Melt flow index hydrocarbon

Styrene-based thermoplastic elastomers (see Chapter 4) are sensitive to oxidation since they contain unsaturated soft segments. These elastomers are manufactured by solution polymerization process in aliphatic hydrocarbons. In order to prevent autoxidation during the finishing steps (stripping, drying), which manifests itself by a rise in melt flow index and discoloration of the raw polymer, antioxidant is added to the polymer solution before finishing. Hence the antioxidant has to be soluble in the polymerization solvent. 

Features Flexible transparent hydrophobic coprocessable with oletinic plastics, hydrocarbon elastomers processes at relatively low temps. exc. chem. resist. bondable to itself and other substrates Properties Pellets or agglomerate melt flow index 15 (265 C, 5 kg) sp.gr. 

Solubility of PE increases with increasing melt flow index (MFI) but decreases with increasing density and crystalline nature. PE will dissolve slowly above 50°C in hydrocarbons, chlorinated hydrocarbons [4], and higher aliphatic esters and aliphatic ketones [5], but is insoluble below 50°C in all common solvents. 

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