Probing structure–heterogeneous nucleation efficiency relationship of mesoporous particles in polylactic acid microcellular foaming by supercritical carbon dioxide

Abstract

Heterogeneous nucleating agents that can improve cell morphology of polymer foams have been studied extensively, however, the exact relationship among particle structure, surface modification and nucleating efficiency still remain elusive. Previously, we demonstrated that mesoporous structure benefited nucleating efficiency by comparing solid silica particles and mesoporous particles (MCM-41). Herein, the feasibility of using another type of mesoporous particles, namely, SBA-15 as a nucleating agent for polymer foaming was investigated, but surface modification issue was emphasized. Results reveal that SBA-15 particles show excellent nucleation performance on polylactic acid foaming, and such nucleating effect are dependent on the surface modification. The surface modification using fluorinated silane significantly decreases nucleation energy barrier, and thus shows the highest nucleation efficiency. This work provides a comprehensive insight into structure–nucleating efficiency relationship for mesoporous particles, and highlights the importance of surface modification as a structural factor to optimize the design of effective nucleating agents for polymer foaming.