交联网络和浓溶液中高分子链运动的NMR研究Ⅲ.质子自旋-晶格弛豫时间与凝胶和浓溶液体系中高分子链段的运动

用自旋－晶格弛豫时间（Ｔ１）研究了溶胀的交联聚丙烯酰胺－丙烯酸网络和线型聚苯乙烯溶液中质子的弛豫行为。交联网络中，随着交联度增大，Ｔ１ＣＨ／Ｔ１ＣＨ２的值由１．１７逐渐趋近于１；而线型聚苯乙烯溶液中，Ｔ１ＣＨ／Ｔ１ＣＨ２的值由最稀浓度下的１．７过渡到１。说明在交联网络中，交联度很低时，链段的运动已经相当受约束；但交联度很大时，充分溶胀的交联网络中链段运动仍有一定自由度。而在线型高分子浓溶液中，链段的运动严重受阻，导致自旋扩散效应非常完全，彻底平均掉了各质子间Ｔ１时间的差异。

The NMR Studies of Macromolecular Segment Movement in Crosslink Polymer Network and Concentrated Polymer Solution 3. Proton Spin-Lattice Relaxation and Macromolecular Segment Movement in Gel and Concentrated Polymer Solution Systems

The spin-lattice relaxation time (T 1) is applied to study the proton relaxational behavior in swollen crosslinked polyacrylamide-acrylic acid network and linear polystyrene (PS) solution. With the degree of crosslinkage increasing, the value of T 1CH /T 1CH 2 from 1.17 gradually tends to 1 in crosslinked network, while with PS concentration increasing in linear PS solution, the T 1CH /T 1CH 2 value decreases from 1.7 to 1. The results demonstrate that in well swollen crosslinked network, the segment movement is very restricked even at the very low degree of crosslinkage and a little free at the very high degree of crosslinkage; while in concentrated PS solution, the T 1 difference of different protons is averaged to equal by the completely spin-diffusion effect which is caused by the serious hampering of segment movement.