Strength from Within: Reversible Reinforcement of Paper through In-Sheet Formation of Thiol-Catechol Polymers.

Area of Science:

• Materials Science
• Polymer Chemistry
• Paper Engineering

Background:

• Mechanical integrity of paper is vital, but polymer reinforcement often leads to uneven coatings.
• Strong polymer-fiber interactions can hinder uniform deposition, limiting strengthening efficiency.

Purpose of the Study:

• To develop a method for uniform polymer deposition on cellulose fibers for enhanced paper strength.
• To investigate the efficacy of in-situ generated polymers with thiol-catechol-connectivities (TCC) for paper reinforcement.

Main Methods:

• Utilized in-sheet polymerization and adhesion (InSPA) to generate reinforcing polymers directly on cellulose fibers.
• Synthesized TCC polymers via a Michael-type polyaddition reaction between benzenedithiol isomers and bisquinone A.
• Investigated polymer loading, fiber penetration, and coating homogeneity.

Main Results:

• Achieved uniform polymer coatings with up to 48 wt.-% polymer loading.
• Demonstrated significant increases in paper strength: doubled dry tensile index and 7-fold increase in wet state.
• Maintained paper porosity despite high polymer loading and introduced hydrophobicity.

Conclusions:

• InSPA methodology effectively reinforces paper materials with homogeneous polymer coatings.
• TCC polymers enhance paper mechanical properties, making them suitable for oil/water separation membranes.
• The polymer coating is removable in a water-based process, enabling end-of-life recyclability.