Enhanced thermal and mechanical properties by cost-effective carboxylated nanodiamonds in poly (vinyl alcohol)

Abstract

In this study, the high-energy ball-milled nanodiamonds (MNDs) are carefully treated with low-temperature annealing and mixed acids to obtain carboxylated MNDs (cMNDs). This process not only removes impurities but also grafts oxygen containing functional groups onto MNDs surfaces. Then poly (vinyl alcohol) (PVA)/cMND nanocomposites are prepared by a facile aqueous solution casting method. Compared with PVA/MND, an improved dispersion of nanoparticles in the matrix and higher nanoparticles content can be achieved by PVA/ cMND. It is found that glass transition temperature (T g) and loss factor peak temperature (T tand) of PVA/cMND nanocomposites are both shifted to higher values than pure PVA. Thermal decomposition of PVA is obviously suppressed by cMNDs. The onset and maximum decomposition temperatures increases by over 17 C and 24 C, respectively. The thermal conductivity increases by 57.5%. Furthermore, tensile strength and Young's modulus of PVA are improved by 62.3% and 166.7% with the addition of cMNDs.

Fabrication and Biocompatibility Evaluation of Nanodiamonds-Gelatin Electrospun Materials Designed for Prospective Tissue Regeneration Applications

“…As expected, no significant differences were observed between the simple FG and FG_ND 0.5% solutions, but for FG_ND 1% precursor 2.3 times increase of the viscosity was recorded. The behavior could be explained due to interactions between the functional groups from the surface of NDs and the functional groups of the gelation macromolecules, in accordance with other studies [35,36,45]. The effect of the NDs can be slightly observed on the increased hydrophobicity of FG_ND 1% material.…”

“…In order to avoid the common tendency of the NDs to create aggregates, we have used a mild sonication treatment of the NDs dispersions in aqueous FG solutions during the obtaining of the fibers’ precursors. Consistent with previous researches [35,36], the rheological characterization of the precursors provided information regarding the viscosity of the mixture. As expected, no significant differences were observed between the simple FG and FG_ND 0.5% solutions, but for FG_ND 1% precursor 2.3 times increase of the viscosity was recorded.…”

“…The FG_ND 1% composition presented higher viscosity compared to the samples FG and FG_ND 0.5%. One could explain this behavior as a consequence of both the increased concentration of the nanospecies within the solution, but also as a consequence of the higher amount of hydrogen bonds formed between the functional groups at the surface of the nanoparticles with the functional groups from the backbone of gelatin (NH 2 , COOH, OH) [35]. Moreover, another interesting aspect resulted from the measurements for FG_ND 1% is represented by the small tendency of decrease of the viscosity with increasing the shear rate (values over 80 s −1 ).…”

Safety assessment of new nanodiamonds@corrole hybrids addressed by the response of RAW-264.7 macrophages

“…1a) is in line with the results reported in literature. 35 The presence of the carboxylic group is highlighted by the peak at 1730 cm À1 and by the broad band centered at 3380 cm À1 , corresponding to the stretching of the CQO and O-H bonds, respectively. This broad band at high frequencies can also have a contribution from adsorbed water.…”

The influence of blend composition and filler on the microstructure, crystallization, and mechanical behavior of polymer blends with multilayered structures

“…As well known, the composition ratio is also a key issue for the fabrication of multilayered structures, because it can largely effect the microstructure and properties of these materials. Meanwhile, the addition of fillers can also influence the structure of these materials and bring interesting functionalities to the final product [32][33][34][35][36][37]. Hence, current investigation is focused on the influence of blends composition ratio and the addition of fillers on the formation of multilayered structures.…”