| Polylactide (PLA) has excellent performance, but the nature of brittleness and thethermal instability affects its processing behavior and performance, so theperformance-enhancing of PLA has been extensively investigated in polymer research area.Due to the unique properties of ionic liquids (ILs), they can act as a potential functionaladditive in polymer research field. In this paper, two kinds of imidazolium ionic liquids([EOEMIM][BF4] and [AOEMIM][BF4]) were adopted to melt-blend with two grades ofPLA(2002D and4032D). In order to provide a theoretical basis for the design and synthesisof the new ILs to apply in PLA, the compatibility between PLA and ILs was studied, andthe influences of ILs on the PLA chain movement and its structure evolution during themelting and cooling process were investigated. In add ition, the processing stability, themechanical and thermal properties of PLA were discussed. The results are as follows:1. By van der Waals force interactions,[EOEMIM][BF4] and [AOEMIM][BF4] havegood compatibility with2002D PLA, and [AOEMIM][BF4] has better compatibility with2002D PLA. But the compatibility between ILs and4032D PLA is poor.2. The addition of [EOEMIM][BF4] and [AOEMIM][BF4] can reduce the balancetorque of2002D PLA and4032D PLA in the process, where they play the role of thelubricant. And they can keep the stability of PLA2002D in the process, but the processingstability of the4032D PLA has no influe nces. In addition, the existence of the two ILs cancatalyze the thermal decomposition of2002D PLA and4032D PLA at a high temperature.We also find that [EOEMIM][BF4] is better to improve the processing stability and hightemperature stability of the two grades of PLA.3.[EOEMIM][BF4] and [AOEMIM][BF4] have certain plasticization effects on2002DPLA, but their plasticization effects on4032D PLA are not obvious. And both two ILs canaccelerate the crystallization of2002D PLA and4032D PLA owing to their nucleatingeffects. The results also indicate that [EOEMIM][BF4] mainly shows the plasticizing effect,and [AOEMIM][BF4] mainly plays the role of nucleation.4. In terms of mechanical properties, the addition of [EOEMIM][BF4] and[AOEMIM][BF4] reduces the tensile strength of2002D PLA, but its elongation at breakand impact strength increase. For4032D PLA, its tensile strength, elongation at break andimpact strength can be improved by adding [EOEMIM][BF4] and [AOEMIM][BF4].However, their improvement effects on mechanical properties of4032D PLA are less than2002D PLA blends samples. 5. The addition of [EOEMIM][BF4] and [AOEMIM][BF4] has little effects on theantistatic properties of2002D PLA and4032D PLA. |
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