Influence of moisture content on creep behaviours of polymers

Hello everyone?

Has anybody done any research to investigate the influence of moisture content on creep behaviours of polymers? like how retardation time changes with moisture content if a burgers model applied? i have done creep tests for two materials and fit a burgers model to data. One material shows that retardation time increases with increasing moisture content, while the other one shows retardation time decreases with increasing moisture content. Before i repeat my tests, can any body be kind enough to give me some theoretical guidance or share me some experience on this topic?

Many thanks