Modified natural material and use thereof

The invention changes the chemical structure parameters of the starch by introducing specific modifying groups (long-chain alkyl groups with 12-40 carbon atoms, aryl groups with 6-20 carbon atoms, or polysiloxane groups) directly onto the starch molecule. This structural modification inherently provides oil resistance without requiring pH adjustment or complex composition control, as the hydrophobic modifying groups directly interact with oil molecules to prevent penetration.

The invention creates a composite material by chemically bonding hydrophobic modifying groups (fatty acid groups, aromatic groups, or polysiloxane groups) to the starch backbone. This composite structure combines the biodegradability and film-forming properties of starch with the oil-repelling properties of the modifying groups, achieving effective oil resistance without the need for additional pH adjustment agents or complex mixing processes.

The invention modifies the degree of substitution and the type of modifying groups on the starch molecule to achieve the desired balance between performance and biodegradability. By controlling the substitution degree (partial rather than complete substitution) and selecting biocompatible modifying groups, the material maintains oil, water, and heat resistance while preserving biodegradability and environmental friendliness.

The invention uses starch, a renewable and biodegradable resource, as the base material instead of petroleum-based cellulose acetate. The modified starch provides sufficient durability for food container applications while being fully biodegradable, aligning with the trend toward disposable, environmentally friendly packaging solutions that do not persist in the environment.