Application Note:

In order to optimize the properties of carbon nanofiber thermoplastic composites (Nylon 6), a method has been used to tailor levels of fiber breakage and fiber dispersion in extrusion compounding. Although the produced composites show an increase in mechanical properties by the introduction of the carbon nanofibers, the differences between the effect of the different compound conditions on the mechanical properties are statistically significant for only one processing condition. This indicates the robustness of the current system, but at the same time could show an overruling effect of the (higher) shear-levels induced by the injection molding process used.

Source Data:

Discussion:

Top left chart: Stiffness of Nylon 6 composites (processed at specific temperatures and different speeds for the single screw extruder) as a function of fiber weight fraction.

Top right chart: Strength of the produced composites as a function of fiber weight fraction.

Bottom graphs: Specific stiffness (left) and specific strength (right) vs. FS and WATS. Note: FS and WATS are processing parameters.

Our Recommendation:

PPI recommends the following products for ...

Bottom graphs: Specific stiffness (left) and specific strength (right) vs. FS and WATS. Note: FS and WATS are processing parameters.

Our Recommendation:

PPI recommends the following products for ...

Source Data:

Discussion:

Although the two grades of CNF used in this study have different diameters, they show no difference in mechanical and thermal reinforcement effects in a PMMA matrix. PMMA can be reinforced by incorporation of CNF via melt mixing. While at 5 wt% CNF loading, the modulus of the composite fiber increased substantially, similar improvements were not observed at 10 wt% loading suggesting that the optimum reinforcement concentration is below 10%. The nanocomposite fibers also exhibit increased compressive strength and reduced thermal shrinkage as compared to the control PMMA.

Table left: Mechanical properties of PMMA/CNF composite fibers. While tensile strength and elongation were slightly reduced by the presence of CNFs in the PMMA matrix, fiber tensile modulus increased by more than 50%, and fiber compressive strength was more than double by the addition of 5 wt% CNF.

Graph top right: Thermal shrinkage in PMMA and PMMA/CNF composite fibers. At a temperature of approximately 110oC, unfilled PMMA is found to shrink by 30%, the PMMA/CNF (95/5) composite fibers exhibits only 5% shrinkage under these same conditions.

Bottom graphs: Dynamic mechanical properties of PMMA and PMMA/CNF composite fibers dynamic storage modulus (left) and tan δ (right). Both fiber grades were found to increase the high temperature modulus of the matrix polymer. The dynamic mechanical data shows that the glass transition temperature of the PMMA/CNF composite fiber is about 5oC higher than that of the control PMMA. The composite fibers also show tan δ peak of higher magnitude than control PMMA.

Our Recommendation:

PPI recommends the following carbon nanofiber products for use in polymethl methacrylate (PMMA) composites:



Ecommerce Shopping Cart Software by Miva Merchant