Nelcote E-746 Epoxy Prepreg, 3k 5HS Carbon Reinforced is a high strength, prepreg material compatible with all types of resins. It has a tensile strength of 7200 PSI and a flexural modulus at 76% elongation of 3600 psi. The grade has a carbon content of 2.5%, and no formaldehyde as a binder is present. It has a glass transition temperature of 22 °F at 73% humidity.
Nelcote E-746 is ideal for pressure vessels where we need high strength, lightweight, and semi-rigid material. This material has an epoxy resin castable into a fiber-reinforced, biaxial interlaminar fiber mat. We taper and connect the fiber with varying amounts of core reinforcing fibers. As a result, the carbon content in the primers reduces to 2.5%.
The material is of high strength and stiffness. However, it is also lightweight, significantly expanding the membrane area for use in lightweight structures where weight savings are critical.
Carbon Reinforced Nelcote E-746
The material has two phases, the outer microfibers, and the inner matrix. The fibers in this combination provide excellent strength and stiffness largely due to their high volume weight. As a result, Nelcote can be helpful in very lightweight structures.
Nelcote E-746 material is an interlaminar fiber prepreg with a woven structure of biaxially oriented rays of pre-impregnated carbon fiber mats with a maximum of 1% carbon content. Rayming PCB & Assembly strengthen and make the structure semi-rigid by adding a resin-reinforced glass mat binder into the mass. The fibers also have glass fibers and epoxy resin reinforcement.
The material can help in light to medium weight structures because of its high tensile strength, stiffness values, and low weight. We can find two types of applications. The first is a carbon fiber reinforced polymer composite, where the carbon reinforcement is between 0.2% and 3%, and the prepreg content is between 15% and 25%. This material can be helpful for pressure vessels in aircraft, rockets, spacecraft, and oil rigs. The other application is a structural material where we require low weight and minimal strength.
Nelcote E-746 mechanical properties
The material has two phases, the outer microfibers, and the inner matrix. The fibers in this combination provide excellent strength and stiffness largely due to their high volume weight. As a result, Nelcote can be helpful in very lightweight structures.
As with all carbon fiber materials, Nelcote E-746 consists of carbon fibers produced by pyrolyzing organic compounds such as polyacrylonitrile (PAN) or rayon or carbonizing cotton or wool. We refer to these organic compounds as “precursors.” Carbon fibers also come from pitches derived from pine and other sources. We carbonize the precursors to produce “raw” carbon blacks (RCB). These RCBs are then purified by “capping,” which reacts with an acidic solution to create carbonates, waxes, and other materials.
Once the RCB is fully purified, we process it into large quantities of thinly rolled fibers in a process known as spinning. Spinning occurs when we force a polymer solution through a cylinder of fibers at high pressure and temperatures to draw them into fine threads. We then collect the resulting fibers into bales for processing into carbon fibers.
Nelcote E-746 electrical properties
Unlike most carbon fiber prepregs, E-746 is not a two-phase material. Nelcote E-746 fibers are polyimide and phenolic impregnated and interwoven with the epoxy resin used to hold the fibers together in a cohesive matrix. This matrix is then reinforced by impregnating the fiber core with resin. The fibers are highly conductive, so we use them in electrical products. The high electrical conductivity of carbon fiber makes it possible to achieve a high degree of electrical isolation between components in a multi-layered printed circuit. We can cure the epoxy resin by heat or UV light.
Due to the micro-layered construction of E-746, it is essential in 4 layer PCBs and, more recently, in 3 layer PCBs at several companies and universities, including MIT, Intel, the University of Michigan, and Ford Motor Company.
Nelcote E-746 Physical properties
Nelcote E-746 is an interlaminar fiber prepreg with a woven structure of biaxially oriented rays of pre-impregnated carbon fiber mats with a maximum of 1% carbon content. The structure is strengthened and made semi-rigid by adding a resin-reinforced glass mat binder into the mass.
Volatiles: Less than 2% (approximate)
Nelcote E-746 Thermal properties
When we cure Nelcote E-746 as a one-side laminate in an oven, it has a glass transition temperature of approximately 230 °C.
This process involves heating the material above its glass transition temperature. When we apply heat to the material, the resin becomes viscous and flows through the fiber weave to create a uniform cross-linked structure throughout the laminate. This process is called autoclave cure.
In a resin transfer molding (RTM) process, we force the cured prepreg into a mold and then heated. The heat causes the resin to flow through the fiber structure and cure.
Key Features and Benefits:
1. Meets MIL-R-9300B Type II requirements: Carbon Fiber-Reinforced Plastic (CFRP) and Carbon Fiber-Reinforced Polymer (CRFP).
2. Good electrical properties for RF applications: conductivity 25.6×10 S/m, dielectric constant (dielectric strength) 6.5, tensile and compressive strengths > 15 MPa and > 2 GPa respectively, loss tangent < 0.03.
3. Long ambient out-time for maximum process flexibility: stable for at least 60 days at >140 °C.
4. Soft tack and drape properties: perfect for functional and aesthetic laminate adhesion.
5. Meets flammability requirements: UL94 flame retardant, ASTM D-3843 Type I and II.
6. Excellent retention of mechanical properties: 1% carbon content and maximum 25% resin-reinforced glass mat binder.
Application
Nelcote E-746 is up to six times stronger than steel, with a higher strength-to-weight ratio, and could exceed current regulations. The material has also been very lightweight due to the layers of glass fibers in the fiber structure. However, this weight advantage is offset by the material’s high density, making it less suitable for pressurized applications.
Carbon fiber composites have already found their way into the aerospace industry and are helpful in aircraft and rockets. This is due to their lightweight, high stiffness, and low-density properties. These properties make carbon composites ideal for aircraft like the Lockheed Martin F-35 Lightning II, which requires a high strength-to-weight ratio. They are also helpful as payload fairings on rockets because they can be lightweight enough to carry small satellites into orbit.
1. Fairings:
Small satellites such as CubeSat and MicroSat are very small because they do not require a lot of structure. However, they are still large enough to place it into orbit. Carbon fiber composites are a good option for making these lightweight payload fairings because they can make these fairings stiff enough to hold the satellite but make them light enough for the rocket to carry into orbit.
2. Inlet Ducts:
The inlet ducts of aircraft are suitable to speed up the airflow from the engine inlet towards the engine. However, because the airflow has a high velocity, it can create a lot of drag. Carbon fiber composites can be helpful to make these inlet ducts because they are light enough for the aircraft to carry but stiff enough to reduce drag.
3. Nacelles:
The nacelles of aircraft are suitable to house the engines and control systems. However, these components are very heavy so they can create a lot of drag. Carbon fiber composites can be helpful to make these nacelles because they are light enough for the aircraft to carry and stiff enough to reduce the drag created by these components.
4. Radomes:
Radomes are typically helpful to protect electronic components on aircraft. We can use carbon fiber composites for radomes because they are light enough for the aircraft to carry and stiff enough to reduce the drag created by these components.
5. Secondary Aircraft Structures:
The wings and fuselage of an aircraft carry most of the load of the aircraft. Because these components have a high weight, they can create a lot of drag. Carbon fiber composites can be helpful to make these components because they are light enough for the aircraft to carry and stiff enough to reduce the drag created by these components.
Carbon fiber composites are helpful in military vehicles such as tanks and land vehicles to make these vehicles lighter in weight while maintaining their safety.
Conclusion
Nelcote E-746 has a high strength-to-weight ratio and can be helpful for various military and civilian applications. In addition, carbon fiber composites have found their way into the automotive industry and are making their way into many different vehicle parts. These parts include the roof, engine, and transmission of automobiles and safety components such as automotive airbags and crash absorbers.
