Composite materials include some of the most advanced engineering materials today. The addition of high strength fibers to a polymer matrix can greatly improve mechanical properties such as ultimate tensile strength, flexural modulus, and temperature resistance. Examples are illustrated in the table below.
Typical Values of Filled and Unfilled Polymers for Injection Molding
| Ultimate Tensile Strength (MPa) | Flexural Modulus (GPa) | Deflection Temperature at 1.8 MPa load (°C) | ||||
| Unfilled | With 30% Glass Fiber | Unfilled | With 30% Glass Fiber | Unfilled | With 30% Glass Fiber | |
| Polyetheretherketone | 90 | 150 | 4 | 10 | 160 | 285 |
| Polyphenylene Sulfide | 70 | 140 | 5 | 11 | 120 | 260 |
| Epoxy | 70 | 150 | 2.5 | 25 | 175 | 200 |
| Phenolic | 60 | 90 | 3 | 20 | 180 | 250 |
| Thermoset Polyester | 60 | 140 | 3 | 8 | 130 | 220 |
| ABS | 40 | 90 | 2.5 | 7 | 90 | 110 |
Additives can also be included in polymers for reasons other than thermo-mechanical property improvements. For example, graphite, PTFE, or molybdenum disulfide are added to polymers as lubricants to lower the coefficient of friction or wear rate in tribological applications such as bearings or slide plates.
MatWeb has entries for well over 8000 polymers, including both thermoplastics and thermosets, which have been reinforced through the addition of glass fiber, carbon fiber, aramid fiber, wood, or mineral reinforcements. Not all of these are cutting edge products; some merely include inexpensive inorganics such as calcium carbonate or talc as a way of achieving improved dimensional stability in commodity grade plastics such as polypropylene.
Since the vast majority of polymer-based composites are generally processed and sold as polymers, MatWeb has categorized them according to the base resin in our material property data search tools. Some manufacturers of composite materials do not even disclose the identity or quantity of reinforcing fibers or the matrix material for competitive reasons.
MatWeb has other structural composite materials, offering higher performance, in addition to filled polymers. For example, you can find 'Metal Matrix Composite' listed in the "Nonferrous Metal' section of our Material Type Search or 'Composite Fibers' and 'Composite Core Material' listed under 'Other Engineering Materials'.
A good strategy to find the composite material of choice for your application from the MatWeb Property Search is to pick a category such as polymers, thermoset, or epoxy and specify a minimum tensile strength or flexural modulus from the property field. Two MatWeb materials categories on our Search and Index page that explicitly target composites are 'Carbon Fiber/Thermoset Composite' and 'Composite SMC' (Sheet Molding Compound). SMCs consist of polymer resin and reinforcing agent (glass or carbon fiber) produced and sold in continuous sheets. SMCs, usually thermoset-based, often have longer fibers and higher fiber content than composites produced for injection molding or extrusion. This can result in a stronger and stiffer product, but the ability to form complex shapes from SMCs is limited is limited.
