Study on the pretreatment of poly(ether ether ketone)/multiwalled carbon nanotubes composites through environmentally friendly chemical etching and electrical properties of the chemically metallized composites.

The high-volume resistivity and surface resistance of poly(ether ether ketone)/multiwalled carbon nanotubes (PEEK/MWCNT) composites restrict their use in an electronic field. To decrease the volume resistivity and surface resistance, we metalized the composites by electroless plating. The composites and metal coatings were characterized by SEM, XPS, AFM, EDX, and XRD spectroscopy. The swelling ratio of the composites, volume resistivity of two-side-coated composites, sheet resistance of plated composites, and adhesion between the coating and PEEK/MWCNT were tested. The results are as follows. A high roughness and a small swelling ratio were obtained by swelling in 18 mol/L H2SO4 for 3 min. Most of the MWCNT on the surface were still wrapped with PEEK after swelling. To expose the MWCNT, an environmentally friendly and effective etchant (MnO2-NaH2PO4-H2SO4) was used. After etching, not only were high roughness and partially exposed MWCNT obtained but also the percentage of hydrophilic groups on the surface was increased. A dense cauliflower-like Ni-P coating was produced, and the exposed MWCNT were embedded in the metal coating after electroless plating for 20 min. The coating exhibited an amorphous structure with a phosphorus content of 11.21 wt %. The volume resistivity of two-side-coated PEEK/MWCNT dropped sharply to 38 Ω·m after electroless plating for 5 min. The sheet resistance decreased with increasing the electroless-plating time, and it dropped to 0.88 Ω/square after electroless plating for 40 min. The adhesion of the coating reached the highest 5 B scale (ASTM D3359) and could even undergo the test 20 times.

Morphological and histological analysis on the in vivo degradation of poly (propylene fumarate)/(calcium sulfate/ß-tricalcium phosphate).

Poly (propylene fumarate)/(Calcium sulfate/ß-tricalcium phosphate) (PPF/(CaSO(4)/ß-TCP)) is a kind of biodegradable composite designed for bone tissue engineering. The in vitro degradation behavior of this composite has been investigated in our previous study. The aim of this study was to investigate the effects of PPF molecular weight and CaSO(4)/ß-TCP molar ratio on the in vivo degradation of PPF/(CaSO(4)/ß-TCP) composite and the bone tissue response to PPF/(CaSO(4)/ß-TCP). Total 36 PPF/(CaSO(4)/ß-TCP) composite samples were implanted into 15.0 mm segmental defects in tibiae of 18 Japanese rabbits, harvested at 2, 4 and 8 weeks after the operation, and analyzed using radiographic and histological analysis to assess the in vivo degradation of the composites as well as tissue response to the implants. The in vivo degradation results show that all the samples maintained their original shape. Tissues penetrated into the pores which formed by the degradation of CaSO(4)/ß-TCP spheres near the surface of the composites. The rate of in vivo degradation and pore forming increased with a decrease in PPF molecular weight and an increase in CaSO(4)/ß-TCP molar ratio. No inflammatory reaction was observed after implantation, and the composites are capable of in situ pore forming. In particular, the pore forming rate can be adjusted by varying the composition of the composites. These results may indicate that PPF/(CaSO(4)/ß-TCP) is a promising osteogenic scaffold for its controllable degradation rate and excellent biocompatibility.

Six new glucose esters of 3-nitropropanoic acid from Indigofera kirilowii.

An investigation of the aliphatic nitrocompounds in Indigofera kirilowii resulted in the identification of two new esters of glucose with 3-nitropropanoic acid and acrylic acid - kirilowin C (1) and kirilowin D (2), together with four new glucose 3-nitropropanoates - kirilowins E-H (3-6). Their structures were identified by spectroscopic data.

Acryloylated glucose 3-nitropropanoates from Indigofera kirilowii.

Two unique glucose esters of 3-nitropropanoic acid with acryloyl moieties, kirilowin A and kirilowin B, were isolated from the roots of Indigofera kirilowii. Their structures were elucidated by detailed spectroscopic analysis. The two acrylates constitute new additions to the toxic glucose conjugates of 3-nitropropanoic acid in angiosperms.