Differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and dynamic mechanical analysis (DMA) properties of poly(lactic acid)/ poly(butylene adipate-co-terephthalate) (PLA/PBAT) specimens suggest that only small amounts of poor PLA and/ or PBAT crystals are present in their corresponding melt crystallized specimens. In fact, the percentage crystallinity, peak melting temperature and onset re-crystallization temperature values of PLA/PBAT specimens reduce gradually as their PBAT contents increase. However, the glass transition temperatures of PLA molecules found by DSC and DMA analysis reduce to the minimum value as the PBAT contents of PLA x PBAT y specimens reach 2.5 wt %. Further morphological and DMA analysis of PLA/PBAT specimens reveal that PBAT molecules are miscible with PLA molecules at PBAT contents equal to or less than 2.5 wt %, since no distinguished phase-separated PBAT droplets and tan d transitions were found on fracture surfaces and tan d curves of PLA/PBAT specimens, respectively. In contrast to PLA, the PBAT specimen exhibits highly deformable properties. After blending proper amounts of PBAT in PLA, the inherent brittle deformation behavior of PLA was successfully improved. Possible reasons accounting for these interesting crystallization, compatible and tensile properties of PLA/PBAT specimens are proposed.

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Visible watermarking schemes are important IPR protection mechanisms for digital images and videos that have to be released for certain purposes but illegal reproductions of them are prohibited. Visible watermarking techniques protect digital contents in a more active manner, which is quite different from the invisible watermarking techniques. Digital data embedded with visible watermarks will contain recognizable but unobtrusive copyright patterns, and the details of the host data should still exist. The embedded pattern of a useful visible watermarking scheme should be difficult or even impossible to be removed unless intensive and expensive human labors are involved. In this paper, we propose an attacking scheme against current visible image watermarking techniques. After manually selecting the watermarked areas, only few human interventions are required. For watermarks purely composed of thin patterns, basic image recovery techniques can completely remove the embedded patterns. For more general watermarks consisting of thick patterns, not only information in surrounding unmarked areas but also information within watermarked areas will be utilized to correctly recover the host image. Although the proposed scheme does not guarantee that the recovered images will be exactly identical to the unmarked originals, the structure of the embedded pattern will be seriously destroyed and a perceptually satisfying recovered image can be obtained. In other words, a general attacking scheme based on the contradictive requirements of current visible watermarking techniques is worked out. Thus, the robustness of current visible watermarking schemes for digital images is doubtful and needs to be improved.

Systematically investigations of the plasticizing effects of triacetine (TAc) on crystallization, chain mobility, microstructure, and tensile properties of the Poly (lactic acid)/triacetine (PLA/TAc) blends are reported. A new transition hump was observed on the tan d curve of PLA x TAc y specimens at temperatures ranging from À80 to À20 C. Thermal, wide angle X-ray diffraction (WAXD) and dynamic mechanical analysis properties of PLA and PLA x TAc y series specimens suggest that PLA and PLA xTAc y series specimens can hardly crystallize by cooling the melt in room temperature. However, significant recrystallization of a form PLA crystals was found during the annealing processes of PLA x TAc y series specimens. Some ''less perfect'' b form PLA crystals were found as the TAc contents of PLA x TAc y specimens reach 30 wt %. Further morphological analysis show that the inherent brittle deformation behavior of the PLA specimen was successfully transformed into relatively ductile fracture behavior after blending sufficient but optimum amounts of TAc in PLA resins. Possible reasons accounting for this interesting recrystallization, thermal, microstructure and tensile properties of PLA x TAc y specimens are proposed.

Systemic investigation of the influence of the plain and functionalized carbon nanotube (CNT) contents on the ultradrawing properties of ultrahigh molecular weight polyethylene/carbon nanotubes (UHMWPE/CNTs, FC y ) and UHMWPE/functionalized CNTs (FC fx-y ) as-prepared fibers are reported. In a way similar to those found for the orientation factor values, the achievable draw ratios (D ra ) of the FC y and FC fx-y as-prepared fibers approached a maximum value as their CNT and/or functionalized CNT contents reached their corresponding optimum values. The maximum D ra values obtained for FC fx-0.001 as-prepared fiber specimens prepared at varying maleic anhydride grafted polyethylene (PE -g-MAH )/modified CNTs weight ratios were significantly higher that of the FC 0.0015 as-prepared fiber specimen prepared at the optimum plain CNT content. Tensile property analysis further suggested that excellent orientation and tensile properties of the drawn FC y and FC fx-y fibers can be obtained by ultradraw-ing the fibers prepared at their optimum plain CNT and/or functionalized CNT contents. To understand the interesting orientation, ultradrawing and tensile properties of FC y and FC fx-y fiber specimens, FTIR, specific surface area, and SEM morphology analysis of the plain and functionalized CNTs were performed in this study. POLYM. ENG. SCI., 51:687-696, 2011. ª FIG. 6. Tensile strength and modulus values of FC 0 , FC 0.0005 , FC 0.0001 , FC 0.0015 , FC 0.002 , FC f1-0.0005 , FC f1-0.001 , FC f1-0.0015 , FC f1-0.002 , FC f2-0.0005 , FC f2-0.001 , FC f2-0.0015 , FC f2-0.002 , FC f3-0.0005 , FC f3-0.001 , FC f3-0.0015 , FC f3-0.002 , FC f4-0.0005 , FC f4-0.001 , FC f4-0.0015 and FC f4-0.002 fiber specimens with varying draw ratios.