Characterization of local deformation in filled-silicone elastomers subject to high strain – NMR MOUSE and Magnetic Resonance Imaging as a diagnostic tool for detection of inhomogeneities

• Published in: Polymer degradation and stability Vol. 91; no. 8; pp. 1701 - 1710
• Main Authors: Herberg, Julie L., Chinn, Sarah C., Sawvel, April M., Gjersing, Erica, Maxwell, Robert S.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.08.2006; Elsevier Science
• Subjects: Applied sciences; Composites; DC745; Exact sciences and technology; Forms of application and semi-finished materials; MRI; NMR; NMR MOUSE; Polymer degradation; Polymer industry, paints, wood; T2 measurements; Technology of polymers; NMR MOUSE; NMR; DC745; Polymer degradation; MRI; T 2 measurements; High strain; Molecular structure; Crosslink density; Dispersion reinforced material; Compressive strength; NMR spectrometry; Composite material; Heterogeneity; Spin spin relaxation; Investigation method; Vulcanizate; Radiochemical degradation; Silicone elastomer; T2 measurements; Stress strain relation; Mechanical properties; Experimental study; Nuclear magnetic resonance imaging; Gamma radiation; Manufacturing defect; Artificial ageing
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/j.polymdegradstab.2005.12.006

Magnetic Resonance Imaging (MRI) and unilateral Nuclear Magnetic Resonance (NMR) relaxometry with the NMR MOUSE (MObile Universal Surface Explorer) have been used to characterize local permanent deformation in silicone parts subject to high compressive strain. Samples returned from field service have been characterized by areas of high compression set. Materials excised from these damaged sections have been shown to be clearly distinguishable from undeformed material from the same part and from pristine material by NMR spin-echo, NMR MOUSE and MRI protocols. The results of these studies have been interpreted in the context of studies of model materials of varying crosslink density. The areas of local deformation have been characterized by a reduction in the residual dipolar coupling, which is proportional to the crosslink density and in the non-network sol fraction. These differences were likely to be present in these polymers at the time of production due to inefficient mixing. Additionally, both T 2 weighted Single Point Imaging (SPI) and T 2 weighted MRI experiments have been used to map out the location of different crosslink densities, ultimately determining the quality or homogeneity in silicone components.