Meaning
Elastomeric particles dispersed within a rigid polymer matrix govern the mechanical toughness and impact resistance of the resulting compound. These rubber domain size measurements describe the average diameter of dispersed phase nodules that prevent crack propagation through the material. Smaller nodules provide superior clarity and gloss, while larger ones offer improved energy absorption during mechanical stress.
Processing Correlation
Injection moulding parameters dictate the final morphology of these inclusions during cooling. High shear rates during the filling stage break down aggregates into smaller zones, while extended residence times at high temperatures encourage particle coalescence through thermal motion. Stabilizing this morphology requires precise control over screw speed and back pressure to ensure uniform energy distribution across the melt.
Consistent cooling rates keep the dispersed phase locked in a stable distribution before solidification prevents further movement.
Economic Divergence
Virgin resins arrive from suppliers with a set range of internal distributions calibrated for standardized performance. Regrind materials introduce variation as repeated thermal cycles alter the nodule distribution through repeated shearing and agglomeration. Processors who mix regrind into virgin stock often face drift in physical properties because the internal structure loses the initial morphology designed by the original manufacturer.
Cost differences arise when degraded internal structure forces a moulder to adjust cycle times or accept a reduction in product drop test performance.
Performance Boundaries
Datasheet values represent ideal conditions produced under laboratory control rather than the output of a standard production line. Moulders achieve parity with these specifications only if the tool geometry and cooling system maintain consistent shear history throughout every part. Deviations in wall thickness or gate location create local velocity gradients that shift the internal structure away from the intended design.
Correcting these shifts demands an adjustment to the injection profile because the material relies on the physical arrangement of its phases to satisfy mechanical requirements.
