Search

A critical challenge in the preparation of reinforced polymer nanocomposites is to prevent the aggregation of nanofillers. In this work, a novel poly(γ-benzyl-L-glutamate) (PBLG)-modified silicon dioxide@graphene oxide nanofiller (SiO2@GO-g-PBLG) was prepared via a continuous electrostatic complex and ring-opening polymerization (ROP) method. The grafted PBLG prevented the aggregation of SiO2 nanoparticles and GO sheets, realized the colloid stability of SiO2@GO-g-PBLG in organic solvents, and thus increased its phase interaction in a polymer matrix. The hybrid nanofiller greatly enhanced the mechanical properties of poly(L-lactide) (PLLA). As a typical feature, the tensile strength of PLLA nanocomposites with only 5 wt% of SiO2@GO-g-PBLG was 88.9 MPa, about 45% higher than that of pure PLLA. In addition, the hybrid nanofillers also have some positive effects on improving the thermal stability of PLLA. Therefore, SiO2@GO-g-PBLG was a promising hybrid nanofiller to reinforce polymers such as PLLA.

Conjugated microporous polymers (CMPs) are usually obtained as amorphous or semicrystalline powders. Their insolubility and nonprocessability are considered as key bottlenecks that impede CMP applications. In this study, light-emitting, nanofibrous films were fabricated by electrospinning CMP/poly(lactic acid) (PLA) mixtures. The resulting nanofibrous films show a high flexibility combined with high porosity and surface-area-to-volume ratios. The CMP-based nanofibrous films have been used as sensitive sensors in the detection of nitroaromatic and benzoquinone vapors as well as oxidizing metal ions. Moreover, 4-iodophenyl-substituted graphene sheets were used as templates for growing CMP/graphene sandwiches. The graphene-based CMP (G-CMP) sandwiches are characterized by high surface areas and aspect ratios. Furthermore, hierarchically porous two-dimensional carbon nanosheets were obtained by pyrolysis of these carbon-rich G-CMP hybrids. The resulting carbon nanomaterials show excellent supercapacitor behav...

In order to tune the surface properties of hydroxyapatite(HA) nanoparticles and prevent them from aggregation, an efficient method was proposed to graft chitosan(CS) molecules on the surface of HA via “click” reaction. Thermal gravimetric analysis(TGA) shows that CS was successfully grafted on the surface of HA nanoparticles and the grafting amount was about 8.9 g of CS on per hundred grams of HA. The grafted chitosan chains can prevent HA nanoparticles from aggregation and greatly enhance the colloidal stability of HA in water. The 3-(4,5-dimethylthiazoyl-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay demonstrats that the cytotoxicity of CS modified HA(HA-CS) is negligible and thus HA-CS may find potential application in biomedical fields.