Sintering high performance semicrystalline polymeric powders

Abstract

Poly(ether ether ketone) (PEEK) is high performance semicrystalline thermoplastic with a glass transition temperature of 143°C. The melting point (Tm) is quoted as 334°C. Because of its high thermal transitions, PEEK, requires high temperatures for processing, at least 370–400°C. It has been determined that under the recommended processing conditions PEEK can undergo branching and eventually crosslinks. An alternative to melt processing PEEK is to apply the powder metallurgy technique of sintering. This involves cold (room temperature) compaction of the polymeric powder, followed by pressure free sintering of the resultant green body. We have reported a process for preparing submicron PEEK particles, and the focus here is on the free sintering of these particles with emphsis on the effects of particle size, sintering temperature, and compaction pressure. The data is evaluated using the two particle model developed by Frenkel as well as the crack healing theory developed by Wool.

Consolidation by spark plasma sintering (SPS) of polyetheretherketone

“…Few authors have already proposed a solid state sintering processing of PEEK . Brink et al . employed this route to consolidate the polymer in two steps.…”

A novel technique for the development of acetabular cup by cold isostatic compaction and sintering of UHMWPE powder with optimized processing parameters

“…It is interesting to note that the diffusion point (145°C) is well above the onset melting temperature (132°C) as determined by DSC, but still substantially below the peak melting point of 150°C, which is a well‐known characteristics of polymers. [ 24 ]…”

“…Sintering temperature of a polymer must be higher than that of its onset melting point to achieve the desired mechanical properties at par with that of conventionally melt‐processed polymer. [ 14 ] Differential scanning calorimetry (DSC) studies, mentioned as process ① in Figure 1, are performed on nascent polymer powder (~10 mg) using DSC, STA 8000 (PerkinElmer, UK) at a heating rate of 5°C/min under a nitrogen purge in the temperature range between 40°C and 200°C to confirm the melting zone of GUR 1050.…”

“…[ 13 ] Other studies looked into the polymer sintering process as coalescence of two particles and the analytical models for the above process following Frenkel's model were discussed in detail. [ 9, 14, 15 ] Experimental results were found to validate this model up to some extent, particularly for the first stage of diffusion as approximated by the Newtonian flow. [ 16 ] The surface tension is the prime motivating force for sintering of viscoelastic polymer leading to merge two particles to reduce their total free surface.…”

Synthesis and properties of thio‐containing poly(ether ether ketone)s

“…Wang and Roovers synthesized a modified PEEK by introducing aldehyde and carboxylic acid groups into the backbone of PEEK to improve the processability for membrane applications 18. Brink et al prepared poly[(pyridine ether)‐ co ‐(ether ether ketone)] to form a complex with hydrochloric acid in order to suspend the modified PEEK in water 19. However, this synthesis procedure is fairly tedious.…”