Meaning
Thermoplastic elastomers containing alternating blocks of highly crystalline ethylene and amorphous octene segments provide a balance of flexibility and heat resistance. Application of an ethylene-octene block copolymer enhances the impact strength of rigid polymers like polypropylene at low temperatures. This material acts as an effective impact modifier in automotive and industrial applications.
Toughness Modification
Compounding rigid thermoplastics with elastomeric modifiers increases the resistance to brittle failure. The crystalline blocks of the copolymer anchor into the polypropylene matrix, while the amorphous octene blocks provide high elasticity. This structural arrangement prevents the modifier from migrating or coalescing during subsequent moulding cycles.
Melt Rheology
Processing blends containing these block copolymers requires careful control of the shear rate and melt temperature. The unique block structure affects the viscosity of the melt, making it sensitive to shear thinning. Molders must adjust injection speeds to avoid excessive friction at the gates.
This adjustment prevents thermal degradation of the elastomer and ensures a uniform surface appearance.
Economic Value
Using high-performance copolymers allows molders to reduce wall thicknesses without compromising the mechanical integrity of the final part. While the initial resin cost is higher than that of standard polyolefins, the reduction in cycle times and material usage yields a lower overall part cost. Additionally, these materials are compatible with regrind recycling, allowing scrap to be reprocessed without a significant drop in impact performance.
This compatibility supports sustainable manufacturing practices while maintaining strict quality standards. Choosing a high-performance copolymer over standard impact modifiers therefore reduces total manufacturing expenses.
