We have demonstrated that solid-state and time-domain Nuclear Magnetic Resonance spectroscopy (NMR) techniques are effective in monitoring the degradation site of poly (urea-urethane). We prepared two types of commercial poly (urea-urethane), Urethane-A and Urethane-B, and aged them at 100 °C for up to 10000 h. We performed tensile strength tests and solid-state NMR experiments, in which ¹³C and ¹⁵N NMR spectra and T₂ were collected. The tensile strength of Urethane-A decreased, increased and decreased again, whereas that of Urethane-B decreased at a lower rate with aging. Solid-state NMR experiments clearly showed that the degradation of Urethane-A was caused by molecular chain scission and cross-linking in its urea bonds, and that of Urethane-B occurred owing to molecular chain scission in its urethane bonds. T₂ had three components, short T₂ (T₂^S), intermediate T₂ (T₂^I) and long T₂ (T₂^L), whose fractions were x_S, x_I and x_L, respectively. We have demonstrated that molecular chain scission in urea bonds decreases x_S and increases x_L, and that in urethane bonds increases T₂^I and T₂^L without changing all the T₂ fractions.

我们已经证明，固态和时域核磁共振波谱（NMR）技术可有效地监测聚（脲-氨基甲酸酯）的降解位点。我们准备了两种类型的商品化聚脲（Urea-Aurethane），Urethane-A和Urethane-B，并在100°C下老化了10000 h。我们进行了抗张强度测试和固态NMR实验，其中¹³ C和¹⁵ N NMR光谱和T ₂被收集。氨基甲酸酯-A的抗张强度随着老化而降低，增加和降低，而氨基甲酸酯-B的抗张强度以较低的速率降低。固态NMR实验清楚地表明，氨基甲酸酯-A的降解是由其脲键的分子链断裂和交联引起的，而氨基甲酸酯-B的降解是由于其氨基甲酸酯键的分子链断裂引起的。T ₂具有三个成分，短T ₂（T ₂ ^S），中间T ₂（T ₂ ^I）和长T ₂（T ₂ ^L），其分数为x _S，X_我和X_大号，分别。我们已经证明，脲键的分子链断裂降低x _S并增加x _L，而氨基甲酸酯键的分子链断裂增加T ₂ ^I和T ₂ ^L而不改变所有的T ₂分数。