--- title: Relationship Between Crystallinity & Clarity in Polypropylene Sheet description: Clarified PP resins offer drastically improved clarity, haze and overall aesthetics. So how does this work? Learn more about clear polypropylene sheet! image: https://blog.impactplastics.co/hubfs/UltraClear%20PP%20Images/Impact-Plastics-Food-Packaging-UltraClear-PP-social.jpg --- [![Impact Plastics](https://blog.impactplastics.co/hubfs/raw_assets/public/ImpactPlastics_October2020/images/impact-logo-full.svg "Impact Plastics")](https://impactplastics.co) [![Impact Plastics](https://blog.impactplastics.co/hubfs/raw_assets/public/ImpactPlastics_October2020/images/impact-shape.svg "Impact Plastics")](https://impactplastics.co) - [Markets](https://impactplastics.co/markets/) - [Medical Packaging Kits & Trays](https://impactplastics.co/markets/medical-packagingkits-and_trays/) - [Medical Equipment](https://impactplastics.co/markets/medical-equipment/) - [Medical Device](https://impactplastics.co/markets/medical-device/) - [Pharmaceutical Packaging](https://impactplastics.co/markets/pharmaceutical-packaging/) - [Cosmetic Packaging](https://impactplastics.co/markets/cosmetic-packaging/) - [Point of Purchase Display](https://impactplastics.co/markets/point-of-purchase-display/) - [Consumer Goods Packaging](https://impactplastics.co/markets/consumer-goods-packaging/) - [Building & Construction](https://impactplastics.co/markets/building-construction/) - [Electronics Packaging](https://impactplastics.co/markets/electronics-packaging/) - [Class A Surface Automotive](https://impactplastics.co/markets/class-a-surface-automotive/) - [Industrial Automotive & Transportation](https://impactplastics.co/markets/industrial-automotive-transportation/) - [Food Packaging Containers](https://impactplastics.co/markets/food-packaging-containers/) - [Barrier Medical Packaging](https://impactplastics.co/markets/barrier-medical-packaging/) - [Barrier Food Packaging Containers](https://impactplastics.co/markets/barrier-food-packaging-containers/) - [Printing Rollstock](https://impactplastics.co/markets/printing-rollstock/) - [Materials + Applications](https://impactplastics.co/materials-and-applications/) - [Polypropylene (PP)](https://impactplastics.co/materials-and-applications/polypropylene-pp/) - [Polystyrene (PS)](https://impactplastics.co/materials-and-applications/polystyrene/) - [Polyethylene (PE)](https://impactplastics.co/materials-and-applications/polyethylene/) - [ABS](https://impactplastics.co/materials-and-applications/abs/) - [TPO](https://impactplastics.co/materials-and-applications/tpo/) - [Thermoforming](https://impactplastics.co/materials-and-applications/thermoforming/) - [Printing & Graphic Arts](https://impactplastics.co/materials-and-applications/printing-graphic-arts/) - [Form Fill and Seal](https://impactplastics.co/materials-and-applications/form-fill-and-seal/) - [Capabilities](https://impactplastics.co/capabilities/) - [Custom Development](https://impactplastics.co/capabilities/custom-development/) - [Performance Additives](https://impactplastics.co/capabilities/specialty-additives/) - [Extrusion Capabilities](https://impactplastics.co/capabilities/extrusion-capabilities/) - [About Us](https://impactplastics.co/about-us/) - [Quality Control](https://impactplastics.co/about-us/quality-control/) - [Sustainability](https://impactplastics.co/about-us/sustainability/) - [Leadership](https://impactplastics.co/about-us/leadership/) - [Careers](https://impactplastics.co/about-us/careers/) - [Innovative Insights](https://blog.impactplastics.co/blog/) - [Contact Us](https://impactplastics.co/about-us/contact-us/) [Start Your Project](https://impactplastics.co/about-us/contact-us/) [![Impact Plastics](https://blog.impactplastics.co/hubfs/raw_assets/public/ImpactPlastics_October2020/images/impact-shape.svg "Impact Plastics")](https://impactplastics.co) MENU [Start Your Project](https://impactplastics.co/about-us/contact-us/) [![Impact Plastics](https://blog.impactplastics.co/hubfs/raw_assets/public/ImpactPlastics_October2020/images/impact-logo.svg "Impact Plastics")](https://impactplastics.co) [Start Your Project](https://impactplastics.co/about-us/contact-us/) - [![Impact Plastics](https://blog.impactplastics.co/hubfs/raw_assets/public/ImpactPlastics_October2020/images/impact-logo-footer.svg "Impact Plastics")](https://impactplastics.co) ![Close](https://blog.impactplastics.co/hs-fs/hubfs/raw_assets/public/ImpactPlastics_October2020/images/close-ic.png?width=50&name=close-ic.png "Close") ### June 15th, 2018 # Relationship Between Crystallinity & Clarity in Polypropylene Sheet - - ![UltraClear Polypropylene Tray](https://blog.impactplastics.co/hs-fs/hubfs/UltraClear%20PP%20Images/UltraClear%20Polypropylene%20Tray.png?width=174&name=UltraClear%20Polypropylene%20Tray.png)Polypropylene is a semi-crystalline polymer, and characteristic of these type of polymers, PP appears hazy in its natural state. But there are also clarified PP resins that offer drastically improved clarity, haze and overall aesthetics when compared to “neat” PP. So how does this work? Continue reading to learn more about the relationship between crystallinity and clarity in polypropylene sheet.   As noted above, [PP is a semi-crystalline polymer](https://blog.impactplastics.co/blog/learn-more-about-your-plastic-sheet-7-key-facts-about-polypropylene), which is what contributes to the haze appearance in its natural state. At the molecular level, [semi-crystalline polymers](https://blog.impactplastics.co/blog/the-difference-between-amorphous-semi-crystalline-polymers) exhibit organized and tightly packed molecular chains. The areas of crystallinity are called spherulites and can vary in shape and size with amorphous areas existing between the crystalline areas. The degree of crystallinity affects many characteristics of the polymer such as stiffness, as well as the chemical and thermal resistance of the material. Polypropylene normally crystallizes slowly, forming collections of large and complex crystals or spherulites. The growth of these spherulites is initiated around microscopic “sites” naturally present in the material. This phenomenon is called nucleation. Without the addition of a clarifying additive, the size of the spherulites grow to be larger than the wavelength of visible light, resulting in light scattering and hazing the material. ![Natural PP vs UltraClear PP](https://blog.impactplastics.co/hs-fs/hubfs/UltraClear%20PP%20Images/Natural%20PP%20vs%20UltraClear%20PP.png?width=300&name=Natural%20PP%20vs%20UltraClear%20PP.png)The addition of the clarifying agent increases the rate of crystallization throughout the polymer. Because there are more crystals packed into the same space, the crystals grow smaller, allowing for light transmission and enhanced clarity. So now you can take advantage of all of the [wonderful characteristics inherent to PP](https://blog.impactplastics.co/blog/10-reasons-to-use-polypropylene-for-your-next-food-packaging-project) while still achieving a part with the visual appeal desired by todays consumers.  To learn more visit [Milliken Chemical.](http://millikenchemical.com/nx-ultraclear-pp/) --- To learn more about [UltraClear Polypropylene](https://blog.impactplastics.co/blog/5-benefits-youll-see-tomorrow-by-using-ultraclear-polypropylene-sheet) and [clarified impact copolymer polypropylene sheet options](https://blog.impactplastics.co/blog/new-product-announcement-903d-clarified-impact-copolymer-polypropylene-sheet) from Impact Plastics, check out our website or [contact our team today](https://impactplastics.co/about-us/contact-us/)! - [![Impact](https://blog.impactplastics.co/hubfs/raw_assets/public/ImpactPlastics_October2020/images/impact-logo.svg "Impact")](https://impactplastics.co/) © Impact Consumer Products Group – All Rights Reserved 2026 - [Privacy Policy](https://impactplastics.co/privacy-policy/) 5 Highland Drive Putnam, CT 06260 Phone: 860-963-1976 General Fax: 860-963-1998 ###### Stay Connected - [Twitter](https://twitter.com/Impact_Plastics) - [LinkedIn](https://www.linkedin.com/company/impact-plastics-ct/)