L. Averous et al., EVOLUTION OF THE 3-DIMENSIONAL ORIENTATION DISTRIBUTION OF GLASS-FIBERS IN INJECTED ISOTACTIC POLYPROPYLENE, Polymer engineering and science, 37(2), 1997, pp. 329-337
The mechanical properties of fiber reinforced thermoplastics depend on
the characteristics of the fibers, such as their three-dimensional or
ientation distribution, which is the result of the processing conditio
ns and of the initial products before mixing. Different composites wer
e obtained by injection of reinforced isotactic polypropylene containi
ng 30 wt% fibers. Different size distributions of fibers were investig
ated. Their average lengths range from 60 to 470 mu m. Specific new to
ols were developed by combining microscopy and image analysis to deter
mine the microtextural characteristics of the fibers, such as their si
ze distribution or their orientation in the matrix. Our technique allo
ws the following of the size distribution evolution of the fibers as t
he composite is processed. The three-dimensional orientation of the fi
ber is established using the in-plane angle and the angle of inclinati
on. The evolution of the three-dimensional orientation distribution is
studied in the sample, by differentiating central and border behavior
and also as a function of fiber size. It is concluded that the coupli
ng of scanning electronic microscopy with image analysis is an interes
ting technique that allows the 3-D orientation of the fibers to be det
ermined. This technique is validated by showing that the results obtai
ned agree with those that other authors obtained on comparable materia
ls.