Polypropylene and fiberglass are distinct materials, each with unique properties and applications. Polypropylene is a type of thermoplastic polymer, known for its versatility, chemical resistance, and being used in various industries for products such as containers, textiles, and automotive parts. On the other hand, fiberglass is a fiber-reinforced plastic where glass fibers are the reinforcement. It is famous for its strength, durability, and lightweight properties, making it ideal for construction, automotive, and marine applications. Although both materials are used in composite forms for enhanced characteristics, they are fundamentally different substances and not interchangeable. They can, however, be combined in certain composite materials to exploit both materials' advantages.

Polyester inherently tends to generate and hold onto static electricity, contrary to being anti-static. This propensity is due to its synthetic nature, where the friction between polyester surfaces can lead to a charge accumulation, subsequently causing static cling. However, there are treatments and finishes that can be applied to polyester fabrics to enhance their anti-static properties. These treatments either conduct or dissipate static charge, thereby reducing static cling. Despite these advancements, untreated polyester remains prone to static, especially in dry environments.

To stiffen yarn with cornstarch, you need to create a solution that will harden as it dries. Start by mixing 1/4 cup of cornstarch with about 1/2 cup of cold water. Stir until the cornstarch is completely dissolved. Then, slowly add this mixture to 2 cups of boiling water, stirring constantly until it becomes thick and translucent. Let the mixture cool slightly. Dip your yarn or yarn project into the solution, ensuring it's fully saturated. Gently squeeze out excess mixture without twisting the yarn too much, to maintain its shape. Lay the item on wax paper or a clean surface to dry, shaping it as desired. This method is excellent for projects that need to hold a specific form, like ornaments or sculptures.