SYNTHESIS OF NOVEL UV-LIGHT CURABLE SHAPE-MEMORY POLYURETHANES

Abstract

. Polyurethanes (PU) are one of the most studied materials due to their high mechanical performance, flexibility and shape-memory ability. When compared to other homopolymer elastomers, polyurethane displays superior toughness and tear resistance due to the inhomogeneity of its microstructural composition. When both soft and hard segments are used in conjunction, it is possible for the elastic matrix to achieve the appropriate modulus and deformation ability by varying the ratio between them. In this article, novel polyurethane materials with pendant stearyl side chains having shape-memory characteristics were synthesized by the UV-light curing process for the first time. The influence of the amount of cross-linkers produced during the polymerizations between aliphatic urethane acrylate (aUA) and stearyl acrylate (SA) under UV light treatment using 2,2-dimethoxyl-2-phenyl acetophenone (DMPA) as photoinitator was investigated. The goal of this research is to combine mechanical strength with sharp memory capabilities in polymeric materials using the above–mentioned unique PU network structure design. The shape recovery rate (Rr), shape retention rate (Rf), tensile strength deformation and reflection-Fourier transform infrared (ATR, FT-IR) were used for characterizing the synthesized materials. The results indicated that a sufficient quantity of SA in the structure (30 wt.%) lead to a nearly 100 percent improvement in shape recovery capacity but slightly decreased the mechanical characteristics of the materials.