Preparation of Thermo‐Responsive Smart and Shrinkable Bio‐Composite Using Sugarcane Waste and Sustainable Polyurethane

Abstract

Smart materials that respond to external stimuli are useful for applications ranging from artificial skin to sensing to cosmetics. Inspired by natural phenomena (self‐healing, shape memory, and shrinking), this work develops a novel smart bio‐composite using sustainable polyurethane (PU) and sugarcane bagasse (SB) waste without using a solvent. PU is synthesized using polycaprolactone (PCL) diol, castor oil (CO) as a polyol, and isophorone diisocyanate (IPDI) as diisocyanate. Composites are prepared using PU and SB in the presence and absence of poly(acrylic acid) (PAA) and are denoted as PBA and PB, respectively. TGA and DSC analysis indicate the broad (−68.4 °C to 192 °C) thermal stability of these materials. PBA and PB composites exhibited relatively fast (20–30 min) self‐healing and high shape fixity ratio (Rf) (70–83%), and shape recovery ratio (Rr) (82–100%) at 60 °C in the air. Furthermore, PBA shows hot water‐responsive rapid 100% shape recovery and also exhibits thermoresponsive shrinkage properties like human skin. PBA lifts a material 13.3±2 % of its original length by utilizing its thermoresponsive shrinking property. These inexpensive materials with self‐healing, shape recovery, high thermal stability, and thermo‐responsive properties are attractive and may be useful in artificial skin, sensor, and coating applications.