Protopasta HTPLA is PLA that can be heat treated for higher temperature resistance compared to standard PLA. Heat treating changes the material structure from amorphous to crystalline. While amorphous structures change drastically near their glass transition temperature (Tg), crystalline structures maintain useful properties above Tg and towards melting (Tm). Thus, heat treating greatly increases the useful range as seen by the difference between Tg and Tm in the DSC results below.