Why does white plastic turn yellow with age?

The team concluded that chiral chemical structures on the surfaces of the polyethylene films are formed during exposure to UV light and are a potential cause for the yellow color of old plastics.

acs.org - Shining light on why plastics turn yellow - American Chemical Society

What is the most effective way to learn piano?

Piano Tips for Beginners Learn the Basics. It may seem obvious but start with the basics. ... Set a Practice Schedule and Stick With It. Practice...

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What is the thickest wood Cricut can cut?

3/32in Cricut Maker Knife Blade: Cuts materials like wood, leather, chipboard, and more up to 3/32in thick with ease and precision. May 11, 2021

Last updated Sep 2, 2019

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“Could Superficial Chiral Nanostructures Be the Reason Polyethylene Yellows as It Ages?”

ACS Applied Polymer Materials

If you own a retro gaming console or have an old roll of packing tape, you’ve seen how plastics turn yellow as they age. Though the cause of this color change has long been attributed to the formation of molecules that act as dyes — the actual chemical changes that take place remained unexplained. Now, researchers reporting in ACS Applied Polymer Materials have identified surface-based chiral nanostructures as the potential culprit. Understanding how and why polymers degrade with age is key to designing alternatives that can avoid these pathways, allowing plastic products to have a longer lifespan. For one of the most commonly used plastics, polyethylene, it’s long been suggested that ultraviolet (UV) light — the same light that gives us sunburns — initiates reactions in the backbone of the polymer’s structure that cause the yellow color change. However, though chemical changes to polyethylene’s polymeric backbone have been observed after exposure to UV light, those new structures cannot account for polyethylene’s yellowing. One emerging way to intentionally modify the color and the ways that plastics interact with light is to create nano-sized “supramolecular” structures on their surfaces that impact plastics’ properties in a controllable way. Inspired by these surface-based technologies, Margaret M. Elmer-Dixon, Melissa A. Maurer-Jones and colleagues wanted to see if such nanostructures formed unintentionally by UV light could be the cause of polyethylene yellowing. The researchers first investigated if potential structures formed on yellowed polyethylene films’ surfaces interacted with circularly polarized light, a type of light whose waves travel with a right- or left-handed rotation. The amount of circularly polarized light absorbed by the film in these experiments changed depending on the film’s orientation, suggesting that the yellowed plastic contains new chemical structures that are chiral, that is, they are directional and aren’t identical to their mirror images. Additional experiments showed that most of the degradation during film yellowing occurred on the surface of the films. The team concluded that chiral chemical structures on the surfaces of the polyethylene films are formed during exposure to UV light and are a potential cause for the yellow color of old plastics. They say that these insights could help researchers design plastic products that last longer before becoming unsightly or unusable. The authors acknowledge funding from the University of Minnesota, Duluth, the University of Minnesota McKnight Foundation, and the U.S. Department of Energy.

What are some bad piano habits?

What are bad habits when playing the piano? Playing too fast. ... Playing too loud or too quiet. ... Incorrect fingering. ... Ignoring or...

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How much is a Steinway grand piano?

between $70,000 and $150,000 The short answer: somewhere between $70,000 and $150,000. For many musicians, a Steinway grand piano is their dream...

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Is French ivory worth anything?

French Ivory is distinguishable from natural ivory by the parallel, non-intersecting, and regular striations that run along pieces. The value of French Ivory items can vary wildly by the type of item and the market it's being sold in. Many of the smaller vanity items can sell on Ebay for under $10 a piece.

dustyoldthing.com - These Celluloid Collectibles Are More Common Than We Thought!

You may have seen items like these on your grandmother’s or mother’s dressing table when you were young. Many vanity items were made from the material commonly known as French Ivory. Actually a form of early plastic, French Ivory was produced as a less-expensive substitute for natural ivory. The material is made by mixing nitrocellulose in a solvent, then adding a wax or oil. Made from celluloid, the versatile material was used to make buttons, knife handles, compacts, manicure sets, jewelry and many other small decorative items. These items were also called Ivorite, Ivoride, and Pyralin. Items like these were in production roughly from 1880 to 1940, with popularity waning as newer and more durable plastics were formulated. Celluloid is well known to be very sensitive to heat and solvents. Natural ivory is known for the striations that run through each piece, especially noticeable once it is carved. These striations can be uneven or inconsistent and create a cross hatch pattern. French Ivory was intended to mimic this natural structure. French Ivory is distinguishable from natural ivory by the parallel, non-intersecting, and regular striations that run along pieces. The value of French Ivory items can vary wildly by the type of item and the market it’s being sold in. Many of the smaller vanity items can sell on Ebay for under $10 a piece. However, a recent Ebay auction garnered over $400 for a lot of five Celluloid bracelets! Despite the fact that many of these items are handed down to younger generations in relatively good condition, the items are still considered desired collectibles.

Do you remember any of these items from your childhood?

Do you have any celluloid French Ivory pieces in your collection now?

What is the point of 0 frets?

A zero fret is a fret placed at the headstock end of the neck of a banjo, guitar, mandolin, or bass guitar. It serves one of the functions of a...

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Are most chefs overweight?

And that stereotype is often accurate — by some estimates, 70 percent of chefs in the U.S. are overweight. Weight gain seems to be par for the...

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How do you fix a key that won't turn?

5 Simple Ways To Fix An Ignition Key That Won't Turn Try Turning The Steering Wheel. Wiggle The Key In The Ignition. Try Lubricating The Lock....

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Do old strings go out of tune faster?

The Strings It might sound simple, but old strings can keep you from that perfect tuning. As they wear, they lost their capability to hold tension,...

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