Meaning
Quantitative measurement of phase boundary adhesion in immiscible polymer blends evaluates how effectively a reactive agent or block copolymer reduces interfacial tension. Evaluated through mechanical strain recovery and morphology domain size, compatibilization efficiency dictates whether recycled polyolefin mixtures retain tensile strength under load. Poor performance at the interface leads to delamination during injection moulding.
The metric applies exclusively to multiphase polymer systems where discrete domain dispersion determines bulk mechanical properties.
Interfacial Reduction
Interfacial tension drops when block copolymers segregate to the boundary between incompatible polymer phases. Adding maleic anhydride grafted polypropylene to polyolefin blends decreases domain size, rendering compatibilization efficiency a critical variable during compounding. Small domain sizes prevent microcrack propagation under mechanical stress.
When the additive concentration passes the critical micelle concentration, additional compatibilizer forms isolated micelles in the matrix rather than migrating to the interface.
Morphological Stability
Thermal stress during repeated melt processing threatens the stability of dispersed polymer domains. Maintaining high compatibilization efficiency prevents coalescence of the dispersed phase during long barrel residence times. Without stable phase morphology, molten resin experiences phase separation in the runner system of an injection mould.
Moulded components then exhibit surface peeling and premature brittle failure under impact.
Ductility Recovery
Retaining impact strength in recycled resin mixtures requires mechanical stress transfer across phase boundaries. Sustained compatibilization efficiency restores elongation at break toward virgin material values without sacrificing flexural modulus. Lower values of compatibilization efficiency leave sharp mechanical interfaces that act as stress concentration sites.
