Radiation-induced effects on micro-scratch of ultra high molecular weight polyethylene biocomposites

Effects of reinforcements and gamma‐irradiation on wear performance of ultra‐high molecular weight polyethylene as acetabular cup liner in hip‐joint arthroplasty: A review

“…The transmission electron micrographs of un‐irradiated UHMWPE (Figure 7(c)) revealed the crystal lamellae (white threads, lamellar thickness of 27 ± 3 nm) in a dark background (amorphous). Increase in the stacking of higher lamellar concentration and with increased lamellar thickness (29 ± 3 nm) in comparison with un‐irradiated polyethylene, as shown in Figure 7(d) 193 …”

“…The steps of the oxidation process are as follows (1) the free radicals formation from the cleavage of the C─H and C─C bonds, 194 (2) formation of peroxy free radicals when oxygen react with free radicals 191,192 (3) removal of hydrogen atom by peroxy radicals from other UHMWPE chains to generate hydro peroxides, and (4) formation of oxidation products such as ketones, esters, and carboxylic acid by breakage of unstable hydroperoxides 195,196 . Evidence of the presence of C=O bond after UV and gamma‐irradiation was reported by Nayak et al, 193 as shown in the FTIR plot (Figure 7(b)). The production of oxidation products is accompanied with the chain scission process and, thereby, the decreased molecular weight of UHMWPE further decreases the mechanical strength 197 .…”

“…On the top, the cytocompatibility of gamma‐irradiated UHMWPE‐ based composites should not be compromised. Nayak et al 193 performed MTT assay test by using L 929 mouse fibroblast on both UV and gamma‐irradiated UHMWPE composites which showed more than 80% cell viability after third and fifth days of incubation period, confirmed the cytocompatibility of irradiated samples. The proliferated cells can be well visualized in the SEM micrographs of cultured samples after fifth day of incubation (Figure 8(e,f)) 193 …”

“…(b) FTIR of un‐irradiated, UV‐, gamma‐irradiated UHMWPE. Reprinted with permission 193 (c,d) TEM of un‐irradiated and gamma‐irradiated UHMWPE, respectively.…”

“…(e,f) SEM micrographs of L929 proliferated cells on gamma‐irradiated UHMWPE composites. Reprinted with permission 193 [Color figure can be viewed at wileyonlinelibrary.com]…”