Bamboo materials have a high cellulose content, slender fiber shape, good mechanical properties and plasticity. As a good alternative material for wood papermaking raw materials, bamboo can meet the pulp requirements for making medium and high-end paper. Studies have shown that bamboo chemical composition and fiber properties have good pulping properties. The performance of bamboo pulp is second only to coniferous wood pulp, and is better than broad-leaved wood pulp and grass pulp. Myanmar, India and other countries are at the forefront of the world in the field of bamboo pulping and papermaking. China's bamboo pulp and paper products are mainly imported from Myanmar and India. Vigorously developing the bamboo pulping and papermaking industry is of great significance to alleviating the current shortage of wood pulp raw materials.
Bamboo grows rapidly and can generally be harvested in 3 to 4 years. In addition, bamboo forests have a strong carbon fixation effect, making the economic, ecological and social benefits of the bamboo industry increasingly prominent. At present, China's bamboo pulp production technology and equipment have gradually matured, and main equipment such as shaving and pulping have been domestically produced. Large and medium-sized bamboo papermaking production lines have been industrialized and put into production in Guizhou, Sichuan and other places.
Chemical properties of bamboo
As a biomass material, bamboo has three major chemical components: cellulose, hemicellulose, and lignin, in addition to a small amount of pectin, starch, polysaccharides, and wax. By analyzing the chemical composition and characteristics of bamboo, we can understand the advantages and disadvantages of bamboo as a pulp and paper material.
1. Bamboo has a high cellulose content
Superior finished paper has high requirements for pulp raw materials, requiring the higher the cellulose content, the better, and the lower the content of lignin, polysaccharides and other extracts, the better. Yang Rendang et al. compared the main chemical components of biomass materials such as bamboo (Phyllostachys pubescens), masson pine, poplar, and wheat straw and found that the cellulose content was masson pine (51.20%), bamboo (45.50%), poplar (43.24%), and wheat straw (35.23%); the hemicellulose (pentosan) content was poplar (22.61%), bamboo (21.12%), wheat straw (19.30%), and masson pine (8.24%); the lignin content was bamboo (30.67%), masson pine (27.97%), poplar (17.10%), and wheat straw (11.93%). It can be seen that among the four comparative materials, bamboo is the pulping raw material second only to masson pine.
2. Bamboo fibers are longer and have a larger aspect ratio
The average length of bamboo fibers is 1.49~2.28 mm, the average diameter is 12.24~17.32 μm, and the aspect ratio is 122~165; the average wall thickness of the fiber is 3.90~5.25 μm, and the wall-to-cavity ratio is 4.20~7.50, which is a thick-walled fiber with a larger aspect ratio. Pulp materials mainly rely on cellulose from biomass materials. Good biofiber raw materials for papermaking require high cellulose content and low lignin content, which can not only increase the pulp yield, but also reduce ash and extracts. Bamboo has the characteristics of long fibers and large aspect ratio, which makes the fiber interweaving more times per unit area after bamboo pulp is made into paper, and the paper strength is better. Therefore, the pulping performance of bamboo is close to that of wood, and is stronger than other grass plants such as straw, wheat straw, and bagasse.
3. Bamboo fiber has high fiber strength
Bamboo cellulose is not only renewable, degradable, biocompatible, hydrophilic, and has excellent mechanical and heat resistance properties, but also has good mechanical properties. Some scholars conducted tensile tests on 12 types of bamboo fibers and found that their elastic modulus and tensile strength exceeded those of artificial fast-growing forest wood fibers. Wang et al. compared the tensile mechanical properties of four types of fibers: bamboo, kenaf, fir, and ramie. The results showed that the tensile modulus and strength of bamboo fiber were higher than those of the other three fiber materials.
4. Bamboo has a high ash and extract content
Compared with wood, bamboo has a higher ash content (about 1.0%) and 1% NAOH extract (about 30.0%), which will produce more impurities during the pulping process, which is not conducive to the discharge and wastewater treatment of the pulp and paper industry, and will increase the investment cost of some equipment.
At present, the quality of Yashi Paper's bamboo pulp paper products has reached the EU ROHS standard requirements, passed the EU AP (2002)-1, US FDA and other international food-grade standard tests, passed the FSC 100% forest certification, and is also the first company in Sichuan to obtain the China safety and healthy certification; at the same time, it has been sampled as a "quality supervision sampling qualified" product by the National Paper Products Inspection Center for ten consecutive years, and has also won honors such as "National Quality Stable Qualified Brand and Product" from the China Quality Tour.
Post time: Sep-03-2024
