detrmine material typ from hardness test

No, this would only work for a well-defined material (especially, density & MW) having a known T curve.
For example, the same material can have different Shore nummbers at a given temperature depending upon filler or density (if a celluar material).
See catalog pages 3250 for Neoprene rubber of different hardness in A very brief comparison of the various Shore scales is on p. 3242.

thank's kenvlach,

but if the material IS well defined in terms of
density, MW(what is MW for cortesy) and
SHORE scale & value is available in line with

Would this be sufficient to distinguish brittle
from ductile stuff - speaking about homogenous
plastics as duro/thermoplast type plate/stick/bar
(no rubber, foam, composite) only ?

By ductile vs brittle I mean:
ductile: break at ultimate strenght at finite strains
does not break easily with impacts
brittle: break at about yield strength w/o any much strain
does break under impact e.g. droptest

Thanks again,
Frank

to focus in, I'd intend the 'extra hard'
range of the picture in the link

Regards,
Frank

Hi,
MW = molecular weight is proportional to degree of polymerization.
I think of Shore hardness for 2 things: specifying properties & a rough QC method to determine degree of polymerization. I've never heard of it being used to identify a material, but yes, it could give information for that purpose in conjunction with other observations and meaasurements.

Re your original question "if a given polymer materials behaviour can be characterised reliably as being brittle or ductile at a given Temperature by, say, a SHORE hardness value?
-- I would agree that a given set of solid plastic samples of the same material but different MWs (& crosslinking, if applicable) could be arranged in order of Tg by doing hardness measurements.

Hello,

you say "I would agree that a given set of solid plastic samples of the same material but different MWs (& crosslinking, if applicable) could be arranged in order of Tg by doing hardness measurements". I assume Tg is the glass transition temperature.

I'am unable to derive a statement wrt the question asked, so I conclude the answer is a clear 'maybe'. Concluding further that the conclusion is, that plastics, as with metals, can't be judged being ductile or brittle by means of a hardness test alone.

Frank Exius
IFE Bonn Germany