Longsheng

In modern industry and daily life, plastic materials are widely used because of their lightness, durability and strong plasticity. Among them, polycarbonate (PC) and acrylic acid (PMMA, commonly known as acrylic or plexiglass) are two common high-performance plastics. They are similar in some aspects, but have significant differences in performance and application. This article will introduce the characteristics, advantages and disadvantages of these two materials in detail, as well as applicable scenarios, to help you make a more informed choice based on different needs.

What is Polycarbonate?

Polycarbonate (PC) is a high-performance thermoplastic engineering plastic known for its excellent transparency, high impact resistance, high temperature resistance (usually about 120-130°C) and good dimensional stability. It is made by the polycondensation reaction of bisphenol A and phosgene or carbonic acid diesters, and is widely used in the manufacture of products such as eyeglass lenses, bulletproof glass, electronic equipment casings, automotive parts, medical devices and optical disks. Despite its outstanding performance, the possible residual bisphenol A component has caused health controversy, and some fields have turned to the development of more environmentally friendly alternative materials.

What are the advantages and disadvantages of polycarbonate (PC)?

Polycarbonate is a thermoplastic engineering plastic known for its excellent impact resistance and optical clarity.

Advantages:

1. Extremely high impact resistance: Polycarbonate is 250 times stronger than ordinary glass and 30 times stronger than acrylic, so it is often used in protective equipment such as bulletproof glass, safety glasses and helmets.
2. High temperature resistance: PC can withstand heat temperatures above 120°C and is suitable for high temperature environments.
3. Good optical properties: The light transmittance is close to 90%, and it can be used for optical lenses, LED lampshades, etc.
4. Lightweight and easy to process: It can be molded by injection molding, extrusion, etc., and is suitable for complex structural designs.

Disadvantages:

• Easy to scratch: The surface hardness is low, scratches are easy to occur, and coating protection is usually required.
• Not UV-resistant: It will turn yellow when exposed to sunlight for a long time, and UV stabilizers need to be added.
• Higher price: Compared with ordinary plastics, PC costs more.

What is Acrylic?

Acrylic, chemical name polymethyl methacrylate (PMMA), is a transparent thermoplastic, commonly known as "acrylic" or "plexiglass". Its light transmittance is as high as 92%, which is better than ordinary glass. It is also lightweight, weather-resistant and UV-resistant, but has weak impact resistance. Acrylic is made by the polymerization reaction of methyl methacrylate (MMA) and is widely used in advertising signs, lamps, display cabinets, car taillights, sanitary products and decorative materials. It can be formed by hot bending, cutting, polishing and other methods during processing, but it is easy to be scratched, and slightly toxic gases may be released during the production process, so attention should be paid to ventilation protection.

What are the advantages and disadvantages of Acrylic?

The advantages and disadvantages of acrylic (acrylic/PMMA) are as follows:

Advantages:

1. High transparency: The light transmittance is up to 92%, which is better than ordinary glass and close to optical glass.
2. Lightweight and durable: Half the density of glass, the resistance to shattering is better than glass (but weaker than polycarbonate).
3. Strong weather resistance: anti-ultraviolet rays, anti-aging, not easy to yellowing or embrittlement for long-term outdoor use.
4. Easy to process: It can be flexibly formed by cutting, hot bending, polishing, bonding, etc., and is suitable for complex designs.
5. Lower cost: More affordable than high-performance plastics such as polycarbonate.
6. Chemical stability: resistant to weak acids, alkalis and greases, suitable for daily cleaning environment.

Disadvantages:

1. Poor impact resistance: susceptible to crushing or scratching by sharp objects, less safe than polycarbonate.
2. Poor tolerance to high temperatures: in long periods of use, the temperature usually does not exceed 80-90°C, and it is prone to softening and deformation at high temperatures.
3. Flammability: Harmful gases will be emitted during the combustion process, which needs to be improved by adding flame retardants.
4. Processing Risks: Cutting or thermoforming may release irritating gases (e.g., MMA monomers) and therefore precautions need to be taken.
5. Insufficient surface hardness: susceptible to scratches by hard objects, additional coating protection is required to maintain the appearance.

Is Polycarbonate Truly Unbreakable in Drinking Glasses?

Recently, the popular polycarbonate (PC) water cups on the market often use "not broken" as a selling point, how resistant is this so-called "indestructible" cup? We use measured data and real-world scenarios to uncover the truth for you.

1. Comparison of laboratory limit tests

In a test environment that meets international standards, polycarbonate exhibits impressive impact resistance:

Impact Strength Test (ASTM D256)

• Polycarbonate: 850 joules/m (impact resistance equivalent to bulletproof glass)
• Ordinary acrylic cup: only 24 joules/m

The difference between the two values is 35 times, so that the fall resistance of the polycarbonate cup is close to that of bulletproof materials.

Drop Test (ASTM F1797)

• The polycarbonate cup with a diameter of 9cm fell freely from a height of 1.2 meters to the concrete surface, and several consecutive tests produced only surface scratches
• An acrylic cup of the same size falls from 0.5 meters and has a spiderweb-like crack, and a fall of more than 1 meter is basically completely shattered

2. The technological code of super strong resistance to fall

This special property is due to the unique structure of the material:

Molecular level "rigidity and softness"

• The rigid benzene ring structure forms a strong skeleton
• Flexible carbonate bonds absorb impact energy
• The amorphous structure distributes the pressure by molecular chain sliding

Energy dissolving mechanism

• The impact instantly produces microscopic cracks to buffer energy
• Stress is evenly distributed to avoid local breakage

3. Real-life scenario test

Tested for daily use

• Office desktop (0.7 m height): intact after 10 consecutive falls (80% breakage rate of ordinary glass for the first drop)
• Kitchen worktop (0.9m with water): 5 times down and still able to use normally (ceramic cup 100% broken)

Extreme environment testing

• Quenching and heating from minus 20°C to 100°C: no deformation of the cup
• 500 kg car crushed: only dents and no cracks

4. Precautions for use

Despite the excellent performance, you still need to pay attention to the boundaries of use:

Breaking the tipping point

• Falling from a height of more than 3 meters may cause the mouth of the cup to deform
• Sharp objects, such as hammers, can still penetrate on impact
• Contact with solvents such as acetone may dissolve the surface

Care tips:

• Avoid scratches by hard cleaning tools
• For long-term outdoor use, it is recommended to choose a UV-resistant model
• Deep scratches should be replaced in time
  
  

Actual measurements have proved that although the polycarbonate cup is not absolutely "unbreakable", its impact resistance is indeed far beyond that of ordinary materials. For scenarios such as accidental falls and temperature changes in daily use, it can indeed provide reliable protection, which is the best choice for consumers who pursue durability. However, care should be taken to avoid extreme violence and do routine maintenance to prolong the service life.

 How to Distinguish PC and PMMA with Simple Methods?

PC (polycarbonate) and PMMA (polymethyl methacrylate) are common engineering plastics that can be quickly identified by simple tests such as combustion, buoyancy, appearance, etc., without the need for specialized equipment. Here's a practical guide to low-cost identification:

1. Combustion test method (fast and intuitive)
Steps:

• Take a small sample and fix it on a metal fixture, away from flammable materials;
• Use a lighter to ignite the edge of the sample and observe the flame color and smoke characteristics;
• After the sample is extinguished, residual odors are identified.

Key points of identification:

• PC Material: Yellow flame with a small amount of pale white smoke; When burned, it emits a phenolic odor, similar to burning wood or disinfectants; It is not easy to self-extinguish after leaving the fire, and may continue to burn.
• PMMA Material: Flame is bright blue, smokeless; Releases aromas similar to fruit candy or sweetness; Quickly extinguish after leaving the fire.
• Safety Tips: The test should be conducted in a ventilated environment, and it is recommended to wear protective equipment such as a mask to avoid inhaling smoke.

2. Buoyancy test method (non-destructive testing)

Preparation Materials:

• Saturated saline: dissolve 40g of salt in 100ml of water (density approx. 1.33g/cm³)
• Transparent glass containers

Steps:

• Cut the sample into 1cm³ pieces;
• Let it sit in salt water for 10 seconds to observe the rise and fall.

Result Judgment:

• PC: density 1.20-1.22g/cm³, sink to the bottom after putting in salt water;
• PMMA: density 1.17-1.20g/cm³, suspended in brine or sinking slowly.

3. Comparison of appearance and physical properties

• Light transmittance: PMMA has a light transmittance of over 92%, close to glass; PC transmittance is about 88-90% with a bluish tint on the surface.
• Scratch resistance: Gently scrape the surface with a metal needle, PMMA is easy to leave obvious scratches, and PC is more scratch resistant and has shallow scratches.
• Bending characteristics: PMMA is prone to whitish and fracture when bending; PC is flexible and can rebound after bending significantly.

4. Advanced Identification Methods

• Chemical reagent method: Wipe the surface with acetone, PMMA will quickly become sticky, and there is no obvious change in PC.
• Ultraviolet fluorescence method: Under ultraviolet light irradiation, PMMA exhibits blue-white fluorescence, and PC has no fluorescence reaction.
• Comprehensive suggestion: Combined with the combustion method and the buoyancy method for cross-validation, the accuracy is higher. If you need to accurately judge precision parts, you can further compare indicators such as light transmittance and impact resistance. If you are still unsure, it is recommended to send it to a specialized laboratory for infrared spectroscopy (FTIR) analysis.

 Which Plastic Has Higher Heat Resistance for Dishwasher Use?

The dishwasher is high temperature and humidity, and it is very important to choose the right material for plastic tableware. Based on authoritative test data and industry certifications, the heat resistance of polycarbonate (PC) and acrylic (PMMA) is compared below.

1.High-temperature core data

Test according to ASTM D648 heat deflection temperature:

• Polycarbonate (PC): 1.8MPa load, heat deflection temperature up to 135°C, continuous use temperature from -40°C to 120°C. UL 499 certified to withstand high temperatures of 80°C in the dishwasher.
• Acrylic (PMMA): The heat deflection temperature is only 95°C under the same conditions, and the continuous use temperature is -20°C to 80°C. It is easy to stress whitening at over 60°C, and deformed at more than 80°C.

2.Dishwasher actual performance

Resistance to high temperature steam

• Polycarbonate (PC): 1 hour in 85°C high temperature steam, no deformation, no fogging, surface hardness to maintain HV 110. After 100 dishwasher cleanings, the light transmittance was slightly reduced from 90% to 88%.
• Acrylic (PMMA): 30 minutes in 70°C steam with micro-cracks, warped edges, and a surface hardness reduced from HV 105 to HV 85. After 50 dishwasher sessions, light transmittance dropped dramatically from 92% to 78%.

In summary, polycarbonate is much more resistant to high temperatures than acrylic and is more suitable for dishwashers. When buying plastic tableware, pay attention to the material characteristics and certifications can ensure the safety of use and the life of the product.

3. Additional comparison of chemical resistance

(1) Dishwashing agent corrosion test