As of my last update in 2023, MatWeb, a free online materials information resource, does not directly list manufacturers by the number for specific materials like polypropylene. Instead, MatWeb provides detailed data on materials properties from various manufacturers globally. For polypropylene, numerous companies worldwide produce this versatile polymer, including industry giants like SABIC, LyondellBasell, and ExxonMobil, among others. The exact number can fluctuate due to market entries and exits. To find specific manufacturers and their products on MatWeb, users can search for polypropylene, and the search results will include data sheets from different producers. For comprehensive and up-to-date lists, consulting industry reports or trade associations might be more effective.

Polypropylene (PP) is a lightweight, thermoplastic polymer highly valued for its versatility in applications ranging from plastic packaging to automotive parts. Key physical properties include its resistance to chemicals, water, and electricity, making it an excellent insulator. PP has a melting point around 160°C, which allows for easy thermal processing and recycling. Its density is approximately 0.905 g/cm^3, making it one of the lighter plastics available. Additionally, polypropylene boasts significant toughness and flexibility, even at lower temperatures, which contributes to its durability in various uses. However, it does have limitations in UV resistance and can degrade if not properly treated or stabilized for outdoor use. Enhancements through copolymerization or additives can improve its mechanical properties and expand its application range.

The presence of inherent defects. such as pores or interstitial spaces. within the lattice structure of titanium dioxide TiO2 can greatly affect its heat transfer performance. These imperfections hinder thermal conductivity by scattering phonons. which are the primary heat carriers in insulators. As the amount of thermal energy rises. so does the concentration of these defects. resulting in increased scattering and decreased efficiency in heat transfer. Therefore. comprehending and managing this defect concentration is crucial for tailoring TiO2 to various uses. such as thermoelectric devices and thermal barrier coatings.