On December 11, 2018, AAA revealed that clouded or yellowed headlights (Figure 1) generate only 20 percent of the amount of light that new headlights do, leading to dangerous nighttime driving conditions. This decrease is caused by sunlight damage to protective plastic coatings, resulting in discoloration that considerably diminishes the headlight’s ability to provide adequate light on dark roadways. With 50 percent of crashes occurring at night, AAA urges drivers to check their headlights for signs of deterioration and invest in new headlights or, at a minimum, a low-cost service to boost the safety of driving after dark.
Polycarbonate (PC) is attractive as an important transparent materials due to its high impact resistance, low density, high thermal stability, excellent optical properties and so on. Therefore, PC has been used widely from small-sized optical products such as compact discs and eyewear lenses, to large-sized transparencies such as aircraft canopy and automotive glazing. However, PC exhibits low hardness, poor abrasion resistance, and poor UV and solvent resistance, which limits its applications greatly.1 Figure 2 shows the simplified chemical structure of polycarbonate.