Kinetic Study of Different Tin‐Free Catalysts for an Efficient Synthesis of Bio‐Based Thermoplastic Polyurethanes

ABSTRACT Organotin‐based chemicals are utilized in the majority of applications; however, because of rising concerns about their toxicity, their use is being limited, and the demand for alternative catalysts is increasing. In this work, the Bio‐TPUs were successfully synthesized by the one‐step polymerization of 71% bio‐based 1,5‐pentamethylene diisocyanate (PDI), 100% corn extract‐based polyol poly trimethylene ether glycol (PO3G), 1,3 propanediol (PDO) as chain extender, and four tin‐free catalysts FeCl 3 , Fe(acac) 3 (Iron(III) acetylacetonate), Ti( i OPr) 2 (acac) 2 (Titanium isopropoxide acetylacetonate), and Mn(acac) 2 (Manganese(II) acetylacetonate) as catalysts for the synthesis of an innovative family of fully biobased thermoplastic polyurethane elastomers (Bio‐TPUs) with a mixing ratio of OH [diol]:NCO[isocyanate]:OH[extender] = 1:3:2. The effects of selected catalysts on the designs and characteristics of TPU polymers and networks are studied to optimize the catalyst‐property relationship for targeted application. Moreover, a kinetic analysis of the Bio‐TPUs was conducted using FeCl 3 , Fe(acac) 3 , Ti( i OPr) 2 (acac) 2 , and Mn(acac) 2 as catalysts. In situ FT‐IR was utilized to track the kinetics of the reactions at room temperature. Kinetic studies investigate the rate of the polymerization reaction. This includes determining how rapidly the reaction occurs under various conditions, such as changing the reaction time. Besides, we discussed the Bio‐TPU mechanism in the presence of FeCl 3 , Fe(acac) 3 , Ti( i OPr) 2 (acac) 2 , and Mn(acac) 2 catalysts. Finally, in silico docking simulations were used to determine the interaction between Bio‐TPU and the DNA Gyrase enzyme, and then the biocompatibility of TPU was confirmed from direct cell seeding experiments.