Qualification of automated low-field NMR relaxometry for quality control of polymers in a production setting

Abstract

Implementation of a low field time-domain NMR scanner as a diagnostic tool in the production of new polymer components is described in the context of qualification of a new QA/QC device. A study to determine the optimal experimental parameters was performed and a robotic autosampler was built to enable scanning of multiple pads.Relationships between T 2 values and physical properties of DC745 slabs were investigated, and the appropriate sampling parameters for the production setting were determined. Two versions of a robotic autosampler were built, and for the component described here a fourth radial axis was required in addition to traditional X, Y, and Z movement to eliminate the large variability in T 2 due to inconsistent sample coverage caused by complex rib geometry of the component. Data show that with appropriate choice of experimental conditions of the NMR detector and the detection geometry of the 1 robotic autosampler, sufficient resolution of variations in crosslink density on the millimeter scale could be determined. All data to date demonstrates that low-field NMR devices are a feasible tool for use in production settings for non-destructive quality control of polymer components.

A method based on time domain nuclear magnetic resonance for the forensic differentiation of latex gloves

“…stiff or hard regions, and soft View Article Online components of the sample all influence the shape of the relaxation signal, and thus the value of T 2 . 24,25 Also in the case of T 2 , the error was evaluated by performing replicated measurements on different days. The Ansell glove was analyzed nine times, its CPMG curve was acquired and fitted, and T 2 was computed.…”

Evaluation of Automated Low-Field NMR Relaxometry For Analysis of Polymers

“…A new test method has been developed and validated based on a unique system design using an NMR coupled with automated data collection 1 . A prototype system has been installed at the Kansas City Plant to evaluate its use for surveillance testing.…”

“…The magnet of the NMR ProFiler, is mounted to a modified commercial Autosampler (produced by Duratech Inc., Waynesboro, VA) and controlled via an attached PC for automated NMR measurements (Figure 1). Previous work focused on rotating OPPs beneath a stationary ProFiler, and also on determining the proper orientation alignment of the magnet over the OPP during motion control by the Autosampler 1 . Subsequent screening tests identified anomalous random noise in measurements, variance in curve fits to determine T 2 , and possible measurement error caused by nearby metal components adjacent to arbitrarily assigned measurement locations within the chamber ( Figure 2).…”

Evaluation Of Automated Low-Field Nuclear Magnetic Resonance (NMR) Relaxometry For Analysis Of Silicone Polymers

“…A new test method has been developed and validated based on a unique system design using static, uniaxial NMR relaxometry coupled with automated data collection [2]. A prototype system has been installed at KCP to evaluate its use for surveillance testing.…”