Sharkskin
Polypedia > Defects in polymers
Shark skin | ||
The instabilities of melt flow or melt flow, associated with the surface defects of polymer extruded products and are commonly known as the "Shark skin effect". The extrusion of molten polymers is usually limited by the appearance of an instability of the elastic surface known as shark skin. Melt fracture is a distortion of the finish of the extruded product. The appearance of instabilities is related to a large number of causes, one of the causes presented is the melt fracture. The phenomenon of shark skin has been less studied than fusion fracture, but it is probably a major problem in industrial extrusion. Shark skin is a surface defect that often occurs in the extrusion manufacture of profiles, tubular and flat film (cast), blow molding and coatings. |  | |
| Types of fracture | ||
The fracture of the molten polymer can adopt a variety of arrangements that are named according to the geometry they form. It is more common to find this defect in polymers of high molecular weight and narrow distribution of molecular weights, and when working at low temperatures. |  | |
| What causes the formation of the shark skin phenomenon? | ||
|  |