What is a primary benefit of incorporating mat into the layers of composite structures?

Incorporating mat into the layers of composite structures significantly enhances the bonding between those layers. This is primarily due to the unique structure of the mat, which consists of randomly oriented fibers. When the resin is applied, the fibers not only provide reinforcement but also create a larger surface area for adhesion between the layers. This mechanical interlocking and increased surface area contribute to improved bonding, leading to a stronger and more durable composite structure.

While the other options might seem relevant in some contexts, they do not directly relate to the primary function of mat in composites. For instance, thermal insulation can be influenced by different materials and configurations but is not a major purpose of including mat itself. Similarly, while reducing overall weight is an important general goal in composites, the specific role of mat focuses more on strength and bonding rather than weight reduction. Finally, increasing electrical conductivity is not typically a feature associated with mats in composite applications, as they are often designed to be non-conductive to maintain insulation properties.