Dissertations in Forestry and Natural Sciences

Taneli Väisänen: Effects of Thermally Extracted Wood Distillates on
the Characteristics of Wood-Plastic Composites
Table 3. Some of the parameters used in injection molding.
Parameter
Value
Heater temperature (°C)
Mold temperature (°C)
Heater 1 Heater 2 Heater 3 Heater 4 Nozzle
100–150 140–165 165–175 180 185–195
Fixed
Movable
50–75 50–75
Cooling time (s) 20–35
Holding pressure (MPa) 350–800
Holding time (s) 15.0
Injection pressure (MPa) 80–100
In comparison with the specimens prepared from LG, the UF
specimens were injection molded at higher heater and mold
temperatures but at lower holding pressures. In general, the
WPCs containing distillates required lower holding and
injection pressures for injection molding. However, the addition
of distillates resulted in smoother surfaces of the specimens, and
thus, the specimens started to stick to the mold. Therefore,
longer cooling times were used for the WPCs treated with
distillates. At least 50 pairs of specimens were prepared from
each material type, and the specimens were stored in plastic
bags under laboratory conditions.
6.2 MECHANICAL PROPERTIES
The mechanical properties of the WPCs were determined using
the injection-molded specimens. The measurements were
carried out within two weeks after the sample preparation, and
the samples were conditioned and stored in the laboratory
between the measurements.
In studies I, III and IV, the tensile and flexural properties of
the WPCs were characterized. Moreover, Charpy’s impact
strengths were determined in studies III and IV. A total of ten
specimens of each material type were examined in each test.
78 Dissertations in Forestry and Natural Sciences No 222