The importance of the bioplastic polylactide has increased significantly in the recent years, followed by a permanent increase in production capacity, which has increased its competitiveness compared to conventional plastics. Because of further developments in the last years, PLA is not only available for competitive prices, but also has equal material and processing properties. Due to its similar properties to fossil-based polystyrene (PS), it has potential to substitute foamed PS products, which can increase the sustainability and material efficiency of foamed products. However, the low molecular weight of commercial PLA, its sensitivity to hydrolysis during processing and the very low rate of crystallization inhibit the production of low density foams and uniform cell morphology. Therefore, one way is to modify PLA cost-effectively in order to increase the melt strength and to realize a strain hardening effect. In the literature several approaches, but with limitations or disadvantages, can be found. On the one hand, the chemical modification often takes place in a batch process, which is not applicable in real plastic processes. Often the commercially available modifier (multifunctional epoxide) is used. On the other hand, only certain types of PLA are considered, which means that the effects of the properties of PLA (D-content, molecular weight and acid number) on the modification have not yet been clarified. The aim of this work is to investigate the molecular effects of different PLA on the chemical modification to enhance the melt properties and to evaluate the final impact on the expansion behavior.