HDPE/pristine

Figure 3.10 SEM micrographs of HDPE/pristine CB (Al, A2) and HDPE/HDPE-g-CB (Bl, B2) with the CB content at 1.0 and 10.0 wt%, respectively.

Thin films of different HDPE nanocomposites containing 2.5 wt% of MWCNTs, pristine and OMMT, and Si02 nanoparticles were exposed to accelerating weathering. The FTIR spectroscopy confirmed the MWCNTs stabilization effect on... 

The consequence of UV irradiation is the progressive decrease in the polyethylene viscosity [58]. This essential element must be correlated with the modification of diffusion property of polymer, by which the degradation is significantly accelerated. The type of nanofiller (multi-waUed carbon nanotubes, fumed silica, neat Cloisite and modified Cloisite) influences differently the behavior of pristine HDPE [59]. The increase order of tensile strength measured at Yield point places the contribution of studied nanoparticle phases for the first 100 h of UV exposure describes promotion of a crosslinking process involving the radicals formed by photolysis. 

Figure 5.15a, b show FUV spectra in the 120-300 nm region of pristine polymer films of three kinds of PEs (HDPE, LDPE, and LLDPE) and PVC, respectively. We cannot discuss the differences in the band intensities of these spectra below 170 nm because it was difficult to control the film thickness by casting the samples. However, it is clear from Fig. 5.15a that the intensity of the absorption band near 185 nm is quite different among the three kinds of PE films. LDPE, which has the large side chains compared with HDPE and LLDPE, shows a significantly stronger band near 185 nm. Thus, it is likely that the band near 185 nm is due to the branches of the PEs. 

The load of grafted polyethylene can be calculated quantitatively according to the TG measurement. The pristine CB and HDPE-g-CB showed 1.2 and 11.2 wt% total weight loss at 500 °C, respectively. The weight percentage of grafted polyethylene in the HDPE-g-CB after extraction was about 10.1%. 

The HDPE/CB and HDPE/HDPE-g-CB composites were thus prepared by mixing the HDPE pipe materials with pristine CB and... 

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