中文摘要：

采用溶剂成膜法制备了柠檬酸三乙酯（TEC）、大豆油和甘油三乙酸酯增塑的聚（3-羟基丁酸酯-co-4-羟基丁酸酯）共混物，考察了增塑剂的种类及其用量对共混物热学和力学性能的影响。用差示扫描量热仪（DSC）和电子拉力试验机分别测定共混物的热性能和力学性能。结果表明，三种增塑剂中质量分数为5％的TEC对共聚物的增塑改性效果较好，与纯聚酯相比共混物的结晶温度（Tmc）下降了2．0℃，结晶焓（△Hmc）基本保持不变。当TEC的质量分数为20％时，聚（3-羟基丁酸酯-co-4-羟基丁酸酯）的Tg下降21℃。TEC共混物能保持15．8MPa的拉伸强度和588％的断裂伸长率。

英文摘要：

Blends of P（3-hydroxylbutyrate-co-4-hydroxylbutyrate）[P（3HB-co-4HB）] plasticized by triethyl citrate （TEC）, soybean oil （SO） and glycerin triacetate （TA） have been prepared by a solvent casting film method. The effects of varying the type and content of plasticizer on the properties of the polymer blends have been studied. The crystalline behavior and mechanical properties of the blends were investigated by differential scanning calorimetry （DSC） and tensile measurements. The results showed that the effect of TEC on the crystalline temperature （Tmc） and crystalline enthalpy （ΔHmc） is the smallest of the three plasticizers. For a mass ratio of TEC of 5 %, Tmc decreased by 2 ℃ and ΔHmc remained almost unchanged as compared with the pure polymer. Furthermore, adding TEC had a significant effect on the glass transition temperature （Tg） of the blend and for a mass ratio of TEC of 20 %, Tg decreased by 21 ℃;. In the case of a mass ratio of TEC of 5 %, the TEC/polymer blend had a tensile strength of about 15.8 MPa and an elongation at break of about 588 %, comparable to the values for the pure polymer.