Modification of elastollan by extrusion process for improved thermal, antimicrobial and biocompatible behavior

Thermoplastic polyurethanes (TPUs) posses an inherent structure morphology and their properties can be controlled by changing the composition and nature of blended materials. These are linear block copolymers; consisting of alternating soft and hard segments. This study was designed to prepare TPUs using extrusion process through incorporation of chitosan and curcumin. A series of biobased TPUs were synthesized using curcumin, chitosan and montmorillonite (MMT) clay and five different formulations were prepared by varying the percentage (w/w) ratio of chitosan and curcumin. The results demonstrated that the synergistic effect for incorporation of curcumin and chitosan has enhanced thermal stability and biocompatible behavior of the designed polyurethanes (PUs) formulations. Spectroscopic technique such as FTIR and 1HNMR revealed the synthesis of modified TPUs through hydrogen bonding between elastollan, chitosan, curcumin and nanoclay and a peak around 3300-3400 cm -1 confirmed that urethane linkage was developed among the constituents while scanning electron microscopy depicted the miscibility of curcumin and chitosan within TPUs by showing strong adhesion with the material surface of designed polyurethanes. Three phases of degradation were identified by thermogravimetric analysis, and the occurrence of these steps differed between the TPU frameworks depending on the contents of chitosan and curcumin. However, contact angle measurements demonstrated that curcumin imparted hydrophobic character (86.5 degrees) in comparison to the chitosan modified PUs. In vitro antimicrobial activity of modified thermoplastic polyurethanes against Escherichia coli and Bacillus Subtilis indicated that sample PUE3 exhibits more inhibition zone and it is suggested that its mode of action is bacteriostatic. More promisingly a key finding from hemolysis analysis represented that incorporation of chitosan and curcumin resultantly enhanced the blood compatibility and decreased the blood cell rapture. This remarkable property made them a potential candidate for biomedical application. Hence, it can be concluded that a novel set of biocompatible TPUs for biomedical applications could efficiently be developed through incorporation of curcumin and chitosan.