Using the Table 1, explain what happens on the macro scale when elastomers/rubbe

Question

Using the Table 1, explain what happens on the macro scale when elastomers/rubber are heated from below their Tg to above their Tg, and below their Tm to above their Tm. Each description in Table 1 can be used multiple times, or not at all.

Elastomers

                 Temperature from below Tg to above Tg (but still below Tm)

Temperature from below Tm (but already above Tg) to above Tm

Table 1:

Rigid Solid to Rigid Solid (RS to RS)

Rigid Solid to Flexible Solid (RS to FS)

Rigid Solid to Molten Liquid (RS to ML)

Flexible Solid to Flexible Solid (FS to FS)

Flexible Solid to Rigid Solid (FS to RS)

Flexible Solid to Molten Liquid (FS to ML)

Molten Liquid to Molten Liquid (ML to ML)

Not Applicable (NA)

Table 1:

Rigid Solid to Rigid Solid (RS to RS)

Rigid Solid to Flexible Solid (RS to FS)

Rigid Solid to Molten Liquid (RS to ML)

Flexible Solid to Flexible Solid (FS to FS)

Flexible Solid to Rigid Solid (FS to RS)

Flexible Solid to Molten Liquid (FS to ML)

Molten Liquid to Molten Liquid (ML to ML)

Not Applicable (NA)

Explanation / Answer

Whether an amorphous polymer is a thermoplastic or an elastomer depends on its glass transition temperature, or Tg. This is the temperature above which a polymer becomes soft and pliable, and below which it becomes hard and glassy. If an amorphous polymer has a Tg below room temperature, that polymer will be an elastomer, because it is soft and rubbery at room temperature. If an amorphous polymer has a Tg above room temperature, it will be a thermoplastic, because it is hard and glassy at room temperature. So a general rule of thumb is that for amorphous polymers, elastomers have low Tg's and thermoplastics have high Tg's.

below Tm to above Tm it melts FS to ML

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