Effects of Phenyl Hydrogen Polysiloxane Molecular Structure on the Performance of LED Packaging Silicone Rubber

Phenyl hydrogen polysiloxanes of different structures were prepared, and LED packaging silicone rubbers were made from these polysiloxanes. The hardness, elongation, tensile strength and anti-yellowing of the LED packaging silicone rubbers on lamps were characterized. The results show that phenyl hydrogen polysiloxanes of resin structures had lower molecular weight, and that the cured silicone rubbers exhibited higher hardness, tensile strength, crosslink density and lower gas permeability. Phenyl hydrogen polysiloxanes of oil structures had higher molecular weight, and the cured silicone rubbers from these polysiloxanes exhibited lower volume expansion coefficient, higher hot and cold impact cycles and less change in hardness during the aging process. The study results further showed that the degree of change in hardness, yellowing, gas permeability, sulfuration and volume expansion coefficient was reduced by using phenyl hydrogen polysiloxanes of resin-oil structures as crosslinking agents, enabling the combined performance advantages of both resin-structure and oil-structure rubbers. DOI: http://dx.doi.org/10.5755/j01.ms.24.2.18494