Peroxide Visbreaking

Molecular Weight

Reduction of the average chain length is the primary outcome of the chemical reaction in the melt. Because peroxide visbreaking targets the longest molecules, it creates a more uniform material that flows consistently through complex tool geometries. Shorter chains result in a lower viscosity.

This change allows the moulder to use lower pressures during the injection phase.

Flow Rheology

Modification of the flow behavior improves the performance of the resin in thin wall moulding and fiber spinning. Since the modified polymer has a higher melt flow index, it can fill intricate parts without requiring extreme temperatures. Peroxide visbreaking also reduces the elastic memory of the melt, which minimizes issues like die swell.

These improvements lead to more stable production runs.

Extrusion Stability

Accurate dosing of the peroxide is necessary to prevent over degradation or inconsistent flow between batches. While the process is efficient, it can leave behind residual chemicals that affect the smell or color of the plastic. Modern extruders use specialized injection systems to ensure the peroxide is mixed thoroughly.

Uniform degradation is the primary factor in maintaining the mechanical properties of the finished product.