Preparation and Performance of Poly(butyl fumarate)-Based Material for Potential Application in LED Encapsulation

A UV-curable poly(butyl fumarate) (PBF)/poly(propylene fumarate)-diacrylate (PPF-DA) hybrid material with good performance for LED encapsulation is introduced in the paper. They have been prepared by radical polymerization using PBF and PPF-DA macromers with a UV curing system. PBF and PPF-DA were characterized by Fourier-transform infrared (FT-IR) and H-nuclear magnetic resonance (H-1 NMR). The thermal behavior, optical and mechanical properties of the material were examined by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), ultraviolet-visible spectroscopy (UV-vis), and a material testing system mechanical testing machine, respectively. The results indicated that the hybrid material has a suitable refractive index (n = 1.537) and high transmittance (99.64% in visible range) before/after thermal aging. With the increasing of the double bond ratio from 0.5 to 2, the water absorption ratios of the prepared encapsulation material were 1.22%, 1.87% and 2.88%, respectively. The mechanical property experiments showed that bonding strength was in the range of 1.86-3.40 MPa, tensile-shear strength ranged from 0.84 MPa to 1.57 MPa, and compression strength was in the range of 5.10-27.65 MPa. The cured PBF/PPF-DA hybrid material can be used as a light-emitting diode (LED) encapsulant, owing to its suitable refractive index, high transparency, excellent thermal stability, lower water absorption, and good mechanical properties.