Creep is a mechanical behavior of materials that deformation
accumulates as time evolves under constant loading, temperatureand humidity. It is an important physical property that should be
taken into consideration for the development of composite materials which undergo long-term loading, especially at high temperature and humidity to ensure long-term stability of strength and
structural integrity. Park and Balatinecz [19] demonstrated
improved creep property for wood-fiber reinforced polypropylene
composites with increasing wood-fiber content and fiber–matrix
interfacial modification with a wetting agent. Cyras et al. [20] conducted flexural creep tests on sisal-fiber-PCL (polycaprolactone)-
starch composites at different temperatures. The creep compliance
increased with the increase of temperature and with the decrease
of the fiber content. They utilized a four-parameter Burgers model
to quantify the creep behavior of the composites. Alvarez et al. [21]
investigated the effect of fiber content on the flexural creep property of sisal fiber reinforced cellulose derivatives/starch composites, and they found a significant improvement of the creep
resistance of the polymeric matrix due to the addition of sisal
fibers to the composites. They also applied various mathematical
models to model the creep property of the composites, which
included the Norton equation, a creep power law and a fourparameter Burgers model.