Photopolymer Resins from Sulfenyl Chloride Commodity Chemicals for Plastic Optics, Photopatterning and 3D-Printing

The development of a low-cost photopolymer resin to fabricate optical glass of high refractive index for plastic optics is reported. This new free radically polymerizable photopolymer resin, termed, disulfide methacrylate resin (DSMR) is synthesized by the direct addition of allyl methacrylate to a commodity sulfur petrochemical, sulfur monochloride (S₂Cl₂). The rapid rates of free radical photopolymerization confer significant advantages in preparing high-quality, bulk optical glass. The low-cost, optical glass produced from this photopolymer possesses a desirable combination of high refractive index (n ≈ 1.57-1.59), low birefringence (Δn < 10^-4), high glass transition values (T_g ≈ 100 °C), along with optical transparency rivaling, or exceeding that of poly(methyl methacrylate) (PMMA) as indicated by very low optical absorption coefficients (α < 0.05 cm^-1 at 1310 nm) measured for thick glass DSMR photopolymer samples (diameter (D) = 25 mm; thickness = 1-30 mm). The versatile manufacturability of DSMR photopolymers for both molding and diamond turn machining methods is demonstrated to prepare precision optics and nano-micropatterned arrays. Finally, large-scale 3D printing vat photopolymerization of DSMR using high-area rapid printing digital light processing additive manufacturing is demonstrated.