Chitosan-Modified Talc: Improving Filler Performance in Papermaking
Fillers are widely used in papermaking to reduce fiber consumption and improve paper properties. Among them, talc is one of the most common mineral fillers due to its stability and ability to improve opacity, smoothness, and drainage.
However, when filler loading increases, several issues may arise, including reduced paper strength, lower filler retention, sizing difficulties, and dusting. To address these challenges, surface modification of fillers has become an important approach.
One promising solution is chitosan-modified talc.
Chitosan is a natural polysaccharide containing abundant hydroxyl and amino groups, which can form hydrogen bonds with cellulose fibers. When deposited on talc particles, it creates a thin polymer layer that improves the bonding between fillers and paper fibers, enhancing both retention and strength.
Simplified Preparation Process
1️⃣ Talc suspension
Disperse talc in water to form a slurry.
Talc content: 5–15%
2️⃣ Chitosan solution
Dissolve chitosan (viscosity 30–950 cps) in dilute acetic acid.
Concentration: 2–7 g/L
3️⃣ Adsorption mixing
Add the chitosan solution to the talc slurry and stir.
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Stirring: 300–1100 rpm
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Time: 5–100 min
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Chitosan solution: 1–11% of total mixture
4️⃣ pH adjustment
Slowly add 5% NaOH to adjust the pH to 6–14, allowing chitosan to precipitate and form a dense coating layer on talc particles.
Benefits
Using chitosan-modified talc can help:
✔ Improve filler retention
✔ Maintain paper strength at higher filler loading
✔ Reduce dusting and linting
✔ Expand the application potential of talc in papermaking
Combining mineral fillers with bio-based polymers such as chitosan provides a practical way to enhance both paper performance and production efficiency.
💬 How do you improve filler retention in your papermaking process?
