In the last years, a new family of modified PP was developed, the well-known high melt strength polypropylene (HMS-PP). This product is characterized by a small content of long-chain branches and high polydispersity; the presence of long-chains has an enormous influence on its melt properties.

Due to its inherent nature, polypropylene lacks melt strength. HMSPP contains long chain branches and consequently exhibits significantly high melt strength. These HMSPP grades offer unique balance of process-ability and high melt elasticity required for foaming, thermoforming, and extrusion.

There are many routes for production of HMS-PP. It is very known that the resistance of the melted (RF) increases with the molecular weight. Another theoretical possibility for the increase of RF would be increasing the interlacement level. As PP is a linear polymery this possibility was little explored.
The increase of the molecular weight causes the decrease of the index of fluidity. The ramification formation of long chain doesn't alter the fluidity index and also improves the extensibility.
HMSPP has as characteristic the high resistance of the melted allied to great extensibility.

¤ HMS labels the product technology and process patented developed by IPEN in partnership with BRASKEM and EMBRARAD

¤ It consists of a new type of irradiated PP characterized by having a ramified molecular structure

¤ The market objective is all the processes of PP transformation that demand a large amount of elongation of melted PP

¤ Increase of molecular weight and creation of long ramifications are the state of the art to solve the problems of PP process

The main applications of HMSPP are: - extrusion, compound foils extrusion, films, thermoforming, coatings, foams and blow. The melted low resistance has limited the participation of PP in these segments that impedes or harms those processes.

HMSPP provides more elasticity to the polypropylene in the melted phase. That material, known by HMS-PP (high melt strength polypropylene), it is winning market in all Europe, for environmental reasons, where the industry started to apply in the production of foams for several uses, mainly in dashboard of vehicles, because they are easier to be recycled. The pieces produced employing the mixture of several other plastic resins offers many obstacles to recycling could generate unfeasible.