The mechanical response of thermoplastic polyethylene monoliths containing longitudinal microcapillaries

This paper is concerned with the mechanical compressive and tensile behaviour of polyethylene microcapillary monoliths (MCMs). MCMs are a voided polyethylene microstructure with two dimensional arrays of microcapillaries and where the polymer monolith is fabricated by the heat melding of microcapillary films (MCFs). MCFs are plastic films that resemble a tape but with an array of capillaries embedded within it. A reference monolith (MCM without capillaries) was also fabricated and tested under the same conditions as both low and high-voidage MCMs. The effect of the capillaries and voidage under compression of the polymer samples were evaluated taking as a standard, the reference monolith and a mathematical model was used to compare with the observed MCM capillaries response. Additionally the tensile mechanical drawing of low-voidage MCMs at different temperatures was carried out. The low-voidage MCM was mechanically drawn in the capillary direction with the objective of obtaining smaller diameter capillaries and the results show that with drawing, the initially circular section microcapillaries develop into a profile that follows the outer rectangular section of the monolith.