Introduction: The impact of paper strength of the raw material factors are the length of the fiber and fiber bonding, when the raw materials used to determine down, the bonding force between the fibers becomes the main factor to be considered, this short article will do a simple analysis of the factors affecting the bonding force.
Of course, the bonding force is also related to a series of factors in the operation of the paper machine, this small article mainly from the fiber itself to make a brief analysis.
The effect of pulping on fibers, especially the degree of fiber splitting and brooming, is the main factor affecting fiber binding, since both the external surface area of fibers and the number of hydrogen bonds are related to pulping.
At the same time, the size of fiber binding is related to the chemical composition and physical properties of the fiber as well as the tissue arrangement of the fiber.
That is to say, the lignin, hemicellulose and cellulose content of the fiber also affect the fiber bonding to some extent.
- The influence of the type of slurry
Different kinds of pulp, both in the physical structure, or chemical composition is not the same, generally speaking, chemical wood pulp fiber binding force is the largest, cotton pulp is the next, mechanical wood pulp is the worst.
- Effect of hemicellulose
Pulp with high hemicellulose content is easy to absorb water and swell when pulping, which increases the specific surface area and bonding area of fibers and improves the fiber bonding force.
The molecular chain of hemicellulose is shorter than cellulose and more hydrophilic, so it is easy to absorb water and swell and fine fiber when pulping, so the pulp containing more hemicellulose is easier to pulping, and the bonding force between fibers is also greater.
Of course, the hemicellulose content is too high, the pulp and paper are unfavorable, mainly because the hemicellulose absorbing swelling too fast, the pulp is too high, copied into the paper transparent and brittle, low strength.
On the other hand, more hemicellulose, more short fibers, the fiber itself will reduce the strength, while reducing the fiber bonding force
- Effect of cellulose
Generally speaking, the cellulose molecular chain is long, its polymerization is high, the fiber itself is strong, and it is not very easy to cut off when pulping, thus when it is cut to the proper length, the fiber has obtained sufficient filament broom, and the bonding force between fibers is larger.
- Effect of lignin
Lignin is mainly distributed in the outer layer of the primary and secondary walls of the fiber, due to the extremely low hydrophilicity of lignin, the presence of lignin affects the swelling of the fiber, fine fibrillation, and therefore the pulp containing more lignin, not easy to pulping, poor fiber bonding.
- The effect of paper additive
The addition of hydrophilic substances in the pulp, such as starch, protein, vegetable gum, etc. will increase the inter-fiber bonding force, which is because these substances themselves also have the same polar hydroxyl group as cellulose, due to the hydroxyl group through the hydrogen bonding bond, compared to the simple fiber to fiber bonding more firmly.
The addition of hydrophobic substances in the pulp, such as inorganic fillers and alum, will reduce the inter-fiber bonding force. This is because the addition of these substances will separate the fibers from each other and reduce the inter-fiber contact surface, thus affecting the fiber bonding force.