Abstract:Biodegradable poly (butylene succinate terephthalate) copolyester PBST foamed particles were prepared by supercritical carbon dioxide autoclave foaming technology for the first time. 1HNMR spectrum analysis shows that the molar content of succinic acid in PBST is 55%. Differential scanning calorimetry result shows that the glass transition temperature and melting point of PBST are -16 ℃ and 118 ℃, respectively. Thermogravimetric result shows that the decomposition temperature of PBST is 312 ℃. The effects of permeation temperature, permeation time and permeation pressure on the density and the expansion ratio of PBST foamed particles were studied in detail. The result shows that when the permeation temperature increases from 60 ℃ to 80 ℃, the density of PBST foamed particles decreases and the expansion ratio increases. When PBST foamed particles were kept for 1 day, the density of PBST foamed particles increases and the expansion ratio of PBST foamed particles decreases. When the storage time was increased to 7 days, the density and expansion ratio remain unchanged; When the permeation time increased from 1 h to 2 h, the density of PBST foamed particles decreases and the expansion ratio increases; When the permeation time increased from 2 h to 3 h, the density and expansion ratio of PBST foamed particles remain unchanged; When the permeation pressure increased from 10 MPa to 12 MPa, the density of PBST foamed particles decreases and the expansion ratio increases; When the permeation pressure increases from 12 MPa to 14 MPa, the density and expansion ratio of PBST foamed particles remain unchanged. The optimum permeation temperature, permeation time and permeation pressure of PBST foamed particles are 70 ℃, 2 h, and 12 MPa, respectively. SEM result shows that the average pore size of PBST foamed particles is ca. 10 μm. This work can provide experimental basis and theoretical guidance for the application of PBST in the field of green environmental protection and lightweight.