2. Materials applications

2.1 Structure of polymers and composites

Due to the difficulties of using NMRI on rigid solids, most applications for polymers have been directed towards elastomers or inflated structures . Work on pneumatic materials is a good example. Elastomers typically have linewidths of 500 to 1,000 Hz and T ₂ values of 0.1 to 2 ms, too small for Fourier imaging techniques with conventional spin echo times. However, the latter can be extended to low echo times by combining three-dimensional acquisition with short radio pulses and low pulse gradients down to 2·10...