Cellulose ester compositions

A cellulose ester composition comprising:

• (a) a first cellulose ester comprising:
• (i) a plurality of propionyl substituents,
• (ii) a plurality of acetyl substituents,
• (iii) a plurality of hydroxyl substituents,
• wherein the degree of substitution of the propionyl substituent of the first cellulose ester (“DSPr1”) is in the range of from about 1.1 to about 2.87,
• wherein the degree of substitution of the acetyl substituent of the first cellulose ester (“DSAc1”) is in the range of from greater than 0 to 0.3,
• wherein the degree of substitution of the hydroxyl substituent of the first cellulose ester (“DSOH1”) is in the range of from about 0.05 to about 0.7,
• wherein the weight average molecular weight of the first cellulose ester (“Mw1”) is in the range of from about 60,000 Da to about 200,000 Da;
• and
• (b) a second cellulose ester comprising:
• (i) a plurality of propionyl substituents,
• (ii) a plurality of acetyl substituents, and
• (iii) a plurality of hydroxyl substituents,
• wherein the degree of substitution of the propionyl substituent the second cellulose ester (“DSPr2”) is in the range of from about 1.1 to about 2.87,
• wherein the degree of substitution of the acetyl substituent of the cellulose ester (“DSAc2”) is in the range of from greater than 0 to 0.3,
• wherein the degree of substitution of the hydroxyl substituent of the cellulose ester (“DSOH2”) is in the range of from about 0.05 to about 0.7,
• wherein the weight average molecular weight of the second cellulose ester (“Mw2”) is in the range of from about 15,000 Da to about 60,000 Da;
• wherein the weight average molecular weight of the cellulose ester composition (“Mw”) is greater than Mw2 but less than Mw1,
• wherein Mw, Mw1, and Mw2 are determined by gel permeation chromatography (“GPC”) using tetrahydrofuran (“THF”) as a solvent,
• wherein the first cellulose ester and the second cellulose ester are miscible,
• wherein the cellulose ester composition has a single glass transition temperature (“Tg”),
• wherein the cellulose ester composition further comprises 2 wt. % to 12 wt. % of a blowing agent,
• wherein the cellulose ester composition further comprises 10 wt. % to 30 wt. % of an additive chosen from a plasticizer or a flame retardant, the plasticizer is chosen from triethylene glycol 2-ethyl hexanoate, epoxidized soybean oil, or acetyl triethyl citrate, and the flame retardant is an organophosphorous compound chosen from resorcinol bisdiphenyl phosphate, bisphenol A diphenyl phosphate, resorcinol bis(di-2,6-xylyl phosphate), or tricresyl phosphate, and
• wherein when the cellulose ester composition comprises a flame retardant, it further comprises another additive to improve the adhesive properties, wherein said another additive is different from the said flame retardant and said another additive is a plasticizer.