Products made of polyethylene used out doors are subjected to UV-degradation. In
fact, many polymers show changes in physical properties during service lifetime, when
they are exposed to sun light and particularity to UV-light. In the present work, the
physical properties and the morphology of blends of high – density polyethylene
(HDPE)/linear-low-density polyethylene (LLDPE) studied before and after exposure to
UV –light.
HDPE was mixed with different weight percent (0, 15, 30, and 45%) of LLDPE using
the two roll mills; the mixing machine is operated at a temperature of 135 oC.
Weathering test was carried out to find the effect of the environment condition on the
physical properties of the polymeric materials by increasing the exposure times to
(100,200,300) hr. The physical properties and the morphology were specified by
measuring the (absorption properties, and densities), for the former, and
photomicrograph for the latter. The results obtained in this work show that the density of
pure HDPE and HDPE/LLDPE blends increased with the increasing the exposure time,
and that immersing the HDPE and HDPE/LLDPE blends in water can produce a variety
of damage and this damage increased with the increasing of the exposure times also, as
the amount of LLDPE is increased in the HDPE/LLDPE blends the amount of water
absorbed and diffusivity coefficient, increase greatly, and from the optical micrograph
results showed clearly the damage obtained due to exposure to UV light for 300 hr for
pure HDPE and HDPE/LLDPE blends.