Messi Biology states that in daily life, common items such as spectacle lenses, cigarette filters, film substrates, and even some food packaging rely on cellulose acetate as a core raw material. This polymer material, obtained by the acetylation of natural cellulose, combines environmental friendliness with excellent processing properties. However, it also has limitations, such as insufficient heat resistance and limited stability. Magnesium oxide (MgO), a seemingly ordinary inorganic compound, acts as a “functional partner” for cellulose acetate, improving its comprehensive performance from multiple dimensions and expanding its application boundaries.
First, Magnesium Oxide is an excellent thermal stabilizer in the cellulose acetate system.
During high-temperature processing or long-term use, the acetyl groups on the cellulose acetate molecular chains are prone to hydrolytic cleavage. This leads to yellowing and brittleness of the material, causing a significant decline in mechanical properties. Since magnesium oxide is weakly alkaline, it can neutralize the trace amounts of acetic acid produced by the hydrolysis of cellulose acetate, preventing acidic substances from continuously damaging the molecular chains. It acts like a layer of “anti-corrosion armor” for the material. Experimental data shows that adding an appropriate amount of magnesium oxide can increase the thermal decomposition temperature of cellulose acetate by 20-30°C. This significantly enhances stability during high-temperature processing steps such as injection molding and extrusion, effectively reducing the defect rate during production.
Secondly, Magnesium Oxide can improve the mechanical properties of cellulose acetate.
Pure cellulose acetate has relatively limited toughness and impact resistance, which restricts its application in high-strength products. Magnesium oxide particles, characterized by their fine particle size and good dispersion, can form “reinforcement nodes” within the cellulose acetate matrix. When the material is subjected to external impact, these particles can disperse stress and hinder crack propagation, thereby increasing the tensile strength and bending resistance of the material. For example, in the production of spectacle lenses, cellulose acetate lenses containing magnesium oxide not only maintain their light transmittance but also see an increase in impact resistance by over 30%, greatly extending the service life of the lenses.
Furthermore, Magnesium Oxide endows cellulose acetate with flame retardant and antibacterial properties.
Cellulose acetate itself is somewhat flammable. The high melting point and thermal inertia of magnesium oxide allow it to form a dense char layer during combustion, which isolates oxygen and blocks heat transfer, playing a role in flame retardancy and smoke suppression. This enables the material to be used in packaging and construction materials where fire resistance is required. Simultaneously, the trace magnesium ions released by magnesium oxide can destroy the cell membrane structure of microorganisms, showing a significant inhibitory effect on bacteria such as Escherichia coli and Staphylococcus aureus. This makes the application of cellulose acetate in fields like food contact materials and medical consumables safer.
However, the addition amount of Magnesium Oxide must be strictly controlled.
Excessive addition can lead to a decrease in light transmittance and increased difficulty in molding. With the development of materials science, modified magnesium oxide (such as magnesium oxide surface-coated with organic groups) is further improving compatibility with cellulose acetate. This allows this pair of “partners” to exert a superior synergistic effect, providing new possibilities for the upgrading and generation renewal of cellulose acetate materials.