What are the Uses of Acrylic?

Due to its transparent properties, lightweight and superior toughness compared to glass, PMMA got popular during World War II. It was extensively used make aircraft windshields, canopies and gun turrets. After this several other commercial applications were developed for PMMA such as glass roofing, façade design, advertising, automotive headlamps, etc.

Today various types of acrylic grades are used in wide variety of applications, for example:

Architecture and Construction
Thanks to its excellent impact and UV resistance, PMM is widely used in window and door profiles, canopies, panels, façade design, etc. It also facilitates light transmission and provides good heat insulation, hence a suitable choice of building green houses. PMMA is also used to build aquariums and marine centers.

Lighting
PMMA sheets are used for designing LED lights where it helps maximize light emitting potential. It is also used for construction of lamps thanks to its transparency and optical properties.

Automotive and Transportation
In vehicles, PMMA sheets are used in car windows, motorcycle windshields, interior and exterior panels, fenders etc. Also colored acrylic sheets are used in car indicator light covers, interior light covers etc. It is also used for windows of a ship (Salt resistance) and aviation purposes.

PMMA also open new design possibilities for car manufacturers thanks to its pleasant acoustic properties, outstanding formability and excellent surface hardness.

Electronics
Due to its excellent optical clarity, high light transmission and scratch resistance, PMMA is widely used in LCD/LED tv screens, laptops, smartphones display as well as electronic equipment displays. PMMA also finds used in solar panels as cover materials thanks to its excellent UV resistance and excellent light transmission allowing high energy conversion efficiencies.

Medical and Healthcare
PMMA is a high purity and easy-to-clean material and hence used to fabricate incubators, drug testing devices, storage cabinets in hospitals and research labs. Also, due to its high bio-compatibility, PMMA is also applied as dental cavity fillings and bone cement.

Furniture
PMMA offers exception properties such as transparency, toughness and aesthetics to produce chairs, tables, kitchen cabinets, bowls, table mats etc. in any shape, color or finishes

PMMA Vs PC

Acrylic, Polycarbonate and glass are all transparent materials and as discussed above, PC and PMMA are suitable, shatter-resistance alternatives to glass. PMMA is often used as a lightweight alternative to glass and a reasonable substitute to polycarbonate (PC) thanks to its cost-effectiveness and when extreme strength is not essential.

Also, PMMA is less likely to scratch and does not yellow over a period of time. The other benefits which PMMA offers PC includes very high transmissivity and better optical clarity which can be also be restored by polishing. PMMA is a great choice for optical devices because it is less damaging to tissues when it is fractured.
Although, by making PMMA/PC blends, the excellent optical clarity and surface hardness of PMMA can be combined with the superior toughness and very high glass transition temperature of PC.

How PMMA is made?

Poly(methyl methacrylate) is produced by free‐radical polymerization of methyl methacrylate in mass (when it is in sheet form) or suspension polymerization

PMMA Processing Conditions

PMMA is suitable for processing by injection molding, extrusion, extrusion blow molding (impact modified acrylics only), thermoforming and casting.

Pre-drying is not necessary if a vented cylinder is used but if a normal cylinder is used then PMMA must be processed dry and it is advisable to pre-dry the granules for up to 8 hours at 70-100°C. Surface defects and blisters will form if damp granules are processed.

Injection Molding

·         Melt temperature : 200-250°C

·         Mold temperature : 40-80°C

·         High injection pressures are needed because of poor flow properties and it may be necessary to inject slowly to get the correct flow

·         Internal stresses can be eliminated by heating at 80°C

Extrusion

·         Extrusion temperature : 180-250°C 

·         A degassing screw with an L/D ratio of 20-30 is recommended

PMMA can be welded by all the plastics welding processes such as hot‐blade, hot‐gas, ultrasonic or spin welding.

Due to its transparency and stiffness, PMMA is also used as 3D Printing material but it requires slightly high temperature and a bit more prone to wrap as compared to PLA. PMMA filaments are available in wide array of colors.

Toxicity and Recyclability of PMMA

Polymethyl methacrylate is highly biocompatible, 100% recyclable and non-biodegradable material. PMMA is considered as a group 7 plastic.

There are several ways to recycle PMMA. Often these recycling processes involve pyrolysis, in which the PMMA is extremely heated in the absence of oxygen. Another procedure involves depolymerization of PMMA using molten lead to obtain the monomer MMA in a purity >98%. However, this recycling process is not environmentally viable due to use of lead and production of harmful byproducts and therefore limiting the use of the acrylic.

Recycled Acrylic can be formed into sheets that are used in construction for windows and doors, medical sector, advertising industry and more.

Acrylic is a “BPA-Free” substitute for PC and non-toxic in solid form.

PMMA is naturally compatible with human tissue, and was a frequent component of contact lenses in the past; it's also been used for dentures and bone replacement.