Talk:Melt flow index

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Untitled[edit]

question

the MFI is inversely proportional to the viscosity. But it's the any equation relation the two? what is the proportionality coef. for the PP?

thank you

Viscosity is not usually constant (polymers are very non-newtonian fluids), with dependance on the flow rate. This means that there is no single constant that applies here.

Melt flow Index[edit]

I was wondering if this page could be editted in some way to give further mention of the MFI's effect on mechanical properties. It speaks of how if he MFI is too low properties will be effected, but does not give correlation between the factors. - Again this is too simplistic, and depends on the material under discussion.

194.126.226.253 11:07, 30 March 2007 (UTC)

As far as I know the Melt Flow Index can be expressed as the melt flow rate (MFR) OR the melt volume (MVR) rate. Should not both methods be mentioned? The Melt Volume Flow Rate measures the time a predetermined volume of a thermoplastic polymer takes to pass through a capillary of predetermined diameter. Also the melt flow index, since it encompasses both the MFR and MVR, is not synonymous with the Melt Flow Rate. — Preceding unsigned comment added by Sketchbookshark (talkcontribs) 21:45, 8 August 2012 (UTC)

Continued Suggestions[edit]

Melt index lis or examples to discuss or at least off page reference to melt index for injection molding and extrusion, which can be very different, yet have similar mechanical properties.

ABS for example there could be twice the melt flow for injection molding grade than extrusion grade ABS but almost identical properties in their cooled state. As always, it depends. MFI depends highly upon how well polymer chains pass by each other. —Preceding unsigned comment added by 76.6.253.233 (talk) 01:51, 11 September 2010 (UTC)