Poly(L-lactic acid) (PLLA) is regarded as one of the most promising green bio-based polymer materials in industrial application

because of its excellent biodegradability

biocompatibility

high mechanical strength and easy processing performance. However Poly(L-lactic acid) (PLLA) exhibits poor toughness

low crystallization rate and poor heat resistance

these inherent drawbacks limit its development and application in engineering

electronics

electrical and automotive engineering

and 3D printing. Progress in improving the heat resistance of poly(L-lactic acid) are reviewed in this article. The heat resistance of PLLA were enhanced through several methods

such as adding nucleating agents

preparing stereo-complex microcrystal complexes

and blending with nano-particles and high heat resistance polymer materials

which enlarged its application in engineering fields.