What is the reason for the opacity of the black acrylic sheet? How to solve it?

Black acrylic is opaque. Black acrylic because it is a solid color, solid color means opaque. Translucent is not called solid color. The black acrylic sheet is opaque, it is black when it is not illuminated during the day, and it is white when the LED light is on at night.
Acrylic, also known as PMMA or Acrylic, is derived from English acrylic (acrylic plastic). The chemical name is polymethyl methacrylate. It is an important plastic polymer material developed earlier. It has good transparency, chemical stability and weather resistance, easy dyeing, easy processing and beautiful appearance. It is used in the construction industry. Has a wide range of applications. Plexiglass products can generally be divided into cast sheets, extruded sheets and molding compounds.