Polypropylene and polyester are both popular synthetic fibers, each with unique properties. To tell them apart, consider their characteristics. Polypropylene is highly resistant to chemicals, abrasion, and moisture, making it ideal for outdoor and marine applications. It also has a lower melting point than polyester, which can be relevant in applications involving heat. On the touch, polypropylene tends to feel more waxy or plasticky, whereas polyester feels more fabric-like and is softer. Polyester, on the other hand, is known for its strength, durability, and resistance to shrinking and stretching, making it a favorite for clothing and furnishings. Additionally, polyester dyes better, offering more vibrant colors than the typically more muted tones of polypropylene. Burn testing, where a small sample is set alight, can also be informative: polypropylene melts and smells like candle wax, while polyester burns with a stronger, sweet chemical smell and also drips. However, conducting burn tests should be done with caution and an understanding of the safety implications.

Titanium dioxide TiO2 is typically deemed as safe for the environment. even at low concentrations. This versatile mineral is utilized in numerous everyday items such as sunscreens. paints. and food. However. substantial amounts of its release into the environment could pose a threat to aquatic life and plant species due to its photocatalytic capabilities that generate reactive oxygen species. Several studies have also indicated potential impacts on soil microbiology. Thus. while it is not classified as a major hazard. it is advisable to implement proper control measures to minimize any potential releases into the environment.

The flammability rating of titanium dioxide is 0.