The papermakers must have a well-founded reason for using starch globally in ancient days, today and, very probable, tomorrow as well. These specialists in their areas understand what performance level their products have been looking for. Or more specific: what are the unwanted characteristics in the final grade of paper or board in question. But there are many secrets as well for using the starch in making the paper strong. A key problem throughout papermaking history was physical strength measured by multiple means and devices and displayed in more or less descriptive parameters.
So how does it come? Why would that matter so much? From the point of view of consumers, perhaps from the likes of me or you in our daily lives, it is important that the product displays sufficiently strong fiber-to-fiber bonding. Starch and PVA are the most commonly textile sizing chemicals. However, for specific purposes, other size materials were developed and used. Carboxymethyl cellulose (CMC) is made from pulp of wood and lint of cotton and has a good cotton adhesion. The deal is with hydrogen bonds from the studies and peeks at the sub-fibre level. And the amount per physical contact region is more accurate. This translates into the Smartphone or HD-Led TV that you ordered last week arriving in your living room safe and sound because the packaging box was able to withstand the physical stress during transport without fail.
- Usage – Another instance is toilet paper that should last for a particular moment in its “wet-end implementation” before ending up in the sewer piping as distinct fibers as not to block them. Failure to meet the designed end-consumer criteria today usually involves additional issues and costs of some kind.
- Bonding- The papermaker washed the fiber suspension throughout the moment to create a constant moist web for pressing and eventually drying into a 2D paper structure. Various means can be implemented in order to attain an adequate amount of bonding between the fibers, i.e. to boost strength.
- Enhances strength – Normally, the circular, oblong fibers are beaten to become slightly flatter as well as’ hairy’ when fines are released. You can add some 5-15 kg well-cooked wet-end starch per ton fiber (dry / dry) to the papermaking furnish to boost the hydrogen bonding levels. This wet-end starch–known as internal sizing–works as a “bio glue” between cellulosic fibers to increase physical strength. Another approach is to add a continuously thin layer of starch to the solid paper web to enhance surface strength, aka surface size.
In a mill of this size, the mechanical modification path alone towards paper strength will not operate long. It is necessary to involve the paper chemistry path towards the same objective. The reason for starch being a key element of papermaking lies in its worldwide accessibility, simplicity in technology, and favorable economy. The two most common biopolymers are starch and cellulose. It can be done by applying cationic starches for greater fiber-fiber bonding. This universal green bonding agent provides physical, interfacial and chemical strength.