PLA Foamed with Chemical Foaming Agents

CFAs influence the viscoelastic properties of the matrix and the cell morphology of foamed plastics in different manners, because of the differences in their thermal decomposition behaviors [81]. Endothermicity has been reported to be a desirable property because the foaming agent absorbs heat during its decomposition, which cools the polymer, increases the viscosity of the melt, stabilizes the cellular structure, and reduces cell coalescence [20, 21]. Smaller cells improve 

TABLE 17.9 Cell Morphology of Microcellular Injection Molded Neat PLA and PLA/Cellulosic Fiber Composites [3] 

Samples Density (kg/m ) Cell Size ( im) Cell Density (ceUs/cm ) 

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