Abstract:

In the present study， the effects of varying proportions of epoxy soybean oil （ESO）/tung oleic anhydride （TOA） gel on the properties of polylactic acid （PLA）/lignin （LM） composites were investigated. The mechanical properties， crystallization behavior， dynamic mechanical performance， and thermal stability of the composites were characterized using scanning electron microscopy， dynamic mechanical analysis， thermogravimetric analysis， and rotational rheometry. The results indicated that the ESO/TOA gel was dispersed effectively in the PLA matrix， reacting with both PLA and lignin to improve compatibility and toughness. The gel enhanced molecular chain mobility， increasing composite crystallinity， though it slightly reduced thermal stability. The fracture elongation of the composites rose significantly with higher TOA content， increasing from 6 % （pure PLA） to 32 %. At an ESO∶TOA ratio of 5∶5， the gel particles achieved optimal dispersion， yielding the best overall performance， including an impact strength of 4.1 kJ/m².

Key words: poly（lactic acid）, epoxy soybean oil, tung oleic anhydride, lignin, mechanical property