Polycarbonate (PC): Properties, Grades and Supply

Polycarbonate as an Industrial Raw Material Category

Polycarbonate (PC) is an amorphous engineering thermoplastic produced by polycondensation of bisphenol A with phosgene or diphenyl carbonate. Unlike most transparent polymers, PC combines high optical clarity with the ability to withstand significant impact loads without failure. This unique property makes it indispensable in the production of protective screens, transparent roofing panels, electronics housings and medical devices. The specificity of the category is determined by the fact that PC is processed mainly by injection moulding and extrusion. Specialised grades are produced for each method, differing in melt flow rate (MFR), presence of UV stabilisers and optical characteristics. Low impact strength in the presence of stress concentrators and susceptibility to stress cracking under certain chemical environments require careful grade selection and adherence to technological regimes.

Chemical Identification and Classification of Grades

Polycarbonate is identified by CAS number 25037-45-0 (bisphenol A polycarbonate). In international trade, HS code 3907.40 is used for polycarbonates in primary forms. Density of the material is 1.20 to 1.22 g/cm3. The glass transition temperature (Tg) is in the range of 143 to 150 degrees Celsius, which determines the upper operating limit without load. In Russian practice, polycarbonate is produced according to TU 2226-173-00203335-2007. Grades are designated by alphanumeric indices, for example PC-003 L (injection) and PC-003R (extrusion). The letter L indicates the injection method, R indicates extrusion. Grades with increased UV resistance, flame retardancy and optical grades are also produced. International nomenclature often uses MFR and purpose designations.

Regulatory Framework and Quality Standards

Circulation of polycarbonate and articles made from it in Russia and the EAEU is regulated by Customs Union technical regulations, in particular TR CU 005/2011 for packaging, TR CU 021/2011 for food contact, TR CU 004/2011 for electrical articles. For finished articles, such as multilayer panels, GOST R 56712-2015 applies. International standards used for identification and control include ISO 1133 for melt flow rate, ISO 1183 for density, ISO 62 for water absorption, ISO 13468-1 for light transmittance, ASTM D256 for Izod impact strength, ASTM D638 for tensile strength, ASTM D790 for flexural modulus.

Physico-Chemical Properties and Optical Characteristics

Key physico-chemical parameters of PC determine its behaviour during processing and operation. Density is 1.20 to 1.22 g/cm3, water absorption over 24 hours does not exceed 0.15 to 0.2 percent. Mechanical properties include tensile strength of 60 to 70 MPa, flexural modulus of 2300 to 2400 MPa, elongation at break of 90 to 110 percent. Izod notched impact strength reaches 12 to 17 kJ/m2 for thin-walled specimens, but decreases significantly at wall thicknesses above 3 mm. Optical properties are the key advantage of PC: light transmittance reaches 89 percent, refractive index is 1.58 to 1.59. The material has high dimensional stability and low shrinkage (0.5 to 0.7 percent). Chemical resistance is limited: PC is resistant to dilute acids, alcohols and fats, but not resistant to alkalis, aromatic and chlorinated hydrocarbons, ketones and esters. Prolonged UV exposure can cause yellowing, so stabilised grades are used for outdoor articles.

Mechanism of Action and Functional Role

In processing, PC acts as a rigid amorphous matrix that transitions to a viscous-flow state on heating and solidifies on cooling, retaining transparency and the formed shape. High impact strength is due to the ability of polymer chains to undergo large reversible deformations, allowing the material to dissipate impact energy without brittle fracture. In compounds, PC acts as a carrier for additives: UV stabilisers protect against photodegradation, flame retardants impart fire resistance, colorants provide colour, glass fibre increases rigidity and heat resistance. Internal lubricants are introduced to improve processability, and special stabilisers to increase hydrolysis resistance.

Applications by Industry

Construction remains the largest consumer of PC. Transparent roofing panels, canopies, awnings, noise barriers and glazing of sports facilities are produced from extrusion PC due to the combination of transparency and impact strength. Electronics and electrical engineering use PC for housings of household appliances, lighting fixtures, connectors and insulators, where dielectric properties and heat resistance are important. Medicine uses special PC grades for syringes, blood containers, surgical instruments and articles subject to sterilisation. Automotive uses PC for headlight lenses, instrument panels and interior parts. Consumer goods include safety glasses, helmets, water bottles and furniture elements. In optics, PC is used for lenses and light guides.

Comparison with Alternative Materials

Compared to polymethyl methacrylate (PMMA, acrylic glass), PC has significantly higher impact strength but inferior weather resistance and a tendency to yellow under UV. PMMA is preferred for outdoor transparent structures with high optical stability requirements, PC for articles where impact resistance is important. Compared to polystyrene (GPPS), PC is significantly stronger and more heat-resistant but more expensive and harder to process. Compared to ABS plastic, PC is more transparent and heat-resistant but less processable and requires higher processing temperatures. Compared to polyamides, PC has better transparency and dimensional stability but inferior chemical resistance to certain media.

Common Processing Challenges

The most frequent problems in PC processing are:

• Insufficient drying. PC is hygroscopic, and moisture causes hydrolysis at high temperatures, leading to reduced molecular weight, bubbles and deterioration of optical properties. Drying at 120 degrees Celsius for 3-4 hours is recommended.
• Melt overheating. Temperatures above 320-340 degrees Celsius lead to thermal degradation, yellowing and reduced impact strength. The recommended processing range is 280-320 degrees Celsius.
• Internal stresses. Rapid cooling and uneven shrinkage cause cracking. Optimising mould temperature (80-100 degrees Celsius) and holding pressure reduces defects.
• Chemical stress cracking. Contact with certain oils, solvents and alkalis causes stress cracking. Careful selection of contact media is required.
• Impact strength loss on repeated processing. Multiple processing cycles lead to polymer degradation and a drop in impact strength, so the number of cycles should be limited.

Quality Control and Laboratory Methods

Quality control of PC includes incoming granule analysis, document verification and laboratory testing. Key parameters: MFR (ISO 1133, ASTM D1238), density (ISO 1183), Izod impact strength (ISO 180, ASTM D256), tensile strength (ISO 527, ASTM D638), flexural modulus (ISO 178, ASTM D790), Vicat softening point (ISO 306), light transmittance (ISO 13468-1), water absorption (ISO 62), residual monomer and volatile content. For food contact and medical devices, sanitary-chemical and toxicological tests are carried out. Laboratory confirmation is especially important for optical grades, since transparency defects and yellowing may only appear after processing.

Storage and Transportation Conditions

PC is stored in dry rooms protected from direct sunlight at temperatures not exceeding 30 degrees Celsius. Granules are moderately hygroscopic, so long-term storage requires protection from moisture. Bags and big bags must be sealed and protected from contamination. Shelf life in original packaging is usually 3 years. Transportation is carried out in 25 kg bags, 500 to 1000 kg big bags and octabins. For export supplies, sea and rail routes are used with protection from moisture and contamination.

Analogue Selection and Interchangeability

PC analogue selection is one of the key services of the portal. We help replace imported grades with comparable alternatives based on MFR, impact strength, optical properties and heat resistance. The algorithm includes analysis of the current grade and its rheological characteristics, determination of permissible deviations in key parameters, selection of options from available sources (Russia, China, other regions), verification of certificates and laboratory data, and organisation of trial batches for testing on the customer equipment. When selecting an analogue, not only MFR and density but also UV stabiliser type, presence of flame retardants, optical characteristics and food-contact compliance are considered. Replacement may require adjustment of temperature profile and drying regime.

Supply Scheme: Worldwide

The portal organises PC supplies worldwide. In Russia, the only polycarbonate producer is Kazanorgsintez (part of SIBUR), which produces PC-003 L and PC-003R grades. However, a significant part of demand is covered by imports from China, South Korea and Europe. Each supply is treated as a separate project with an individual scheme covering grade selection, quality verification, logistics and customs clearance.

Logistics and Customs Clearance

PC logistics includes sea, rail and road routes. For large batches of granules, container and bulk schemes are optimal. Customs clearance is supported by the portal broker: document preparation, HS code 3907.40 classification, certification and interaction with control authorities. The logistics scheme is built for the specific route and customer requirements.

FAQ

How does polycarbonate differ from acrylic glass (PMMA)?

Polycarbonate is significantly stronger and more impact-resistant but less UV-stable and prone to yellowing. PMMA has better weather resistance and optical stability but is more brittle.

Which PC grade is suitable for injection moulding of protective screens?

For injection moulding, grades with MFR of 5-15 g/10 min are typically used, such as PC-003 L. They provide a good balance of impact strength and flowability.

Can polycarbonate be used for food products?

Yes, provided the grade is approved for food contact and has the appropriate sanitary documents. Potential migration of bisphenol A should be considered.

What MFR is needed for sheet extrusion?

For sheet and profile extrusion, grades with MFR of 2-6 g/10 min are used, such as PC-003R. Higher MFR can lead to sagging and web instability.

What documents accompany a supply?

Conformity certificates, quality certificates, sanitary documents for food contact, test reports, origin documents.

Are small batches available for testing?

Yes, trial batches from 25 kg are available for most grades. Terms are agreed individually.

Conclusion

Polycarbonate remains a key engineering thermoplastic for transparent constructions, electronics and medical devices due to its unique combination of transparency and impact strength. A processor success depends on the correct choice of grade considering MFR, optical properties and purpose, confirmed quality and stable supply. The portal helps select analogues, organise logistics and customs clearance, ensuring supply chain transparency worldwide.

Contact Us

If you are looking for PC granules or need advice on grade selection, analogue search and worldwide supply organisation, please contact our team at info@apptrade.ru. We will help you find the right product, verify documentation and organise supply.