Surface morphology and property of UV-cured film containing photopolymerizable polysiloxane-based nanogels with initiating capability

We have synthesized a kind of photopolymerizable polysiloxane-based nanogel with intramolecular-initiating capability based on 4-hydroxybenzophenone (HBP), isobornyl methacrylate (IBMA), urethane dimethacrylate (UDMA) and 2-isocyanatoethyl methacrylate (IEM) and methacrylate-modified polysiloxane (PSMA). The nanogel possesses low migration of photolysis fragments and can dramatically reduce the volumetric shrinkage. In this work, the influences of the nanogels on the properties of UV-cured films prepared with nanogel and triethylene glycol dimethacrylate (TEGDMA) including rheology, glass transition temperature ( T g ), tensile property, thermostability, surface morphology and surface energy of the UV-cured films were systematically studied. The results show that with the addition of nanogels at different loading levels, the viscosity increased fast and reached up to 9600 mPa s. The increasing the content of nanogels in formulations resulted in the enhancement of thermal stability and elongation at break of the UV-cured films, and the formation of a more homogeneous network. Moreover, by adding the nanogels, the tensile strength of the cured films and surface energy declined. The enrichment of the nanogel on the surface can generate a more hydrophobic surface. Thus, the nanogels have potentially practical value in tuning structure and properties of polymer networks. Graphic abstract The polymerizable nanogels, which can initiate photopolymerization and reduce volumetric shrinkage, have the remarkable capability in decreasing surface energy, enhancing thermal stability and elongation at break, and homogenizing structure of polymer networks.