272 JOURNAL OF COSMETIC SCIENCE distorted elastoplastically, with negligible cracking and acoustic emissions prior to failing. More simply, failure in neat polymer films was catastrophic, in which mechanical stresses were rapidly released in conjunction with the liberation of a few large-magnitude acoustic emissions (90–97 dB-SPL) (see Figure 7A and C). In comparison to neat films, the average acoustic emissions produced by fracture events in film-fiber composites were 16 to 32 times lower in perceived volume (40–60 dB-SPL). Put Table II Summary of Acoustic and Mechanical Work Events for Film Composites Testing (50% RH) Polymer #AED (neat) #AED (virgin) #AED (bleached) AVG work (neat, g·mm) AVG work (virgin, g·mm) AVG work (bleached, g·mm) poly(VP/DMAPMA) 3 ± 1 90 ± 22 143 ± 35 53,320 ± 3,023 13,036 ± 1,828 12,521 ± 1,471 poly(VP/MAPTAC) 5 ± 2 60 ± 25 139 ± 34 41,249 ± 3,122 8,082 ± 603 4,181 ± 866 PVP K-120 2 ± 1 99 ± 18 219 ± 38 32,058 ± 1,347 12,080 ± 1,347 9,763 ± 1,129 PVP K-90 6 ± 2 102 ± 8 203 ± 19 20,113 ± 3,269 8,015 ± 1,269 6,181 ± 627 PVP K-60 5 ± 3 166 ± 3 288 ± 64 18,593 ± 1,652 5,847 ± 1,027 5,701 ± 349 PVP K-30 17 ± 4 215 ± 29 568 ± 53 12,819 ± 268 2,560 ± 207 5,285 ± 457 PVP K-30/PEG-400 6 ± 1 520 ± 20 764 ± 32 8,342 ± 233 2,540 ± 137 4,018 ± 35 Imidized p(IB/MA) 27 ± 4 846 ± 64 866 ± 52 495 ± 83 2,505 ± 75 2,523 ± 75 PVP K-15 3 ± 1 611 ± 88 983 ± 68 478 ± 69 1,459 ± 90 1,507 ± 273 Figure 5. Force-against-time curves for film rupturing experiments demonstrate the effect of the number of virgin snippets on the poly(OAA/Acrylates/BAEM) composite film strength. The downward arrows are used to highlight the force response of neat film domains, which appear as secondary peaks in the force-against- time plot for composites constructed with 100 snippets.

273 Enviromechanical Assessment Figure 6. SEM fractographs reveal rupture patterns in brittle and elastoplastic neat fixative films. Brittle failure with smooth fractured surfaces was observed in PVP K-30 (A,B), whereas plastic deformation with jagged fractured crevices was noted in the poly(VP/DMAPMA) film (C,D) (50% RH). Figure 7. Overlay of force and AED responses for (A) PVP K-15 neat film (B) PVP K-15 virgin fiber composite film (C) PVP K-120 neat film and (D) PVP K-120 virgin fiber composite film. The force trace is in blue and individual #AED events are represented by discrete red vertical lines. Note that numerous AED events in (C) and (D) were produced by friction between the composite and probe after the film had ruptured. The integrated area beneath the force-versus-time trace is proportional to the mechanical work required to rupture the film.