Transforming Chromium Containing Collagen Wastes Into Flexible Composite Sheets Using Cellulose Derivatives: Structural, Thermal, and Mechanical Investigations

Leather, footwear, and clothing industries produce significant quantity of chromium containing proteinaceous wastes. One of the major uses of these wastes is to convert them into sheets or boards. However, the previous methods could not provide flexible sheets with desired strength. Here, we describe a simple and efficient method for the preparation of flexible composite sheets using chromium containing collagenous wastes (CS) with the use of cellulose derivatives. The leather wastes have been partially hydrolyzed and converted into composite sheets under microwaves with the addition of 2-hydroxyethyl cellulose (HEC) in varying concentrations from 2.5 to 20 wt%. A comprehensive strength as high as 3.14 +/- 0.45 MPa with a softness of 3.8 +/- 0.2 mm is achieved with the addition of 20 wt% HEC in the CS/HEC composite sheets. Scanning electron microscopic and mercury intrusion porosimetric analysis demonstrate the reduction in pores, especially micro pores (< 50 mu m), when the concentration of HEC is higher thereby showing improved interfacial adhesion of HEC onto CS. Infrared spectroscopy result indicates the presence of distinctive bands associated with both CS and HEC. There is also a reasonable increase in the thermal stability of the CS/HEC sheets as the content of HEC increases. Hence, the developed CS/HEC composite sheets were found to be flexible and have improved thermo-mechanical properties, which are suitable for applications in leather product and allied industries. POLYM. COMPOS., 32:1009-1017, 2011. (C) 2011 Society of Plastics Engineers