Modulating Chromium Containing Leather Wastes into Improved Composite Sheets Using Polydimethylsiloxane

Huge quantities of chrome-tanned leather wastes are produced every year from leather, footwear and clothing related industries. Many attempts have been made to reuse them in the form of boards, sheets, composites, etc. However, most of those methods have deficiencies such as low flexibility, cost effectiveness, non-eco-friendly, stringent process control and unacceptable properties. Our current work relies on an alternate method of reusing these wastes to form composite sheets with desirable characteristics. The waste chrome shavings were partially hydrolyzed and made into composite sheets using an eco-friendly polydimethylsiloxane (PDMS) polymer. The sheets were characterized for their mechanical, thermal and morphological properties. The tensile and thermal properties of composite sheets increase gradually upon increase in PDMS concentration up to 20 wt.% followed by an abrupt decrease when the PDMS concentration increased further to 30 and 40 wt.%. The softness of sheets has an inverse relationship with tensile stress and directly proportional to the elongation values. Fourier-transformed infrared (FTIR) analysis of composite sheets revealed the presence of dominant peaks corresponding to amide bands of collagen as well as characteristic bands of PDMS, showing the homogeneity of the developed composite sheets. Thus the developed composite sheets demonstrate potential for numerous applications in footwear, clothing and related industries.