The fracture behavior of PVC/MBS blend changes significantly, dependent on which occurs mainly, crazing
or shear yielding.
Figure 4b is the fracture surface of a 50 wt% PS/50 wt% PPO blend; it shows patch patterns separated by river patterns, which indicates multiple crazing
in the vicinity of the fracture surface.
the effect of the degree of crystallinity and of the crystal morphology) on the solvent induced crazing
process occurring in the amorphous phase of the polymer needs to be further investigated.
Under impact conditions, chain scission is likely to become important (37), thus it can be speculated that crazing
will be favored and voiding and fibrillation will be aided by the scission processes rather than by viscous disentanglement via repetition, as occurred in slow strain-rate tests such as tensile test.
However, it is noted that while crazing
evidence was observed in each of the pressure deflection tests, ultimate failure occurred by yielding and drawing of remaining material ahead of the notch.
As the constraint was reduced, multiple crazing
continued to blunt the tip but it was also accompanied by the formation of large voids.
, the energy barrier comes from the requirement of the polymer molecules to slide past one another (via reptation) and to undergo conformational changes.
One of the goals of this paper is to correlate the residual mechanical properties measured in the previous study to crazing
stress, relative craze density, and strain rate.
It may be suggested that polymers can be toughened by adding some fillers to promote crazing
Previously, a wide variety of techniques have been employed to study crazing
behavior in polymers.
2) SEM (scanning electron microscope) and TEM (transmission electron microscope) observations on the broken surface revealed that shear yield and crazing
occurred in a whitened portion, and crazing
was observed only near the surface of the broken section in a non-whitened portion.
The toughening mechanism investigation shows that a widespread crazing
zone is generated in the crack tip damage zone.
In some grades a single dominant craze is evident but in most tough grades multiple crazing
occurs, Load is measured by using a standard load cell.
impact resistance is improved by shear yield  or by crazing
rather than shear yield .
The enhanced ductility of rubber-toughened plastics and their resistance to fracture have been explained via a mechanism of crazing
and shear yielding of the glassy polymer matrix (1).