When incorporated into plastic, glass fibers offer several key benefits that enhance the overall properties of the resulting composite material:

1. Increased Strength and Stiffness: Glass fibers are remarkably strong and stiff compared to plastics. When embedded within the plastic matrix, they act like tiny reinforcing rods, significantly improving the composite's tensile strength, compressive strength, and flexural strength. This makes the material more resistant to bending, warping, and breaking under pressure.

2. Improved Dimensional Stability: Glass fibers help the plastic maintain its shape better, especially under varying temperature and load conditions. This is because the fibers resist deformation and expansion, offering dimensional stability that pure plastics often lack.

3. Enhanced Durability: Glass fibers contribute to the overall durability of the composite by increasing its resistance to wear, tear, and impact. This makes the material less susceptible to damage from everyday use, harsh environments, and accidental impacts.

4. Lighter Weight: Compared to using pure metals for similar strength requirements, fiberglass-reinforced plastic (FRP) offers a significant weight advantage. This is particularly beneficial in applications like transportation (cars, airplanes) and construction (building components) where weight reduction translates to improved fuel efficiency and structural integrity.

5. Electrical and Thermal Insulation: Depending on the specific type of glass fiber and the manufacturing process, FRP can offer varying degrees of electrical and thermal insulation. This opens doors for applications in electrical components and heat management solutions.

6. Corrosion Resistance: Glass fibers are generally resistant to corrosion from most chemicals and environmental factors. This enhances the longevity of the composite material, making it suitable for use in harsh environments and applications exposed to chemicals or saltwater.

It's important to note that the specific benefits and their extent depend on the type and amount of glass fiber used, the type of plastic matrix, and the manufacturing process. However, in general, glass fibers significantly enhance the strength, stiffness, durability, and other key properties of plastics, making them valuable in a wide range of applications.