Electron and photon emission accompanying deformation and fracture of polycarbonate

Abstract

Electron and photon emission accompanying tensile loading and failure of polycarbonate show weak emissions during the onset of neck formation and intense emissions during the fracture event itself. These results are interpreted in terms of formation of active species by bond breaking followed by emission driven by energy released by recombination. Fast time scale measurements during fracture show that intense electron and photon emission typically begins about 50 μs prior to the completion of fracture and is most intense at the completion of fracture. The gradual onset reflects the final stages of growth of the failure‐initiating defect. Defect growth was monitored by measuring the intensity of a light beam transmitted through the gauge length of the sample; the transmission is sensitive to scattering by surface and bulk defects. A marked decrease in transmission begins some tens of ms prior to fracture due to scattering from the fracture‐initiating defect. These measurements allow accurate correlations of defect growth with the onset of the electron and photon signals. © 1993 John Wiley & Sons, Inc.

Formation of monomer residues in PS, PC, PA-6 and PVC upon γ-irradiation

“…The increase in bisphenol-A level in PC film exposed to 30 kGy could be explained by the predominant cross-linking effect of small doses of g-irradiation (5-10 kGy) and the pronounced scission of main chain at higher doses (30-200 kGy) by the cleavage of the weak carbonyl bond between the phenyl rings. In the present study, the 30 kGy of irradiation is seemed to be sufficient to decompose the vulnerable C-O bonds adjacent to the carbonyl group by unstabilizing the resonance of the phenyl group (Zimmerman et al, 1993;Hirata et al, 2002). The 5 kGy of g-irradiation significantly (po0.05) increased the formation of e-caprolactam in PA-6 from 70.76 to 164.10 ppm.…”

Variation of lexan polycarbonate properties by electron beam

“…The chemical structure of Lexan and the possible chemical reaction after electron irradiation is as shown in Figure 1. This can be explained in the following way: an early investigation by Zimmermann et al8 reports that the CO bonds adjacent to the carbonyl group in the Lexan polycarbonate polymer chain are the vulnerable bonds, lacking the resonance stabilization of the phenyl group. The most important volatile product during Lexan polycarbonate degradation is CO 2 , and hence carbonyl linkage is the most reactive group in the polymer 9.…”

Photon emission during deformation of glass‐fiber‐reinforced bisphenol‐a‐polycarbonate

“…These mechanisms are similar to proposed mechanisms for radiative degradation of p~lycarbonate. '~ Charged Particles [14][15][16] The emission behavior of positively and negatively charged particles is similar to the neutral emission characteristics, as can be expected from their common origin in molecular fracture events. No charged particles were detected during elastic deformation and necking, but at macroscopic fracture, a fast decaying ( a 10 ms) burst of both positively and negatively charged particles was observed.…”