The symbol for low-density polyethylene (LDPE) is typically represented by the recycling code number 4. This symbol, found on product labels, indicates that the item is made from LDPE, a thermoplastic polymer made from the monomer ethylene. LDPE is known for its flexibility, toughness, and relative transparency, making it popular in applications ranging from plastic bags and containers to tubing and laboratory equipment. The recycling symbol, which consists of a triangle of chasing arrows with the number 4 in the center, helps consumers and waste management systems identify LDPE items for proper recycling and disposal practices.

Polypropylene (PP) is a thermoplastic "addition polymer" made from the combination of propylene monomers. Its applications range from plastic packaging, textiles, automotive parts, to reusable containers. The price of polypropylene is subject to fluctuations based on factors such as crude oil prices, demand in consumer goods, and geopolitical events that affect global trade. Supply chain disruptions also have a significant impact. To stay updated on current prices, it's essential to refer to commodities market reports or financial news platforms that track the petrochemical sector. Prices are often quoted per metric ton and can vary by region. For businesses relying on PP, understanding these dynamics can help in forecasting costs and making informed purchasing decisions.

Ladder yarn necklaces are a stylish and easy-to-make accessory that can add both color and texture to any outfit. To create this necklace, you will need a few items: ladder yarn, scissors, and a crochet hook (typically J or 5 mm). Begin by cutting about 22 meters of yarn from the skein for a comfortable length to work with.

Once you have your desired length, tie a knot roughly 100 centimeters from one end. From there, continue with chain stitching until the necklace reaches your preferred length. It's important to note that the ladder line necklace should be long enough to wrap around your neck twice.