History 

The development of acrylic started with the discovery of methyl methacrylate (MMA) in the 1870s by Henri Moreau, a French chemist. It was only four decades later that British scientists at Imperial Chemical Industries and German chemists working for Röhm & Haas AG brought polymethyl methacrylate (PMMA) to the market under the trade names Perspex and Plexiglass, respectively. Other names that this material is known by include, but are not limited to, acrylic glass, Acrylite, and Lucite.

Properties

Acrylic is a synthetic polymer belonging to the class of thermoplastics. It is a clear material that resembles glass in many characteristics but offers certain advantages, including greater transparency and being lightweight. Its production relies on polymerization (emulsion, solution, or bulk) of the methyl methacrylate monomer. Like many polymers, it is a petroleum-based polymer as it relies on the petrochemical industry for the production of the required starting monomer, MMA. However, effort since then has gone into developing more environmentally friendly production processes, such as bio-based or carbon dioxide-based MMA production routes, catalytic processes that minimize waste and energy consumption, and novel recycling methods.

Acrylic can be produced and processed in order to fine-tune some of the characteristics of the material. It can be cast, which is suitable for high-end optical and architectural applications, or extruded, making it suitable for applications such as displays and light diffusers. Cell casting is a particularly attractive production process as it yields the highest quality PMMA sheets. It is noteworthy to highlight that PMMA is rarely distributed as an end product. Fillers, comonomers, and additives are often used in various formulations of PMMA such that the characteristics of the end material are optimized for its application.

• Acrylic is a synthetic polymer developed in the 1930s, known as polymethyl methacrylate (PMMA), or under trade names such as Plexiglass, Perspex, Acrylite, and Lucite; the monomer required for its production is methyl methacrylate (MMA).
• The production process (cast or extrusion), as well as additives, comonomers, and fillers, can be used to fine-tune the characteristics of the material.

Tensile Strength

Acrylic is considered to be a strong and tough material that demonstrates good impact strength, even better than glass or polystyrene. With a density of up to 1.20 g/cm³, it is also up to 50% lighter in weight than glass. Butyl acrylate can be added to the formulation of PMMA to further increase the material’s impact strength. As an organic glass, acrylic is highly durable, making it suitable for outdoor applications. It exhibits low flexibility and can withstand moderate loads without deformation occurring. For most applications, shattering is not a concern, as acrylic tends to break into large, dull pieces. However, it has moderate resistance to friction, with abrasive materials, in particular, being able to cause surface scratches, making the use of scratch-resistant coatings a requirement for certain applications. Moreover, it is easily polishable, allowing for the removal of fine scratches and the restoration of optical clarity.

• Acrylic is a strong, tough, and durable material with good impact strength, being 50% lighter than glass.
• The material exhibits low flexibility and moderate resistance to friction. Despite being scratch-prone, it is polishable.

 Resistance

Acrylic has poor chemical resistance, as most organic solvents will either dissolve it or cause the material to swell. This poor chemical resistance arises from the presence of the labile ester groups (–COO–) that are susceptible to hydrolysis. Nonetheless, while the material is not highly susceptible to water, it is not waterproof either. Although it is not hygroscopic, demonstrating water absorption of up to 0.4% by weight over 24 hours, prolonged exposure may alter the material’s mechanical properties and reduce its strength. 

• Acrylic demonstrates poor chemical resistance to most organic solvents, as it features liable ester groups prone to hydrolysis.
• The material is moisture-resistant, but prolonged exposure to water may reduce strength and alter mechanical properties. 

Acrylic demonstrates good temperature resistance within the range of –40 to 80 °C (–40 to 176 °F), with long exposure times to a temperature higher than 80 °C resulting in potential loss of structural integrity and optical clarity. The use of additives or comonomers can further enhance the thermal resistance of the material. The glass transition temperature is 105 °C (221 °F), meaning that at room temperature, PMMA is considered an organic glass. Above this temperature, the rigid nature of the material changes to a more flexible state. 

• Acrylic has good temperature resistance between –40 and 80 °C (–40 to 176 °F); however, long exposure times to higher temperatures can decrease structural integrity and optical clarity.
• It has a glass transition temperature of 105 °C (221 °F), above which the material changes from a rigid state to a more flexible nature. 

Transparency

One of acrylic’s advantages is its transparency; the material can transmit up to 92% of visible light and reflects roughly 4%, making it a good alternative to glass. Moreover, it filters ultraviolet (UV) light below 300 nm, with certain additives increasing this range up to 400 nm. Overall, acrylic demonstrates inherent UV resistance and can block up to 90% of this type of radiation. While prolonged exposure to strong UV radiation may cause some surface degradation and color change, acrylic outperforms most transparent plastics, such as polycarbonate (PC). In terms of infrared (IR) light, it can block radiation over 25,000 nm while passing that of up to 2,800 nm, making it suitable for heat sensor applications where colored acrylic blocks visible light but allows IR radiation to pass. 

• Exhibiting high transparency of up to 92% and reflectance of roughly 4%, acrylic is a good alternative to glass.
• Its inherent UV resistance can block up to 90% of UV radiation; prolonged exposure may cause color changes and surface degradation.
• Colored acrylic that blocks visible light while allowing IR radiation to pass is used for heat sensor applications.

Transparency

Exhibiting good strength, high transparency, and lightweight properties make acrylic a popular choice for its use in furniture, aquariums, roof panels, and DIY projects. However, its environmental impact must be taken into consideration. As mentioned earlier, this polymer relies on the petrochemical industry for its production. While waste and energy consumption management are crucial to controlling the environmental impact, focusing on recycling rather than solely on greener production methods is worth highlighting. The industry has indeed made strides in developing advanced chemical methods to break down PMMA back into its monomer, which, after some processing, may be used anew, thus minimizing waste. Other efforts of recycling include the repurposing of acrylic glass in jewelry and artisanship. 

• Acrylic remains a popular choice for various applications in construction and DIY projects.
• Recycling is as important as managing production and waste in balancing the benefits of acrylic with environmental responsibility. 

Note:

While Acrylic and polycarbonate (PC) are similar materials and can often be used interchangeably, several factors may influence one’s choice according to the specific needs of the application. Acrylic is more economical and is better suited for applications where tensile and flexural strength, UV resistance, and transparency are prioritized. On the other hand, PC presents an improved impact strength, as well as better chemical and heat resistance.