Adv Polym Technol. 2017;1–13. wileyonlinelibrary.com/journal/adv | 1 © 2017 Wiley Periodicals, Inc. Received: 18 March 2017 | Accepted: 19 July 2017 DOI: 10.1002/adv.21875 RESEARCH ARTICLE Improvements in mechanical strength and thermal stability of injection and compression molded components based on Poly Lactic Acids Clizia Aversa 1 | Massimiliano Barletta 2,1 | Annamaria Gisario 3 | Elisa Pizzi 1 | Michela Puopolo 1 | Silvia Vesco 1 1 Dipartimento di Ingegneria dell’Impresa, Università degli Studi di Roma Tor Vergata, Roma, Italy 2 Dipartimento di Ingegneria, Università degli Studi Roma Tre, Roma, Italy 3 Dipartimento di Ingegneria Meccanica ed Aerospaziale, Sapienza Università degli Studi di Roma, Roma, Italy Correspondence Massimiliano Barletta, Dipartimento di Ingegneria, Università degli Studi Roma Tre, Roma, Italy. Email: barletta@ing.uniroma2.it Funding information LIFE + Programme (2014-2020), Grant/ Award Number: LIFE-PLA4COFFEE ENV/ IT/000744; European Commission Abstract Degradable polymers are limited by their often-insufficient mechanical and thermal properties, which limit their usage to single-use packaging items at room temperature and in dry conditions. In this respect, the present work deals with the manufacture of custom-built Poly Lactic Acids (PLAs), which are designed to be compostable, suit- able for food contact and are characterized by a good compromise between mechani- cal properties and thermal stability. A commercial grade PLA was, therefore, compounded in a twin-screw co-rotating extruder by the use of specific additives: maleated and glycidyl methacrylate PLAs as compatibilizers/chain extenders and microlamellar talc as mineral filler/nucleation promoter. After pelletizing, the result- ing compounds were melt-processed by injection and compression molding. Differential scanning calorimetry, flexural tests in static machine and top-hat cylin- drical flat indentations were performed to evaluate the thermal and mechanical response of the molded components. The experimental findings show that crystalli- zation of the PLA can be controlled by fine-tuning the compound formulation as well as by properly setting the processing parameters. In addition, achievement of the appropriate crystallization degree in the polymer can lead to molded components, which exhibit improved mechanical strength and high thermal stability. KEYWORDS compostable polymer, mechanical response, melt processing, molding, thermal stability 1 | INTRODUCTION In the wide range of polymeric materials from renewable resources, the class of materials based on poly(lactic acid) (PLA) is a very promising alternative for the replacement of common plastics derived from petroleum, especially for applications in the rigid and flexible packaging industry. Although PLA is a biodegradable material with highly con- trollable compostability, its thermal and mechanical prop- erties make it hypothetically suitable for the production of durable goods, such as structural parts in cross-application (components and objects for the automotive, domestic, elec- tronic fields). However, several limitations have restricted the launch of a massive usage of PLA in industrial production, mainly due to the high-production cost of the raw material. In addition, the thermo-mechanical stability of PLA is not yet comparable to traditional noncompostable plastics that are extensively present on the market. On one hand, PLA shows the tendency to behave as an excessively rigid and/or brittle plastic, featuring too low toughness properties. On the other hand, PLA shows a mol- ten phase that is not thermally resistant during conventional