Improvement of thermal stability of UV curable pressure sensitive adhesive by surface modified silica nanoparticles

• Silica nanoparticles were modified to carry the vinyl groups for photo-crosslinking.
• Acrylic copolymer was modified to have the vinyl groups for photo-crosslinking.
• Strong and extensive interfacial bondings were formed between polymer and silica.
• Thermal stability of PSA was improved by forming nanocomposite with modified silica.

Pressure sensitive adhesives (PSAs) with higher thermal stability were successfully prepared by forming composite with the silica nanoparticles modified via reaction with 3-methacryloxypropyltrimethoxysilane. The acrylic copolymer was synthesized as a base resin for PSAs by solution polymerization of 2-EHA, EA, and AA with AIBN as an initiator. The acrylic copolymer was further modified with GMA to have the vinyl groups available for UV curing. The peel strength decreased with the increase of gel content which was dependent on both silica content and UV dose. Thermal stability of the composite PSAs was improved noticeably with increasing silica content and UV dose mainly due to the strong and extensive interfacial bonding between the organic polymer matrix and silica.