Impact of Beating on Tensile and Burst Strength of Paper Pulp Tray
Beating not only causes the surface of fibers to undergo fibrillation, but also generates finer fibers, which can enhance the retention of chemical additives by 15%. Additionally, it leads to tighter bonding between fibers, thereby increasing the physical strength of the paper, including wet strength from 152 to 541. However, excessive beating can affect the filtration and forming time of products, resulting in reduced production efficiency. In this experiment, only mild beating was carried out. After the beating experiment, the pulp was molded using a pulp molding equipment to prepare samples, which were then subjected to relevant tensile and burst strength tests.
Pic 1: The effect of beating of the bamboo pulp on tensile and burst strength
The tensile index and burst index were relatively small, measuring 7.5 N·m/g and 1.24 kPa·m²/g, respectively. After mild beating, both the tensile index and burst index of the products showed a significant increase, indicating that beating has a significant impact on the tensile strength and burst strength of high-quality industrial packaging pulp molded products. When the beating degree was increased to 20 “SR, the tensile index of the products rapidly rose to 27.4 N·m/g, and the burst index increased to 2.09 kPa·m²/g. This is because, in the initial stage of beating, fiber swelling and fibrillation occur at a faster rate, and the bonding between fibers also increases quickly. When the beating degree continued to increase to 30 “SR, the tensile index reached its maximum value of 43.8 N·m/g, while the burst index reached its highest value of 3.26 kPa·m²/g at 35 “SR. Subsequently, as the beating degree was further increased, the tensile and burst indexes of the pulp molded products began to decrease. This may be due to the fact that with the progress of beating, the degree of fibrillation on the fiber surface has reached a sufficient level, and the bonding area between fibers tends to stabilize, reaching the maximum point of fiber bonding strength. Further beating causes a significant reduction in fiber length, which becomes the primary factor affecting the strength of the products. At this point, the impact of fiber length outweighs the fiber bonding, leading to a decrease in product strength. In general, under conditions where the beating degree is not high, beating greatly improves the strength of the products compared to those without beating.
Influence of Bagasse Pulp Addition on Strength Performance of Paper Pulp Tray
Bagasse pulp (22.0°SR) was added to bamboo pulp (15.0°SR) in a certain proportion, and after mixing the two pulps evenly (17.9°SR), they were used to prepare samples of high-quality industrial packaging paper pulp molded products. The effect of bagasse pulp addition on the tensile strength and burst resistance of high-quality industrial packaging paper pulp molded products was studied.
The main factors influencing the tensile strength are the bonding force between fibers and the strength of the fibers themselves. In addition to being influenced by the bonding force and average fiber length, the burst resistance is also affected by the arrangement and interweaving of the fibers. It can be seen that when 100% bamboo pulp was used, the tensile index and burst index of the high-quality industrial packaging paper pulp molded products were relatively small, at 7.93 N·m/g and 1.19 kPa·m²/g, respectively. With the increase in the amount of bagasse pulp added, the tensile index and burst index of the products increased rapidly. When the addition amount of bagasse pulp reached 20%, the indices of the products reached their optimum values, increasing by 91.68% and 36.97%, respectively, compared to the pulp molded products using 100% bamboo pulp. This is closely related to the inherent characteristics of bamboo pulp fibers. Bamboo pulp fibers are relatively long and slender. Although the fibers can interweave with each other to form a fiber network during the filtration and forming process of high-quality industrial packaging paper pulp molded products, there are relatively large gaps between the fibers, resulting in the loss of a large portion of fine fibers. Therefore, the overall strength of the fiber network is insufficient, making it prone to damage or deformation. Although the fibers of bagasse pulp are shorter, they are thicker, and individual fibers have stronger load-bearing capacity. After being added to bamboo pulp fibers, the bonding force between fibers is strengthened, resulting in a better effect compared to using bamboo pulp alone. However, if bagasse pulp is continuously added, the tensile and burst resistance of the products start to decrease, albeit at a slower rate. This is because the fibers of bagasse pulp are shorter and without the protection of the long and slender bamboo pulp fiber network skeleton, the fine components are easily lost, leading to a decrease in strength performance.