Insert‐molded poly(ether imide)/carbon fiber poly(ether ether ketone) bimaterial composites: Fracture and interfacial analysis

Abstract

Bimaterial composites were constructed by injecting carbon-fiber-filled poly(etheretherketone) (CF PEEK) into a mold containing one-half of a poly(etherimide) (PEI) tensile specimen. Specimens were notched at the interface and tested in tension. Using fracture mechanics, the adhesion strength of the interface (a fracture energy with units of energy per area) was calculated from notch size and stressstrain behavior of the notched specimens. Fracture energies (with units of energy per area) of the PEI/CF PEEK bimaterial composites were slightly less than those measured from the monolithic materials of construction. Variations in test speed (below the glass transition temperature of the two components) had little effect on stiffness or fracture energy. However, fracture energies decreased slightly as temperature increased. Composites fractured through the CF PEEK near the PEI/CF PEEK interface. Consequently, the fracture surface of the PEI portion had a thin layer of CF PEEK (a qualitative indicator of good adhesion). Microscopy and X-ray photoelectron spectroscopy confirmed the presence of a thin layer of CF PEEK on the PEI. It appears that the miscibility of PEI and PEEK contributed to the strength of the PEI/CF PEEK thermophysical bond. The strength of the thermophysical bond of the PEI/CF PEEK bimaterial composites was greater than the cohesive strength of amorphous commodity polymers such as polystyrene and should be more than adequate for most microelectronics device handling applications.

Design of Revolute Joints for In-Mold Assembly Using Insert Molding

“…The room temperature to which the polymers cool was assumed to be 28 C. We then calculated the interfacial frictional torque using Eqs. (1) and (2). These results are shown in Fig.…”

“…However, the radial stress has a strong correlation with the thickness ratio k as defined in Eq. (2). A lower value of k results in lower interfacial stress in the joint.…”

“…One of the most noteworthy benefits to using an injection molding based approach to manufacturing robots is its advantage in mass production. To illustrate this, we compared the cost of fabricating the 9 degree of freedom robot structure using the following three strategies (1) Machining and assembly [27], (2) In-mold assembly [10], and (3) In-mold assembly using insert molding (this work). For the purpose of this comparison, we consider the production time as a direct indication of the production cost.…”

“…Popular molding processes for insert molding involve injection molding and resin transfer molding (RTM). Insert molding has become a popular process for several applications such as composite fabrication [2], packaging [3], microfluidics [4], etc.…”

Permeation resistance of poly(ether ether ketone) to hydrogen, nitrogen, and oxygen gases

“…To minimize particle generation, polymers with superior abrasion resistance are often employed at contact points. Poly(ether ether ketone) (PEEK) often is the material of choice for this task 2–4. Once PEEK is incorporated, its mass transport properties will influence barrier performance and outgassing properties of the ME product.…”