Polymer/boron nitride nanocomposite materials for superior thermal transport performance.

Boron nitride nanosheets were dispersed in polymers to give composite films with excellent thermal transport performances approaching the record values found in polymer/graphene nanocomposites. Similarly high performance at lower BN loadings was achieved by aligning the nanosheets in poly(vinyl alcohol) matrix by simple mechanical stretching (see picture).

Insight into the mechanisms for hexavalent chromium reduction and sulfisoxazole degradation catalyzed by graphitic carbon nitride: The Yin and Yang in the photo-assisted processes.

As robust polymeric catalysts, graphitic carbon nitride (g-C3N4) has been known to have great application potential in environmental remediation. However, the mechanisms in the photo-assisted catalytic processes during the reduction or oxidation of pollutants are still difficult to discern and therefore not well studied. In this work, visible-assisted catalytic reduction of hexavalent chromium (Cr(VI)) or oxidation of sulfisoxazole (SIZ) by g-C3N4 with the addition of formic acid (FA) or potassium peroxydisulfate (PS) were systematically investigated. Effects of operation parameters such as g-C3N4 dosage, FA concentration, Cr(VI) concentration, solution pH, PS concentration were studied. The results showed g-C3N4 can be effective and robust catalyst for both the reduction (Yin) and oxidation (Yang) reactions in the environmental remediation. Mechanisms were studied by using electron spin resonance (ESR) spectroscopy. The results revealed the CO 2- is the predominant radical for Cr(VI) reduction in the g-C3N4/FA/Vis system and the SO4- and OH are all the main radicals for the oxidation of SIZ in the g-C3N4/PS/Vis system. The photo-generated carriers by g-C3N4, act as radical initiator, were responsible for the production of the reactive radical species in aqueous solution. This work not only shed a new light on the application of semiconductor polymers for the removal of micropollutants and also will expand the applicability of the polymeric photocatalysts for environmental remediation.

Preparation and properties of pearl powder/polypropylene composites and their biocompatibility.

To improve the biocompatibility of PP monofilaments used for pelvic reconstruction mesh, natural pearl powders were introduced as fillers in the preparation of modified PP monofilaments. The mechanical properties the modified PP monofilaments were analyzed, followed by characterization by scanning electron microscopy (SEM). Then, the biocompatibilities of these samples were investigated by MTT assay. The results revealed that the tensile strength and elongation of the as-prepared PP monofilaments can satisfy the requirement. According to the SEM images, masses of pearl powder were observed on the surface of monofilaments, which may favor the cell growth. The MTT results and the confocal microscopical images indicated that the presence of pearl powder in PP monofilaments led to improved proliferation and growth of L929 and PIEC cells under the same conditions, suggesting that PP monofilaments modified by pearl powders have a great potential in the applications of pelvic reconstruction.