PAPERmaking! g FROM THE PUBLISHERS OF PAPER TECHNOLOGY Volume 1, Number 1, 2015
Breaking Length The most important factors affecting the breaking length of paper are the number and quality of bondings between fibres (Testova 2006). Tensile strength directly shows a key aspect of the durability and final functionality of many products such as Banknote. According to the Figure 5, the breaking length decreased with the increase of CPAM level. Reduction of breaking length due to retention aids addition can be attributed, at least in part, to more absorption of Nanosilver and also increasing porosity or flocculated character of Banknote paper (Roberts et al 1986). By increasing of bonding involving the fibre- CPAM-silver combination, fibre-fibre bonding decreased, resulting in a considerable decline in breaking length. Also, weak formation and flock formation decreases the breaking length. As tensile strength decreased even without retention aids, much of the decrease can be attributed to Nanosilver as a major factor (Imani 2011).
Figure 5. Effect of CPAM and Nanosilver on breaking length of Banknote paper
Tear Strength Tear index depends on fibre length, individual fibre strength, and Relative Bonding Area (RBA). In the case of a sheet having low RBA, tear strength is more dependent on fibre- fibre bondings, whereas by increasing of bonding, individual fibre strength becomes crucial in tear index (Testova 2006). Tear index is one of the paper quality parameter that affects the runnability of a paper machine. As can be seen in Figure 6, tear index was decreased with increasing consumption of retention aid. This can be related to increased retention of fines as well as decreasing in average fibre length. On the other hand, the presence of Nanosilver between fibres will tend to reduce fibre bonding, leading to a decrease in tear strength. These results confirmed Ebrahimi’s report (2011), which indicated that by increasing filler retention on CMP fibre, tear strength was reduced. Folding Endurance This test involves a combination of tensile strength, elongation, flexibility, compatibility, shear stresses, and relative fibre length change (Erfani 2011). According to Figure 7, by
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Article 3 – Hygiene (nanosilver)
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