Restoring clarity in recycled polycarbonate demands precise management of material purity, thermal exposure, and mechanical stress

Polycarbonate is valued for its clarity and strength, but when recycled, it often loses some of its optical properties due to thermal degradation, mechanical stress, and the presence of impurities

To restore and maintain high transparency, the first step is sourcing clean, sorted feedstock

Use only transparent, unmarked PC components—eliminate all stickers, glue residues, and mixed plastic contaminants

Advanced near-infrared (NIR) sorting systems significantly improve separation accuracy

After collection, rigorous cleaning is non-negotiable for optical restoration

A high-pressure hot water rinse combined with industrial-grade detergents effectively strips away grime and lubricants

After washing, the flakes should be dried completely to prevent moisture from causing hydrolysis during melting, which leads to cloudiness and reduced molecular weight

Drying at temperatures around 120 to 130 degrees Celsius for several hours is recommended

Processing parameters are critical

The extrusion or injection molding temperature must be carefully controlled

Exceeding 300 degrees Celsius can cause thermal degradation, leading to yellowing and loss of clarity

Using a screw design that minimizes shear stress helps prevent mechanical degradation

A narrow processing window with precise temperature control ensures consistent melt flow without overheating

Stabilizer packages tailored for PC recycling preserve molecular weight and optical integrity

These additives reduce oxidative degradation and maintain molecular integrity, preserving transparency

Optical enhancers must be UV-stable and compatible with PC to prevent yellowing or fluorescence drift

Thermal relaxation after forming improves molecular alignment and optical homogeneity

Rapid quenching induces internal tension that scatters light

Finally, filtering the molten polymer through fine screens or melt filters removes any remaining particulates that could create haze

Real-time spectrophotometric feedback enables immediate process correction

A holistic approach to recycling enables optical performance indistinguishable from new polycarbonate

making it suitable for demanding applications like lenses, اکسیر پلیمر medical devices, and transparent enclosures