Low field NMR for analysis of rubbery polymers
type: CreativeWork
description: The goal of this work is to investigate the molecular dynamics as well as the composition and the structures of different types of industrial polymers such as thermoplastic polyurethanes (TPU) and filled raw EPDM samples. The NMR measurements were restricted to transverse relaxation of the magnetization and DQ NMR experiments, done on a low field spectrometer (0.5 T) at a proton Larmor frequency of 20 MHz. The measurement temperatures were varied, depending on the glass transition temperature of the investigated materials. A measurement temperature 100° C above the glass transition temperature provides a high molecular mobility and an enhanced contrast in the NMR signal. Moreover, thermal (DSC) and mechanical (rebound resilience, hardness and tensile testing) tests have been done on the TPU materials, and their macroscopic properties have been determined.The purpose of investigating the TPU samples is a better characterization of these materials by combining a set of measurements, in particular differential scanning calorimetery, rebound resilience, hardness, tensile testing, and NMR techniques. The mechanical and the thermal properties of thermoplastic polyurethanes, as well as their chain dynamics determined by NMR are influenced by the number average molecular weight of the segments, the type and the amount of the hard and soft segments, the interaction between these two phases and by the capacity of soft segments to crystallize. The good correlation between the macroscopic properties as determined by classical methods and the microscopic properties determined by NMR recommends low-field NMR as a potential method for quality control, with the particular of being fast, inexpensive and partially non-destructive.The influence of the filler amount and activity on the unvulcanized EPDM polymer matrices was investigated via transverse relaxation NMR experiments. The results were interpreted using both the Sotta, Fülber, Demco, Blümich, Spiess and the Gotlieb-Fedotov-Sc…
abstract: The goal of this work is to investigate the molecular dynamics as well as the composition and the structures of different types of industrial polymers such as thermoplastic polyurethanes (TPU) and filled raw EPDM samples. The NMR measurements were restricted to transverse relaxation of the magnetization and DQ NMR experiments, done on a low field spectrometer (0.5 T) at a proton Larmor frequency of 20 MHz. The measurement temperatures were varied, depending on the glass transition temperature of the investigated materials. A measurement temperature 100° C above the glass transition temperature provides a high molecular mobility and an enhanced contrast in the NMR signal. Moreover, thermal (DSC) and mechanical (rebound resilience, hardness and tensile testing) tests have been done on the TPU materials, and their macroscopic properties have been determined.The purpose of investigating the TPU samples is a better characterization of these materials by combining a set of measurements, in particular differential scanning calorimetery, rebound resilience, hardness, tensile testing, and NMR techniques. The mechanical and the thermal properties of thermoplastic polyurethanes, as well as their chain dynamics determined by NMR are influenced by the number average molecular weight of the segments, the type and the amount of the hard and soft segments, the interaction between these two phases and by the capacity of soft segments to crystallize. The good correlation between the macroscopic properties as determined by classical methods and the microscopic properties determined by NMR recommends low-field NMR as a potential method for quality control, with the particular of being fast, inexpensive and partially non-destructive.The influence of the filler amount and activity on the unvulcanized EPDM polymer matrices was investigated via transverse relaxation NMR experiments. The results were interpreted using both the Sotta, Fülber, Demco, Blümich, Spiess and the Gotlieb-Fedotov-Sc…
author: Voda, Alexandra Elena
language: eng
keywords: info:eu-repo/classification/ddc/660, Technische Chemie, Mehrquanten-NMR-Spektroskopie, Kernspinrelaxation, thermoplastischer Urethane, gefüllter EPDM-Werkstoffe, DSC, Rückprallelastizität, Zugversuche, thermoplastic polyurethane, filled EPDM rubber, rebound resilience, tensile tests
date published: 2006
date modified: 2026-07-30T19:43:02Z
provider: RWTH Aachen University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Publikationsserver der RWTH Aachen University