Processes for enhancing flame retardance and chemical resistance of polymers

A method for preparing an injection-molded article having low yellowness and high chemical resistance, comprising:

• receiving a composition that comprises:
• a cross-linkable polycarbonate resin having endcaps derived from a monohydroxybenzophenone, a weight average molecular weight (Mw) from 15,000 to 30,000 and a PDI from 3.0 to 4.0 as measured by GPC using a UV detector and polycarbonate standards, and a monohydroxybenzophenone-derived endcap content from 3.0 to 4.5 wt %;
• optionally one or more additional polycarbonate base resins different from the cross-linkable polycarbonate resin;
• and
• optionally a flame retardant;
• wherein the composition has a melt flow rate (MFR) of 7 g/10 min or higher, measured at 300° C./1.2 kg/360 sec dwell;
• injection-molding the composition to a molded article;
• and
• exposing the molded article to a selected UV light range and a selected dosage of UV radiation to obtain the injection-molded article, wherein the injection molded article has a YI of 15 or less at 3.2 mm thickness when measured at least 48 hours after UV exposure, and has a % retention of 85% or greater at 3.2 mm thickness in a tensile elongation at break test using the ASTM D638 Type I method at 50 mm/min after exposure to acetone under 1.0% strain at 23° C.

A composition, comprising:

• a cross-linkable polycarbonate resin having endcaps derived from a monohydroxybenzophenone and a weight average molecular weight (Mw) from 15,000 to 30,000 and a PDI from 3.0 to 4.0 as measured by GPC using a UV detector and polycarbonate standards;
• optionally one or more additional polycarbonate base resins different from the cross-linkable polycarbonate resin;
• and
• a flame retardant;
• wherein the composition comprises at least 45 wt % of the cross-linkable polycarbonate resin, wherein the monohydroxybenzophenone-derived endcap content of the composition is between 1.2 wt % and 4 wt %, wherein the composition has a melt flow rate (MFR) of 7 to 20 g/10 min measured at 300° C./1.2 kg/360 sec dwell, and wherein an article formed from the composition has a % T of 85% or greater at 3.2 mm thickness.