POLYCARBONATE (PC)

Polycarbonate is one of the most popular engineering plastics due to its properties of being as transparent as glass and nearly indestructible when it comes to impact strength. It is designed to help engineers and designers, and procurement teams, understand and select the appropriate polycarbonate material and grade with confidence. This guide from Shober Shimi website provides a clear and practical overview of what polycarbonate is, how it’s manufactured, its essential properties and where it’s used.

Polycarbonate is a formless engineering thermoplastic, which is naturally transparent and very tough. It can absorb heavy impacts without cracking or shattering. So, it is an ideal material for use in many projects where glass or more brittle plastics can not be used.

Overview of PC

Polycarbonate plastic is actually a transparent, amorphous thermoplastic that has polymer chains which do not form crystals. This allows PC plastic to be used as a safety plastic, as it can withstand large deformations without fracturing, which is why it is widely used as a structural plastic. The melting and remoulding ability of PC polymer makes it suitable for injection molding and extrusion into polycarbonate sheet as well as for the manufacture of long-life ordinary parts.

The History and Evolution of Polycarbonate Material

Polycarbonate has a history dating back to the 1970s. Bayer (Makrolon) in Germany and GE (Lexan) in the USA have commercialized polycarbonate material in the 1950s. It was soon adopted to meet the demands of automotive, construction and electronics industries for lightweight, impact-resistant glazing and housings. Since then a variety of polycarbonate types have been created, from general purpose grades to optical, flame resistant and medical.

Polycarbonate is a polymer with carbonate groups in its backbone. The most widely used type is bisphenol A (BPA)-based polycarbonate, with a repeating unit of (C16H14O3)n(C_{16}H_O_3)_n(C16​H14​O3​)n​. Its rigid aromatic structure and carbonate groups provide high strength, toughness, and heat resistance.

What is Bisphenol A (BPA)?

Bisphenol A (BPA) is used to make most PC polymer, along with either phosgene or diphenyl carbonate. BPA offers strong rigid aromatic molecules for the construction of strong impact resistant molecular network. The micro-architecture of polycarbonate plastic makes it able to resist cracking and absorb energy, making it reliable in safety glazing, protective casing and critical structural components.

Amorphous Structure and Clarity

Polycarbonate’s morphology is amorphous (non crystalline), where the chains are not arranged in ordered crystals, but are arranged randomly. As there is no large crystalline region to scatter light, visible light can easily pass through PC material. That’s why clear polycarbonate sheet and PC plastic parts can have light transmission ratings comparable to glass, and be much tougher and lighter.

Amorphous Morphology: Why Polycarbonate Is Clear

Polycarbonate has an amorphous (non‑crystalline) morphology, meaning its chains are randomly arranged instead of forming ordered crystals. Because there are no large crystalline regions to scatter light, visible light passes through PC material easily. This is why clear polycarbonate sheet and PC plastic parts can reach light transmission levels similar to glass while staying much tougher and lighter.

The name “almost unbreakable” is often used to describe the impact resistance of polycarbonate, which is particularly renowned. Excellent notched impact strength (many grades even at low temperature).

Mechanical and Physical Properties:

The density of PC is usually at about 1.2 g/cm³, which is not as dense as glass, but still has a firm and sturdy sensation. Balanced low weight and high strength make PC plastic suitable for the automotive industry, transportation and protective equipment.

Optical Properties

Clear polycarbonate plastic offers light transmission typically around 88–90%, close to that of standard glass. Its relatively high refractive index and low haze make optical‑grade polycarbonate a common choice for eyeglass lenses, face shields, protective goggles, and light guides. When surface quality and transparency are critical, manufacturers choose specific polycarbonate types designed for optical applications.

Thermal Stability and Flammability

Polycarbonate has a high glass transition temperature (Tg) of about 147°C, so it keeps its shape and mechanical properties at temperatures that would soften many other plastics. This makes PC material suitable for parts near heat sources or in warm environments. Many polycarbonate types also show good flame resistance, and with proper formulation they can reach UL 94 V‑2 or V‑0 ratings, which is important for electrical housings, electronic components, and appliance parts.

Polycarbonate raw material is made in chemical plants and supplied as pellets or granules for processors. There are two main production routes: interfacial polymerization and melt transesterification.

Synthesis routes

In the traditional interfacial method, BPA reacts with phosgene at the interface between water and an organic solvent, producing high‑molecular‑weight PC polymer. Newer melt transesterification processes react BPA with diphenyl carbonate in the melt, avoiding phosgene and simplifying waste handling. Both routes produce polycarbonate resin that can then be compounded into different polycarbonate types for specific applications.

Processing Polycarbonate: Injection Molding and Extrusion

Processors receive polycarbonate pellets or polycarbonate granules, which must be carefully dried before molding or extrusion to prevent hydrolysis. PC plastic is then melted and injection molded into housings, connectors, and precision components, or extruded into polycarbonate sheet and profiles. Extruded polycarbonate panel and sheet can be further CNC‑machined, routed, drilled, cold‑bent, or thermoformed into final parts such as machine guards, skylights, and protective screens.

There are many polycarbonate types designed for different industries and performance needs. Choosing the right polycarbonate resin or sheet grade is essential for safety, durability, and regulatory compliance.

General‑purpose and optical grades

General‑purpose PC resin is the standard choice for everyday injection‑molded products, enclosures, and clear components. It balances flow, toughness, and cost. Optical‑grade polycarbonate is filtered and controlled more tightly to remove impurities and reduce haze.

UV‑stabilized sheet

Standard PC material can yellow and become brittle when exposed to sunlight for many years. UV‑stabilized polycarbonate sheet solves this issue by adding UV absorbers or co‑extruding a UV‑protective layer on the surface. This UV‑resistant polycarbonate panel is widely used in outdoor roofing, skylights, canopies, greenhouses, and safety glazing where long‑term weathering resistance is required.

Medical and biocompatible grades

Medical‑grade polycarbonate types are formulated to meet biocompatibility standards such as ISO 10993 and USP Class VI. They can tolerate common sterilization methods including autoclave, ethylene oxide, and gamma radiation. These grades are used for housings of medical devices, surgical tools, transparent covers, and fluid‑handling components where both clarity and patient safety are critical.

polycarbonate Grades and specifications

Polycarbonate plastic is used in many industries that need a combination of toughness, clarity, and heat resistance such as automotive, construction, medical, and electronics.

Automotive components and headlights

In cars and commercial vehicles, polycarbonate material is used for headlamp lenses, taillights, interior trim, dashboards, and even panoramic roofs. Because PC plastic is much lighter than glass and stronger than many plastics, it helps reduce vehicle weight while still delivering excellent safety and durability.

Construction panels and safety glazing

In building and construction, polycarbonate sheet and multiwall polycarbonate panel products are used for skylights, wall panels, façades, canopies, and greenhouses. Clear and opal PC panels provide good light transmission with far better impact resistance than glass. For safety and security, laminated polycarbonate panels are used in riot shields, bank and counter screens, machine guards, and hurricane shutters.

Medical Grade and Biocompatible PC

In the medical sector, clear polycarbonate plastic is found in incubators, diagnostic devices, filters, and drug‑delivery systems, where visual control and mechanical strength matter. Electronics manufacturers use flame‑retardant PC polymer and PC blends for laptop housings, smartphone components, connectors, and electrical enclosures. The key benefits are dielectric strength, dimensional stability, and the ability to pass flammability tests.

Understanding the advantages and disadvantages of polycarbonate helps you decide if it is the best fit for your project.

Key advantages

The main advantages of polycarbonate material are its unmatched impact resistance, high optical clarity, and excellent heat resistance. PC plastic is lighter than glass but much stronger, making it ideal for safety glazing and protective equipment. It also offers good dimensional stability and can be molded into complex, precise shapes, which is valuable for high‑performance engineering parts.

Main disadvantages

The biggest disadvantages of polycarbonate plastic are its low scratch resistance and its sensitivity to certain chemicals. Without a hard coating, clear PC sheet can scratch more easily than glass or acrylic. Polycarbonate can also develop stress cracks when exposed to some organic solvents or aggressive cleaners, especially under load. In terms of recycling, PC polymer is usually classified as Resin Identification Code #7, and while it can be recycled, the streams are more complex than standard packaging plastics, so you may need specialized recycling partners.

When choosing a transparent material, designers often compare polycarbonate to acrylic (PMMA) and PETG.

In short, acrylic is clearer and more scratch‑resistant but harder than PC plastic. PETG is easier to process and is naturally BPA‑free, but it cannot match the extreme impact strength and high‑temperature performance of PC polymer.

Polycarbonate remains a leading choice when you need a clear, tough, heat‑resistant engineering plastic. You can buy polycarbonate resin as pellets or granules for molding, or as finished polycarbonate sheet and panel products for construction and safety glazing from Shobeir Shimi. We, as polycarbonate granule supplier, recomand consistent quality and stable processing of polycarbonate type for your application and support you with data sheets and technical advice. Contact us now to get a free quote.

1. How strong is polycarbonate compared to glass?

Polycarbonate is many times stronger than glass in impact and is highly resistant to cracking and shattering, even at lower thicknesses.

2. Is polycarbonate UV resistant?

Base PC material is not very UV resistant and can yellow outdoors, but UV‑stabilized polycarbonate sheet and panels have protective layers or additives that make them suitable for long‑term outdoor use.

3. Is polycarbonate safe for food contact?

Standard BPA‑based polycarbonate resin has been approved for certain food‑contact uses by regulators in various regions, but consumer concern about BPA has led many brands to shift to BPA‑free alternatives and clearly labeled BPA‑free polycarbonate types.

4. How to cut and drill polycarbonate sheet?

You can cut polycarbonate sheet with fine‑tooth saws and drill it with standard metal or wood drill bits, using moderate speeds and good support to avoid vibration and heat.

5. Can polycarbonate be recycled?

Yes, polycarbonate can be recycled, especially clean industrial scrap, but it usually falls into more specialized recycling streams than common packaging plastics.