Synthesis and evaluation of novel aromatic acrylic monomers for optically clear adhesive with high refractive index

Abstract

Conventional optical polymers have low refractive index; (RI <1.5) which limit their usage in the field of optoelectronics. Therefore, two types of aromatic monomers with high RI value were developed; that is, ionic monomer (PA.HEMA.NEt3.H+) with RI = 1.5150 and monomer (PA.BA.GMA) with RI = 1.5403. The monomers were then individually combined with a newly synthesized oligomer based on phthalic anhydride epoxy acrylate; that is, (EA.PA) with RI = 1.5567. The structures of the synthesized monomers and oligomer were confirmed by NMR and FTIR spectroscopy and the chemical titration of the structure end groups. Different combinations of the monomers with oligomer EA.PA were examined to develop a UV‐curing adhesive with appropriate viscosity. According to TGA and DMTA test results, the composition containing oligomer EA.PA showed improved thermal degradation stability and high glass transition temperature. The lap shear adhesion test showed positive effect of oligomer EA.PA and PA.BA.GMA with an adhesion strength of up to 1.2 MPa. The RI value of the composition containing PA.BA.GMA and oligomer EA.PA was measured as 1.55 which is qualified for the most applications in optoelectronic. The improvement in RI value may be well attributed to the presence of aromatic rings in the polymer chain backbone. The high degree of aromaticity is in favor with the improved thermal stability in adhesive composition.

Optical and physical properties of zirconium dioxide reinforced poly(methyl methacrylate) nanocomposite films

“…Merrat et al prepared PMMA nanocomposites with graphitic carbon nitride, which was used for optoelectronic applications, mainly optical limiting 7 . Roghayeh et al, prepared high refractive index optical adhesive using aromatic acrylic monomers, in which the RI was measured to be 1.55 8 . Inshad et al made nanocomposite of polyaniline, camphor sulfonic acid, and PMMA with nickel nanoparticles which was used for optical filter application 9 .…”