Cellulose ester particulates having reduced moisture content for foam sheet production processes

A method of forming a dried particulate material, the method comprising:

• (a) providing a foamable particulate composition comprising a cellulose ester and a plasticizer, the foamable particulate composition having a moisture content;
• and
• (b) introducing the foamable particulate composition into a drying system, thereby reducing the moisture content and forming the dried particulate material,
• wherein the drying system comprises contacting the composition with a drying vapor stream passed through the drying system, wherein the drying vapor stream is vented until the moisture content is 1 wt % or less,
• wherein the drying vapor stream is air,
• Wherein the foamable particulate composition is dried within the drying system at a temperature at least 60° C. below the Tg of the composition, but not more than 80° C., not more than 70° C., or not more than 60° C.