Effect of contact time on the properties of cellulose, cellulose acetate and,ts film from various wastes

Abstract

In this research, the cellulose has been successfully extracted from different type of wastes such as paper waste (empty tissue roll (ETR) & egg tray (ET) and fruit waste (jack fruit rind (JR)). From the extracted cellulose, the cellulose had been modified to Cellulose Acetate (CA). Modification of cellulose to CA involved acetylation process that used sulphuric acid (H2SO4) as catalyst. FTIR results showed that some of the peak disappeared after extraction process at certain wavelength (1700 - 1600 cm-1, ~1500 cm-1). The intensity of few peaks at 3500 - 3000 cm-1 and 3000 - 2800 cm-1 also decreased after extraction process. All samples (ETR, ET and JR) for CA24 exhibit lowest intensity compared to other contact time. This might be due to the increasing of acetyl group in cellulose backbone and hydrophobicity of the film. This is due to the removal of certain compounds such as lignin and hemicellulose in all raw sample. The effect of contact time (1 to 24 hours) to the acetyl content and degree of substitution (DS) had been studied. It found that, for all wastes exhibited high acetyl content and high of degree of substitution when the contact was 24 hours. In mechanical properties, all CA24 film exhibit slightly higher tensile strain compare to cellulose film for both samples (ET, ETR and JR). Young's Modulus and tensile stress for CA24 film is also higher compare to cellulose film. This is due to the elimination of OH-groups which reduce the water sensitivity of cellulose and due to the internal plasticization of CH3CO- groups. Moreover, acetylation process increase the mechanical properties of the film produced. It can also be seen that Young's modulus increase with increase in CA contact time. This is expected, as addition of CA give a dense structure to film resulting in higher modulus values than porous structure. CA-24 film has the lowest moisture uptake. This is because CA-24 has lower OH- group presence in it. Therefore, ca-24 film shows better hydrophobicity. CA-24 film has lowest solubility most likely due to the replacement of OH- groups to CH3CO- groups. The replacement of OH- groups in cellulose with CH3CO- groups reduced its solubility in water but enhance its solubility in organic solvents. DSC results revealed that the CA24 for all samples (ETRP, ETR and JR) exhibit low Tg. This is due to the fact that, the increasing of contact of time, will increase the number of acetyl group. Hence, when the number of acetyl group increased, the hydrophobicity of the film also increased. Therefore, the ability of CA to form hydrogen bonding with water molecules also decrease. Hence, the segmental molecular ability increase due to the decreasing of hydrogen bonding in CA film.