What causes white plastic to turn yellow?

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.

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

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It is recommended that gutters are placed under or 'behind' the drip edge of your roof. A drip edge refers to a component that hangs over the roof...

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What are the white worms in my firewood?

The “worms” are the larvae of wood-boring beetles. With few exceptions, they infest trees that are already dead or dying from other causes and are...

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Can I build my own shed?

Yes, with the right plans you can build your dream shed.

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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.

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Crushed stone or gravel foundations work so well because they allow all water to drain away from your shed. Your shed will stay level and dry on a...

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As with traditional homes, barndominiums may last hundreds of years. However, certain parts of the structure may require repair or replacement...

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How do you lubricate UPVC door hinges?

Use a silicone spray in or around the moving parts, using a cloth to catch any excess or splash back. Move the handle and key to work the spray into the mechanism. Spray the hinges, wiping away any excess, and open and close the door to work in the oil.

safestyle-windows.co.uk - How To Oil Your Door's Moving Parts | Safestyle UK

Doors have working parts so it's essential that these parts are well maintained, you can use standard lubrication oil to ease the friction of the moving parts inside your door We recommend that you lubricate all moving parts at least twice a year and oil any stainless steel hinges, be careful not to use excessive lubrication as this could result in damage. Watch our helpful video below for a step by step guide on how you can properly lubricate your door.

Video transcript

To lubricate your door pull up the handle to expose the hooks or cans. Use a silicone spray in or around the moving parts, using a cloth to catch any excess or splash back. Move the handle and key to work the spray into the mechanism. Spray the hinges, wiping away any excess, and open and close the door to work in the oil.