PC plastic is an amorphous thermoplastic with good electrical properties combined with superior impact strength, and moderate chemical resistance. As a naturally transparent amorphous thermoplastic, polycarbonate is valuable for its ability to efficiently transmit light internally.
What is Polycarbonate (PC) Material?
Polycarbonate is a type of plastic that is known for being really strong and tough. It can handle high temperatures and is resistant to being damaged by impacts. People use polycarbonate in special cases like making protective gear, windshields for cars, eyeglasses, and even in greenhouses to cover plants. It's also used in 3D printing, especially when toughness is important.
Polycarbonate (PC) is a versatile group of thermoplastic polymers characterized by carbonate groups in their chemical structures. Engineered polycarbonates are known for their strength and toughness, with some grades exhibiting optical transparency suitable for applications like polycarbonate lenses. These polymers are easily molded, worked, and thermoformed, making them widely utilized in various industries.
Products made from polycarbonate, often containing the precursor monomer bisphenol A (BPA), can be found in eyeglasses, medical devices, protective gear, auto parts, DVDs, lighting fixtures, and Blu-Rays. Its naturally transparent and amorphous nature enables efficient light transmission, rivaling glass, while its exceptional impact resistance surpasses that of many commonly used plastics.
The flexibility of polycarbonate allows for room temperature shaping without cracking, and it can be reformed without applying heat. Its thermoplastic nature enables easy injection molding and recycling, with a melting point of 260-320 °C and a wide temperature range for effective functionality. Compared to its counterparts like ABS and PVC, polycarbonate exhibits nearly twice the impact strength.
Manufactured by polymerizing bisphenol A and phosgene, polycarbonate can be solvent welded, adhesive bonded, or joined using mechanical fasteners such as rivets. With a tensile strength of 8500 psi and a shrink rate between 0.006 and 0.009 in/in, polycarbonate possesses key properties like ductility at room temperature, machinability with traditional tools, and the ability to be bent with localized heating to minimize stress fracturing.
In pellet form, polycarbonate is easily processed through injection molding or extrusion, making it suitable for various manufacturing processes. Its amorphous nature, lacking the ordered structure of crystalline solids, influences a gradual softening over a wide temperature range. As a hygroscopic material, polycarbonate requires moisture removal before forming, typically achieved through oven soaking.
Polycarbonate is compatible with many substances, including mineral acids, alcohol, mild soaps, petroleum oils, silicone oils & greases, and low concentrations of alkalis. However, it should avoid contact with aromatic and halogenated solvents, which can cause surface whitening and crystallization. Special coatings are available for improved chemical resistance in architectural panels and signs. The chemical resistance of polycarbonate depends on factors such as exposure duration, material temperature, chemical variety, concentration, and stress levels. Combining polycarbonate with polyester enhances chemical and heat resistance, while blending it with ABS improves ductility.
How is Polycarbonate Material Made?
The primary polycarbonate material is meticulously manufactured through a reaction between bisphenol A (BPA) and phosgene (COCl). The synthesis initiates with the treatment of bisphenol A using sodium hydroxide, a process that deprotonates the hydroxyl groups of bisphenol A.
The resulting phenoxide undergoes a reaction with phosgene to form a chloroformate. This chloroformate is then subjected to an attack by another phenoxide. Through this intricate process, approximately one billion kilograms of polycarbonate are produced each year. Various other diols have been experimented with in conjunction with bisphenol A, including bis(4-hydroxyphenyl)cyclohexane and dihydroxybenzophenone. The cyclohexane serves as a comonomer, effectively suppressing the crystallization tendency of the BPA-derived product.
Types of PA (Polycarbonate) Plastic
Polycarbonate sheeting, initially developed by GE and Bayer in the mid-20th century, has evolved in today's plastic materials marketplace. Various developers now offer unique polycarbonate formulas and production processes. Here's a brief overview of some contemporary variations and their applications:
Clear GP Sheet: Engineered for glazing and industrial purposes, Clear GP polycarbonate sheet stands out as the top choice for protection against vandalism and intentional breakage. With an impact strength 250 times that of glass and 30 times that of acrylic sheeting, it is an ideal solution for robust protection.
Clear SL Sheet: Combating the detrimental effects of natural light, Clear SL polycarbonate sheet boasts enhanced UV resistance, prolonging its life and maintaining color stability even in harsh environments. Offering consistent UV protection on both sides, it ensures comprehensive defense against UV rays.
Polycarbonate Mirror Sheet: This versatile sheet mimics the mirror effect of glass while providing heat resistance, superior impact strength, and dimensional and UV stability. Widely used in the automotive and security industries, it serves as the foundation for two-way mirrors and traditional mirrors in demanding settings like vehicles, retail displays, and institutional bathrooms.
The flexibility of polycarbonate enables the creation of products in diverse sizes, shapes, colors, and transparencies. All variations guarantee exceptional strength, functionality, and cost-effectiveness.
Uses of PA (Polycarbonate) Plastic
Polycarbonate is a versatile material widely utilized in various consumer and industrial applications due to its glass-like appearance and lightweight properties. To enhance its durability and resistance to UV light, additives are commonly incorporated, even though polycarbonate inherently acts as a UV blocker. This is particularly beneficial in preventing discoloration, such as the fogging observed in some auto headlamps.
Despite its susceptibility to scratches, polycarbonate finds application in products like eyewear, where coatings are essential to fortify surfaces. Its stability at higher temperatures makes it valuable for medical devices requiring steam sterilization, with alternative sterilization methods including ethylene oxide and radiation through limited cycles.
Consumer products like blenders, food processors, drinkware, nursing bottles, water filter housings, and water bottles often employ polycarbonate or polycarbonate resin to mimic the appearance of glass without the fragility and weight. While the bottled water industry has embraced polycarbonate for larger bottles, concerns about BPA (bisphenol A) leaching into foods have led to the development of BPA-free polycarbonates.
Polycarbonate sheets serve diverse purposes, including prototypes to allow interior views instead of sheet metal, 3D printing in filament form, and protection for automated machinery due to its easy shaping, high clarity, and impact resistance. Additionally, it is employed in bus stop shelters.
The material is extensively used in electrical and electronic devices, such as housings, connectors, battery boxes, optical media, and smartphones, owing to its excellent electrical resistance, insulating properties, heat resistance, and flame retardant characteristics. Polycarbonate also functions as a dielectric in high-stability capacitors.
A notable application is in the production of compact discs, DVDs, and Blu-ray discs. Injection-molding polycarbonate into a mold cavity with a metal stamper creates these discs, featuring a mirrored surface on one side and a negative image of the disc data on the other. Additionally, polycarbonate is employed in sheet and film production for advertisement purposes, including signs, displays, and poster protection.
While typically transparent, polycarbonate material is available in various translucent and opaque forms. Stock shapes such as sheets, rods, and bars are commonly found in clear, black, and white variations.
Physical and Mechanical Properties of PC
* The above properties may be subject to change depending upon the material grade availability.