Preparation and physical properties of transparent foldable poly(methyl methacrylate) based materials using reactive poly(vinyl butyral)

The aim of this study is to prepare transparent foldable poly(methyl methacrylate) (PMMA) based materials by using poly(vinyl butyral) (PVB) with polymerizable group. The influences of PVB content, modification of OH group in PVB, concentration of polymerizable groups, and molecular weight of PVB on the foldability and physical properties such as transparency, mechanical properties, surface hardness of the resulting PVB/PMMA graft copolymers were investigated. The increase of PVB content contributed to the improvement of the folding property but surface hardness was decreased. The introduction of the polymerizable group to the OH group of PVB and the increase of the concentration improved the surface hardness and suppressed the whitening of bent surface. Furthermore, by using PVB having a polymerizable groups, PVB and PMMA were dispersed so finely that the interface cannot be confirmed clearly, and samples containing 10 wt% or more of PVB with a polymerizable groups were foldable and maintained similar mechanical properties and transparency as PMMA. The use of high molecular weight PVB with polymerizable groups promoted the formation of fine phase separated structures, enabled bending at a lower PVB content.