A Study on the Role of Clay Nanoparticles and Temperature on the Creep Behavior of Polyethylene Matrix Nanocomposite

Abstract

Objective: In the current research, the creep behavior of polyethylene (PE) matrix nanocomposites reinforced with different content of clay nano particles (i.e., 0, 1, 3, 5, 10wt%) at different temperatures (25 and 50℃) has been investigated. Methods: In order to produce composite samples of pure PE reinforced with different percentages of clay (0, 1, 3, 5 and 10% by weight), a twin extruder was used in the temperature range of 200-230℃. Also, to produce the standard samples, an injection machine was used using in the temperature range of 220-230℃. The samples were subjected to a constant load, typically around 0.7 to 0.8 times the yield strength, at 25 and 50℃ , and at constant strain rate of 0.1min-1. Results: The creep investigations showed that for PE and its nanocomposites the creep trend could be divided into primary, secondary, and tertiary stages. The length of each stage depended strongly on both temperature and the stress level at which the samples tested as well as the clay content. It was observed that adding nano particles in small amounts (1wt%) led to an increase in the length of the creep life of PE and it also improved this property in both temperatures. Conclusion: It was observed that increasing test temperature from causes to decrease the creep strength as well as a rapid onset of plastic deformation for all materials including PE and its nanocomposites. PE nanocomposites with higher than 1wt% clay exhibited a noticeable drop in creep strength particularly at 50℃.