Ultrathin and Light-Weight Graphene Aerogel with Precisely Tunable Density for Highly Efficient Microwave Absorbing.

Graphene aerogel (GA) possessing good electrical conductivity and low weight has been widely considered as a promising candidate for high-performance microwave-absorbing (MA) materials. However, simultaneous realization of high reflection loss (RL), low thickness, and light weight remains very challenging for GA because of the trade-off between impedance match and attenuation ability. Herein, through use of (3-aminopropyl)triethoxysilane as a surface modifier and cross-linker, the GA materials with precisely controlled density are fabricated via a unique solvothermal protocol of zero-volume shrinkage. The density-controlled GA (4.5 mg·cm-3) exhibits a remarkable minimum RL (RLmin) of -50 dB at a thickness of 1.14 mm in the K-band, owing to the optimized dielectric properties. Moreover, even higher attenuation ability without sacrificed impedance match is obtained by incorporating magnetic Fe3O4@C microspheres into the density-controlled GA. Superior MA performance involving unprecedented RLmin of -54.0 dB and qualified bandwidth covering 80% of the K-band has been achieved in the superlight Fe3O4@C/GA composite at a thickness less than 1 mm, which is highly desirable for MA material applied in mobile devices.

Preparation and characterization of poly(L-lactide)-co-poly(trimethylene carbonate)/talc film.

Poly(L-lactide)-co-poly(trimethylene carbonate) (PLLA-PTMC) composites with various talc content as food packaging materials were prepared by solvent casting method. The effect of talc filler loading (0, 1, 2, and 3 wt%) on phase morphology of PLLA-PTMC/Talc composites and improvement in resulting properties were reported. The X-ray diffraction (XRD) patterns and differential scanning calorimetry (DSC) curves indicated that the crystallinity of PLLA-PTMC/Talc composites increased. Fourier transform infrared spectroscopy (FTIR) suggested that there were strong interactions between PLLA-PTMC copolymer and talc filler. The scanning electron microscopy (SEM) image of composite films revealed certain homogeneity between PLLA-PTMC and Talc, when the talc filler did not exceed 3 wt%. The elongation at break of composite films significantly (p<0.05) improved with the addition of talc filler. Furthermore, there were 23%, 31%, and 14% improvement in water vapor barrier properties at 1, 2, and 3 wt% of talc in PLLA-PTMC/Talc composites, respectively. This had been confirmed by thermogravimetric analysis (TGA).

Effect of chitosan film incorporated with tea polyphenol on quality and shelf life of pork meat patties.

The objective of this study was to investigate the effect of chitosan (CH) film incorporated with tea polyphenol (TP) on quality and shelf life of pork meat patties stored at 4±1 °C for 12 days. The microbiological, physicochemical (pH, thiobarbituric acid-reactive substances (TBARS) values, and metmyoglobin (MetMb)), and sensory qualities were measured on all the samples. A microbiological shelf-life extension of 6 days was achieved for CH and CH-TP treatment groups when compared to the control group. Wrapping with CH-TP composite film tended to retard the increases in TBARS values and MetMb content. CH-TP composite film maintained acceptable sensory quality of pork meat patties throughout the storage. The results indicated that CH-TP composite film could be a promising material as a packaging film for extending the shelf life of pork meat patties.