In recent years, the application of bamboo powder as filler for film‑bag materials has attracted widespread attention, with its application scenarios and consumption scale expanding rapidly.
What is Bamboo Powder?
Bamboo powder refers to the powdery substance obtained by physical processing including crushing, grinding and screening using bamboo as raw material, and it belongs to filling additives. Approximately 30 % of processing residues from bamboo can be converted into bamboo powder. As an important biomass filler, bamboo powder is widely used in daily‑use goods, agriculture, industrial excipients and other fields, delivering both environmental benefits and economic returns.
Bamboo powder mainly consists of organic components such as cellulose, lignin and hemicellulose, together with ash, protein, lipids, pectin and other substances. According to research conducted by Fujian Academy of Forestry Sciences, bamboo powder made from 3‑year‑old moso bamboo contains 37.3 % cellulose and 24.5 % lignin. China ranks first worldwide in bamboo species, planting area and output as a major bamboo‑producing country, making it urgent to develop innovative approaches for full‑value utilization of bamboo resources.
Key Properties of Bamboo Powder
Morphology: Bamboo powder particles generally exhibit an elongated fibrous shape, with an average length of 0.61 mm (mainly ranging from 0.1 mm to 0.7 mm) and an average width of 136 μm (mainly ranging from 20 μm to 220 μm). This indicates a high aspect ratio, enabling it to function as reinforcing fibers in composites.
Particle size and specific surface area: Bamboo powder is available from tens up to several hundred mesh. Finer particle size corresponds to larger specific surface area and greater contact area with matrix resin, which theoretically favours interfacial bonding. Nevertheless, excessively fine powder tends to agglomerate. Hence, physicochemical properties and application performance of bamboo powder are highly dependent on its particle‑size distribution.
Hydrophilicity: Rich in polar groups (hydroxyl, carboxyl, etc.), bamboo powder shows strong hydrophilicity. This intrinsically conflicts with most hydrophobic polymer matrices and constitutes a critical bottleneck restricting its broader application.
Thermal stability: The initial decomposition temperature of bamboo powder is around 200‑250 °C, the maximum decomposition rate occurs at 300‑350 °C, and its char residue ranges from 15 % to 25 %. Its thermal‑decomposition temperature is lower than the processing temperature of many melt‑processable polymers, posing challenges for its stability during high‑temperature processing.
Classification of Bamboo Powder
Featured by low‑carbon footprint, biodegradability and low cost, bamboo powder, a vital biomass filler, is widely adopted to develop plastic products for daily‑use articles, construction engineering, transportation and agriculture. Given that its physicochemical and functional performance strongly depends on particle‑size distribution, bamboo powder is divided into four major grades based on particle‑size profile and end‑use applications: coarse bamboo powder, fine bamboo powder, micro bamboo powder and ultrafine bamboo powder.
Coarse bamboo powder (millimetre scale): Derived from residues generated during rough planing, finish planing and stranding of standardized bamboo strips. It retains intact bamboo‑fiber structure with high moisture absorption yet poor flowability, mainly applied as filler for cat litter, animal feed, cement mortar and bakelite.
Fine bamboo powder (60 μm ≥ D90 > 30 μm): Produced by processing bamboo residues with a ring‑roller mill high‑speed pulverizer. It displays noticeable surface activity and markedly elevated specific surface area. Filled into biodegradable polyester, combined with injection moulding, vacuum forming and compression moulding, it can be manufactured into cutlery (knives, forks, spoons), coffee cups, seedling trays and seedling pots.
Micro bamboo powder (30 μm ≥ D90 > 10 μm): Manufactured by processing bamboo residues through a ring‑roller mill high‑speed pulverizer coupled with an air classifier. Within this particle‑size range, bamboo powder undergoes drastic functional changes with significantly enhanced hydrophilicity and adsorptive capacity. It serves as an ideal filler for biodegradable shopping bags, courier bags, refuse sacks, flat open bags, T‑shirt bags and nursery bags.
Ultrafine bamboo powder (D90 ≤10 μm): Produced by four‑stage tandem processing: ring‑roller milling → air classification → jet milling → secondary air classification. It possesses extremely high surface energy and nano‑material‑like properties, suitable for manufacturing biodegradable agricultural mulch films.
Performance Advantages of Bamboo Powder as Filler
Compared with other organic and inorganic fillers, bamboo powder presents distinct merits for film‑bag materials, mainly reflected in the following five aspects:
- Low tap density (tap‑density values for bamboo powder of 60 μm, 30 μm, 20 μm and 10 μm are 0.33 g/cm³, 0.26 g/cm³, 0.23 g/cm³ and 0.17 g/cm³ respectively), which effectively cuts logistics costs.
- High polysaccharide content and low ash content facilitate cross‑linking with polyester and improve mechanical performance of film‑bag materials.
- High starch content delivers good processing plasticity.
- Abundant pores and high permeability enable formation of stable interlocking structure with polyester matrix.
- Low processing cost without requirement for high‑end equipment or complex workflows.
dustrialization Status of Bamboo Powder Fillers
Driven by global plastic‑restriction policies and carbon‑neutrality goals, developing low‑cost, high‑performance bio‑based biodegradable materials has become a hot research topic in recent years. Bamboo‑powder‑filled film‑bag materials combine biodegradability, low cost and favourable mechanical properties and are widely used in daily‑use commodities, packaging, agricultural mulch films and other sectors.
Despite great development potential as filler for biodegradable plastics, bamboo powder features a relatively high glass‑transition temperature and poor thermoplastic processability. At present, when compounded with biodegradable polyesters, it mainly functions to lower product density and increase bio‑based content.
This article is reprinted from China Powder Network for study and reference only, and does not constitute any professional advice or commercial basis.
