The elongation at break of polypropylene (PP) is a measure of its ductility, indicating how much the material can stretch before breaking. Typically, this property of PP varies depending on its formulation and processing methods, but it generally ranges between 100% and 600%. This substantial range is due to factors like the molecular weight of the polymer, the presence of additives, and the processing conditions under which the PP was produced. Higher molecular weights and the inclusion of certain plasticizers can enhance PP's flexibility and thus its elongation at break. This characteristic is crucial in applications requiring material deformation under stress without failure, such as in automotive parts, packaging materials, and textiles. Understanding and controlling the elongation at break is vital for engineers and manufacturers to ensure that PP products meet the requisite standards for specific applications, balancing between strength and flexibility.

Titanium dioxide (TiO2) is a naturally occurring mineral primarily used as a pigment due to its brightness and high refractive index, which gives a vividness to colors. It's found in a vast range of products, including paints, plastics, papers, inks, foods (as a colorant), and sunscreens (providing UV protection). In foods, it's labeled as E171. Furthermore, its non-toxicity and ability to resist discoloration under ultraviolet light makes it particularly valuable in various applications. However, its use, especially in nanoparticle form, has raised health concerns, prompting research into its safety. Regulatory bodies, including the FDA and the European Food Safety Authority, continue to monitor its safety for human use.

Titanium dioxide is a naturally occurring mineral used in a variety of products. It is often found in paints and sunscreens because of its ability to reflect UV light. It's also in food, cosmetics, and medications as a colourant due to its bright white colour. Moreover, it's utilized in the manufacturing of some kinds of paper and plastic and in remediation of wastewater. The commercial use of titanium dioxide has raised health and safety concerns, but most studies identify only minimal risk when used properly.

A resin glass watch refers to a timepiece whose crystal (the transparent cover over the watch face) is made from a type of hardened plastic material, commonly known as acrylic resin or just resin. These types of crystals are lightweight, affordable, and offer a fair degree of impact resistance, making them suitable for casual, sporty, or children's watches. However, they are more prone to scratches compared to their sapphire or mineral glass counterparts. Resin glass is often chosen for watches intended for rugged or daily use where the risk of scratching is mitigated by the ease and low cost of replacement. Additionally, its flexibility and resilience make it less likely to shatter upon impact, providing a durable option for active users. Despite its scratch susceptibility, resin glass remains popular for its practical benefits, especially in watches designed for outdoor or physical activities.