Enabling Design of Strong and Tough Poly(Propylene Carbonate) Through In Situ Generated Poly(Propylene Carbonate)‐Based Cross‐Linked Microdomains

ABSTRACT The wide use of poly(propylene carbonate) (PPC), a biodegradable polymer made from carbon dioxide, will contribute greatly to alleviating environmental issues such as white pollution and greenhouse effect. However, the poor mechanical properties and low glass transition temperature (T g ) seriously limit the practical application of PPC. Traditional reinforcement methods for PPC will reduce the toughness sharply. Herein, we propose a new strategy for preparing strong and tough PPC through in situ generated high‐performance PPC‐based cross‐linked microdomains (PPC‐MD). Specifically, based on the aminolysis reaction between carbonate groups in PPC and multiple amine groups in polyethylenimine, PPC‐MD and hydroxy‐terminated PPC with low molecular weight (l‐PPC‐OH) are generated during melt blending. Then, hexamethylene diisocyanate is added to link l‐PPC‐OH for the purpose of eliminating the plasticization of l‐PPC‐OH and the degradation effect of terminal hydroxyl group. The PPC‐MD with high T g can effectively reinforce PPC and improve its toughness. The PPC/PEI/HDI‐0.02/0.04 shows a high tensile strength of 29.4 ± 2.5 MPa and a toughness of 86.8 ± 5.2 MJ/m 3 , which is 2.58‐ and 1.38‐folds of PPC, respectively. Besides, the PPC‐MD can greatly improve the T g of PPC as well. It is worth highlighting that this method can be accomplished by melt blending, which is facile and can be scaled up. We envision that this work will enrich the modification method of PPC and promote the practical application of PPC as the as‐fabricated PPC shows integrated high strength, high toughness, and high T g .