Meaning
Formation of localized, high molecular weight domains within a polymer melt where polymer chains have bonded together to create insoluble nodes. Thermal degradation via micro gel cross linking occurs when heat or shear triggers a chemical reaction that links individual molecules into a three dimensional network.
Defect Formation
Particles that fail to melt or flow at the same rate as the surrounding resin create visible imperfections in thin films or surface bumps in moulded parts. The presence of micro gel cross linking reduces the optical clarity of the part and creates points of stress concentration.
Reaction Driver
Residual catalysts from the polymerization process or excessive residence time in the extruder barrel often initiate these unwanted bonds. Controlling micro gel cross linking requires precise temperature management and the use of secondary stabilizers that quench the radical species before the network can grow.
Mechanical Impact
Large clusters of cross linked material interfere with the elongation properties of the polymer and can cause premature failure under load. Because these gels do not integrate with the rest of the matrix, they act as internal flaws that weaken the bond between the molten layers during the injection process. This lack of integration creates a boundary where cracks can initiate and propagate when the finished part is subjected to mechanical vibration or impact.
