Curdlan (CD) is a high-molecular-weight bacterial exopolysaccharide with linear β-(1 → 3)-glycosidic linkages. In a previous report, we showed that CD branched esters, namely, CD isobutyrate (CDiBu) and CD pivalate (CDPi), had very high melting temperatures (T_m = ca. 340 °C) that were similar to their thermal degradation temperatures (T_d), which prevented their thermal processing [J Polym Res 2017; 25:181]. To solve this problem, a series of CD branched and linear mixed esters, CD isobutyrate heptanoate (CDiBuHep) and CD pivalate heptanoate (CDPiHep), were synthesized and characterized. No significant difference in T_d was observed between CD homoesters and mixed esters. T_m values were observed for CDiBuHeps, but not for CDPiHeps, indicating that CDiBuHeps and CDPiHeps were crystalline and amorphous polymers, respectively. T_m values of CDiBuHeps were controlled from 280 °C to 72 °C by adjusting the degree of substitution ratios of branched and linear carboxylic acids. These T_m values were lower than the T_d, suggesting that thermal processing was applicable to these mixed esters. All films of mixed esters were colorless and highly transparent, and their mechanical properties ranged from rigid to soft and rubbery states depending on the ratio of the linear ester group.

Curdlan（CD）是具有线性β-（1→3）-糖苷键的高分子量细菌胞外多糖。在先前的报告中，我们显示了CD支链酯，即CD异丁酸酯（CDiBu）和CD新戊酸酯（CDPi），具有非常高的熔融温度（T _m  =约340°C），与它们的热降解温度相似（T _d），这阻碍了它们的热处理[J Polym Res 2017; 25：181]。为了解决该问题，合成并表征了一系列CD支链和线性混合酯，CD异丁酸酯庚酸酯（CDiBuHep）和新戊酸庚酸酯CD（PiPiHep）。在CD均酯和混合酯之间，没有观察到T _d的显着差异。Ť_米对于CDiBuHeps，没有观察到CD-Heps值，但对于CDPiHeps则没有，表明CDiBuHeps和CDPiHeps分别是结晶聚合物和无定形聚合物。通过调节支链和直链羧酸的取代度，将CDiBuHeps的T _m值控制在280°C至72°C。这些T _m值低于T _d，表明热处理适用于这些混合酯。所有混合酯薄膜均是无色且高度透明的，其机械性能取决于直链酯基团的比例，范围从刚性到柔软和橡胶状。