini ; Lidiane Cristina Costa ; Lucas Henrique Staffa ; Rafael Barbosa

Abstract

The equipment will be installed in a laboratory linked to the Rheology and Polymer Processing Center (NRPP) of the Department of Materials Engineering (DEMa/UFSCar). In addition to a physical space, the NRPP is an organized research group made up of professors, technicians and undergraduate and postgraduate students. It was officially established in 1996 through its recognition as a center of excellence by the National Excellence Program - PRONEX and since 05/03/2013 it has been under the responsibility of Prof. Dr. Luiz Antonio Pessan, responsible for this proposal.In this EMU, 2 types of new equipment are being requested in the EMU-FAPESP network, (1) Oscillatory Rheometer with accessories for elongational regime, electrorheology and dynamic mechanical analysis (DMA) and (2) Rubber Process Analyzer (RPA)The first is a HR 20 Discovery Hybrid Rheometer with parallel plates (TA Instruments) of high sensitivity (minimum torque of 1 nN.m). This rheometer with the requested accessories covers a wide variety of polymeric materials that can be characterized , from low to high temperatures and in different regimes, such as permanent and oscillatory, and shear and elongational flows. With the help of the elongational accessory, deeper characterizations can be carried out, for example, aimed at the development of materials for additive manufacturing, such as filaments and the simulation of the behavior of these materials during the 3D printing process, in addition to the basic understanding of the behavior of polymeric materials under elongational flow such as: blends, hydrogels and (nano)composites. Furthermore, other accessories such as electrorheology covers an area of development of materials that have unique electrical properties, such as electromagnetic shielding that can be used in military applications, as well as for the development of electronics in embedded systems such as airplanes and drones. , in addition to applications in regenerative medicine of electrically stimulated tissues, such as artificial muscles. Finally, the DMA mode allows dynamic mechanical characterization under different requests: such as frequencies, temperatures to determine viscoelastic components, degree of crosslinking, damping and thermal transitions (Tg and/or sub Tg).The second piece of equipment requested is a Rubber Process Analyzer (RPA) and is of great interest to the Materials Engineering department at the Federal University of São Carlos. In the area of polymeric materials, the history of research and extension activities in rubbers and elastomers since their pioneering creation stands out, with studies being carried out regarding formulation, processing, cross-linking and property characterization.RPA's main characteristic is the possibility of carrying out tests on elastomeric compounds in all their transformation phases until the measurement of relevant properties, such as: 1) Analyzing the behavior of the compound with variation in temperature and in the amplitude and frequency of deformation in the uncured state, mimicking the processing conditions for forming the product;2) Investigation into the molecular structure of the material, such as the relationship between rheological properties and molecular weight, chain branches, presence of gels, presence of block copolymers, etc. 3) Evaluate the curing kinetics of the compound under tension and deformation in isothermal and non-isothermal regimes. Furthermore, it is possible during curing to monitor the evolution of viscoelastic properties such as loss modules (viscous part) and storage modules (elastic part), delta tangent, among others, greatly expanding the research possibilities in models such as: foaming during vulcanization, swelling of the extrudate combined with the beginning of curing, among countless others. (AU)