Two clear plastic samples sit on a designer’s desk. Both look like glass. Both cost roughly the same per kilogram at first glance. One survives a hammer blow and the other splits into sharp fragments.
That gap is the whole story of transparent polymers. “Clear plastic” isn’t one material. It’s a family of resins that trade clarity against impact, heat, and weather resistance, and the trade-offs don’t show up on a sample card.
This transparent polymers comparison breaks down the five workhorse clear resins, polycarbonate (PC), acrylic (PMMA), PETG, PET, and polystyrene (PS), using real property data. You’ll see which material wins each category, which grade to specify, and which optical numbers belong on your purchase order. As a supplier of PC, PMMA, and general-purpose pellets, we want you to choose by the datasheet, not by appearance.
Transparent Polymers Comparison: The Quick Verdict
There’s no single best transparent plastic. You match the material to the property your part can’t compromise on. Clarity, impact, heat, and cost pull in different directions, so the honest answer depends on the job.
Here’s the short version:
- PMMA (acrylic) when you need the clearest, most scratch-resistant, most UV-stable finished part, such as signage, displays, and light covers.
- PC when the part must survive impact and heat, such as safety guards, machine windows, and lighting lenses.
- PETG when you want toughness plus formability and food contact, a genuine middle ground.
- PET when you are making packaging and bottles that gain strength from stretching.
- PS when you need the lowest cost and can accept brittleness, as in disposable packaging and basic labware.
In 40 words: choose PMMA for clarity and weatherability, PC for impact and heat, PETG for a tough and formable balance, PET for packaging, and PS for economy.
Want to see the full head-to-head numbers behind a specific pair? Our polycarbonate vs acrylic pellet comparison does that deep dive, and you can browse our polycarbonate pellet grades while you compare.
What Makes a Polymer “Transparent”?
A polymer counts as transparent when it transmits at least 80% of visible light. Translucent materials fall between 50% and 80%, scattering enough light to appear cloudy. Opacity sits below that range.
Any transparent polymers comparison starts here, because the numbers below decide the whole comparison. Four measurements define how “clear” a material really is, and each matters for a different application:
- Light transmission (TLT): the percentage of visible light that passes through. Higher is brighter and truer.
- Haze: the percentage of light scattered rather than transmitted straight through. Lower haze means a sharper image behind the part.
- Yellowness index (YI): how far the material drifts toward yellow, which matters most for white or color-matched parts.
- Refractive index: how much the material bends light, which governs lens and light-guide design.
Most clear thermoplastics are amorphous, meaning their molecules are arranged without the crystalline regions that scatter light. That’s why PC, PMMA, PS, and PETG can all hold over 88% transmission in a well-processed 3mm section.
Transparent Polymers Comparison: The Master Property Table
The table below pulls typical values for the five main clear resins. Values vary by grade and test method, so always confirm against the supplier’s datasheet.
| Property | PC | PMMA | PETG | PET | PS |
|---|---|---|---|---|---|
| Light transmission (TLT) | 87–91% | up to 92% | 88–89% | 88–90% | 88–89% |
| Haze | Slightly higher, faint tint | Lowest | Low | Low | Low |
| Density (g/cm³) | 1.20 | 1.19 | 1.27 | 1.34 | 1.05 |
| Tensile strength | 60–70 MPa | 70–80 MPa | ~50 MPa | ~70 MPa | 40–59 MPa |
| Tensile modulus | ~2.3 GPa | ~3.2 GPa | ~2.2 GPa | ~2.4 GPa | ~3.25 GPa |
| Elongation at break | ~72% | ~5% | >200% | No break | ~3% |
| Notched impact (Charpy) | ~55 kJ/m² | Brittle | ~10 kJ/m² | High | ~1.5 kJ/m² |
| Max service temperature | 120–140°C | ~80°C | 65–70°C | ~60°C | ~80°C |
| Refractive index | 1.586 | 1.489 | 1.57 | 1.576 | 1.591 |
| UV stability | Needs stabilized grade | Excellent | Moderate | Good | Poor |
| Relative cost | Highest | Medium | Medium | Low–medium | Lowest |
The ERIKS transparent plastics comparison is a useful cross-check on these figures, and SpecialChem’s guide to polymer transparency covers the wider material family. To learn more about PMMA Acrylic Pellets, please refer to our accompanying guide：PMMA Acrylic Pellets: Properties, Grades & Sourcing Guide
Clarity and Light Transmission
In a transparent polymers comparison, clarity is where PMMA leads. It hits up to 92%, which is why high-end displays and optical parts use it. PETG, PET, and PS cluster near 88–89%. PC comes in around 87–91%, with slightly higher haze and a faint tint that most buyers never notice, but that matters for color-matched cosmetics.
Impact Resistance
This is PC’s runaway category in every transparent polymers comparison. A notched Charpy value near 55 kJ/m² is roughly five times PETG and over thirty times PS. PC absorbs energy by deforming, so it dents and bends instead of shattering, which is why safety glazing and protective guards are PC jobs. For the full breakdown against PMMA, see our guide to which material is stronger, polycarbonate or acrylic.
Heat Resistance
PC again leads, holding service strength to 120–140°C. PMMA and PS top out near 80°C, and PETG is the lowest of the group at 65–70°C. That single number disqualifies PETG from most under-hood and heat-exposed applications, even though it’s otherwise tough and easy to form.
Refractive Index
For lenses and light guides, refractive index decides design. PS and PC are the highest at 1.59 and 1.586, which suits light-pipe and diffusion work. PMMA sits lowest at 1.489, giving it the gentlest light bending and the least optical distortion in many lens designs.
Beyond the Big Five: The Wider Clear-Polymer Family
This comparison covers 90% of production decisions, but a few more clear materials matter in specific niches.
- Clear ABS and MABS: tougher than PS, easier to process than PC, and semi-clear rather than glass-clear. Good for housings that need some transparency without full optical quality.
- Optical-grade resins (COC/COP, PEI, PSU): engineered for lenses, light pipes, and medical parts where haze must stay under 1% and heat resistance is critical.
- BPA-free copolyesters (such as Tritan): clear, tough, and free of bisphenol A, which suits drinkware and food-contact parts.
- PVC and cellulose acetate: older clear materials still used in specialty tubing and film.
Specifying Clear Resin: What Belongs on the Purchase Order
Here is where most clarity problems begin. A spec that says “transparent plastic” invites substitution, and in a transparent polymers comparison the difference can take a year to surface.
When Daniel, a plant manager in Guangdong, switched a display-panel supplier to save 8% on resin, he received parts that looked perfect at goods-in. Fourteen months later, customers reported edge clouding and a yellow tint on installed panels. The new resin was an extruded acrylic substituted for the cast grade his spec assumed. The “savings” cost him a full recall and one lost account.
To avoid that outcome, put these items in writing:
- Name the grade and number, such as a specific Makrolon PC or Plexiglas PMMA, and strike the phrase “or equivalent.”
- State optical metrics and methods: TLT, haze, and yellowness index, measured to ASTM D1003.
- Require a certificate of analysis (COA) per batch, not just at first order.
- Specify UV-stabilizer content for any outdoor part, and food-contact or medical certifications where they apply.
- Add a melt flow index (MFI) range so the grade runs correctly on your machine.
Our guide to plastic pellet quality control walks through the full supplier scorecard, and how to verify batch consistency starts with comparing measured values against datasheet limits on every delivery.
Processing for Clarity: Where Haze Comes From
A transparent polymers comparison points you to the right resin, but processing decides whether the part stays clear. You can specify the perfect material and still ship hazy parts, because clarity is fragile and processing loses it in predictable ways.
- Moisture: PC and PETG absorb water from the air. Undried pellets release steam in the barrel, which shows up as splay, silver streaks, and permanent haze. Dry PC to below 0.02% moisture before molding.
- Mold surface and wall thickness: a mirror-polished cavity produces clear parts. Wall sections that are too thick or too thin cool unevenly and trap internal stress that scatters light.
- Contamination: clarity is the first property lost when a clear run follows a colored or filled material. Purge and changeover discipline protects the batch.
- Internal stress: rapid cooling locks stress into the part, which appears as haze or birefringence. Annealing relieves it when clarity is critical.
Because clarity is easy to lose and expensive to recover, the cost of a clear part depends far more on rejection rate than on resin price per kilo. That’s why we track processing and material together, not separately.
UV Stability, Yellowing, and Outdoor Performance
Outdoor use divides the field sharply, and it is the point where a transparent polymers comparison turns decisive. PMMA is naturally UV-stable, so it holds clarity and color for years without help. Standard PC yellows under UV, so outdoor PC parts need a UV-stabilized grade or a hard coat. PETG and PS aren’t suitable for long-term outdoor exposure.
The measurable warning sign is the yellowness index. A part that starts near zero and climbs signals a UV problem before the customer sees it as a color shift. If your application lives outdoors, read our full analysis of transparent material UV resistance before choosing.
Transparent Polymer Costs in 2026
Cost ranks the group clearly for a given part: PS is cheapest, PET and PETG sit low to mid, PMMA is mid-to-high, and PC carries the premium. But the per-kilogram price tells only part of the story.
The real number is cost per acceptable part. Add the rejection rate from haze, the rework from stress cracking, and the warranty claims from yellowing, and the ranking can shift. A cheaper resin that yields 85% usable parts often costs more than a premium resin that yields 98%. We covered the full pricing method in our 2026 cost comparison of polycarbonate and acrylic, and the same logic applies across every transparent polymers comparison.
For most buyers, the winning move is to price the finished, saleable part rather than the pellet, then let the material follow the yield.
FAQ: Transparent Polymers Comparison
Which transparent plastic is the clearest?
PMMA (acrylic) is the clearest at up to 92% light transmission with the lowest haze. In any transparent polymers comparison, PS and PETG come close on transmission but trail on impact and UV stability.
Which transparent plastic is the strongest?
Polycarbonate is by far the strongest under impact, absorbing roughly five times the energy of PETG and over thirty times that of PS. PMMA is stronger in tension and stiffness but brittle.
Is PETG stronger than acrylic?
Yes, for impact. PETG is far tougher than acrylic and can absorb shock without cracking. Acrylic is stiffer and clearer but shatters under a sharp blow.
What is the best clear plastic for outdoor use?
PMMA is the default for outdoor clarity because it is naturally UV-stable. Polycarbonate works outdoors only with a UV-stabilized grade or hard coat. PETG and PS are not recommended for long exposure.
Is polystyrene a clear plastic?
Yes. Crystal PS transmits about 88–89% of visible light and is the lowest-cost clear resin, but it is brittle and has poor UV resistance.
Why is my clear molded part hazy?
The usual causes are undried moisture in PC or PETG, a rough mold surface, wall sections that are too thick, or contamination from a previous colored run.
Conclusion: Choosing Your Transparent Polymer
A transparent polymers comparison comes down to one question: which property can your part least afford to lose? Rank impact, heat, clarity, UV, and cost in order, and the material chooses itself.
- PMMA for clarity, scratch resistance, and outdoor durability
- PC for impact and heat
- PETG for a tough, formable middle ground
- PET for packaging strength
- PS for the lowest cost
Then match the grade to the job and write optical metrics into the spec so no substitution slips through.
Once you’ve run your own transparent polymers comparison, we supply clear PC, PMMA, and general-purpose pellets with batch-level COAs and technical support to help you match grade to application. Request a clear-resin quote and grade recommendation through our contact page, and our team will respond within 24 hours.
