PMMA (polymethyl methacrylate), commonly known as plexiglass or acrylic, is a widely used polymer material. Its main characteristics are as follows:

一、Excellent optical performance

With a light transmittance exceeding 92%, close to that of natural quartz and far surpassing ordinary glass (approximately 85%), it provides soft light 

and clear vision.

Its refractive index is approximately 1.49, allowing some ultraviolet light to pass through (approximately 73% transmittance in the 200-400nm 

wavelength range), making it suitable for applications such as optical instruments and LED lighting.

二、Good mechanical properties

It exhibits high strength at room temperature, with tensile, flexural, and compressive strength superior to general-purpose plastics like polystyrene. 

However, its impact toughness is relatively low and requires modification to improve.

Its density is approximately 1.18-1.19 g/cm³, only half that of glass, making it lightweight and shatterproof. When broken, it does not produce sharp 

fragments, ensuring high safety.

It has relatively low surface hardness (Mohs hardness 2-3), making it prone to scratches, but this can be improved to above 4H through surface 

hardening treatment.

It possesses excellent weather resistance, resisting yellowing and embrittlement even after long-term outdoor use. It also exhibits strong resistance 

to UV radiation and ozone, making it suitable for applications such as architectural lighting and outdoor signage.

It has good thermal stability, with a decomposition temperature above 270℃ and a wide processing temperature range (160-270℃).

三、Good chemical stability

It is resistant to alkalis, dilute inorganic acids, water-soluble salts, oils, and aliphatic hydrocarbons, but not to ketones, chlorinated hydrocarbons, 

and aromatic hydrocarbons; contact with these solvents may cause it to dissolve or swell.

It has strong hygroscopicity (water absorption rate 0.3%-0.4%) and requires drying before processing; otherwise, it is prone to producing bubbles 

and affecting transparency.