Advances in materials science are setting the path for significant progress in industrial technology. The acquisition of suitable materials is an essential step in the development of any new industry, and in order to utilize new materials in high-performance real-world applications, careful preparation and manufacturing are required.

Polymer composites are the result of the combination of two or more phases of organic or inorganic polymers and with different reinforcements ranging in scale from nano to macro. As reinforcements have unique properties different to the components that make up the polymer matrix, fibers are the fundamental components of polymer composites that are responsible for bearing the load. The mechanical properties of natural fiber-reinforced polymer (FRP) hybrid composites are quite diverse and include tensile strength, compressive strength, flexural strength, and impact strength. These qualities are elucidated and streamlined as an examination of each of the natural FRP hybrid composites that are available is carried out. According to recent research, the mechanical properties of the vast majority of natural FRP hybrid composites were shown to have considerable improvements when compared to their nonhybrid or single FRP equivalents.

The aim of this Special Issue is to focus on the creation of man-made and naturally occurring composite materials, such as plants and biological substances, through the application of engineering principles. Molecular and material characterization data on the manufacture of the specified polymers, as well as information regarding their applications, are encouraged, as is work investigating in detail the mechanical properties of FRP hybrid composites and modeling and simulation work. Polymers for biomedical applications, energy and environmental applications, sustainability, and high-performance applications are some of the subjects that are discussed in this Special Issue. We welcome both original research and review articles.

Potential topics include but are not limited to the following:

• Fiber-reinforced and particulate-filled plastics
• Synthetic material-reinforced plastics
• Engineered plastics, both reinforced and not
• New plastics, resins, and additives for films
• Multifunctional and multiscale composites
• Microstructural characterization of composites and their constituent phases
• New approaches to the prediction and measurement of mechanical, physical, and chemical behavior, wear behavior, and performance of composites
• Nanocomposites
• Biopolymers and their applications
• Polymers or polyblends intended for engineering use, including structural, load bearing, and electronic and electrical applications
• Biomaterials with a load bearing capacity, including polymer-based dental materials