Polyurethane/Nanosilver-Doped Halloysite Nanocomposites: Thermal, Mechanical Properties, and Antibacterial Properties

Abstract

In this study, the researchers successfully embellished the surface of halloysite (Ag/HNTs) with silver using halloysite, silver nitrate (AgNO3), and polyvinylpyrrolidone (PVP). The researchers then prepared polyurethane that contained pyridine ring by using 4,4′-diphenylmethane diisocyanate (MDI) and polytetramethylene glycol (PTMG) as the hard chain segment and the soft chain segment of polyurethane (PU), as well as 2,6-pyridinedimethanol (2,6-PDM) as the chain extension agent. This was followed by the preparation of Ag/HNTs/PUs nanocomposite thin films, achieved by mixing Ag/HNTs with different ratios into polyurethane that contains pyridine ring. First, the Ag/HNTs powders were analyzed using energy-dispersive X-ray spectroscopy, X-ray diffraction, and transmission electron microscopy. Subsequently, Fourier-transform infrared spectroscopy was used to examine the dispersibility of Ag/HNTs in PU, whereas the thermal stability and the viscoelasticity of Ag/HNTs/PU were examined using thermal gravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. When the mechanical properties of Ag/HNTs/PU were tested using a universal strength tester, the results indicated a maximum increase of 109.5% in tensile strength. The researchers then examined the surface roughness and the hydrophobic ability of the Ag/HNTs/PU thin films by using atomic force microscopy and water contact angle. Lastly, antibacterial testing on Escherichia coli revealed that when the additive of Ag/HNTs reached 2.0 wt%, 99.3% of the E. coli were eliminated. These results indicated that the addition of Ag/HNTs into PU could enhance the thermal stability, mechanical properties, and antibacterial properties of PU, implying the potential of Ag/HNTs-02 as biomedicine material.

Enhanced Piezoelectric Properties of Poly(Vinylidenefluoride-Co-Trifluoroethylene)/Carbon-Based Nanomaterial Composite Films for Pressure Sensing Applications

“…The results revealed the water contact angles of PVDF-TrFE, CNT-COOH/PVDF-T 1 wt%, and CNT-COOH:SMA EF40-M/PVDF-T 1:1 were 80.9, 100.9, and 107.2 • . The results indicated that the contact angle to water has a significant upward trend when CNT-COOH was added to PVDF-TrFE because the carbon nanomaterials are distributed on the surface of PVDF-TrFE when PVDF-TrFE was added with CNT-COOH, thereby increasing the surface roughness, which has been reported in previous studies [32,33]. Subsequently, it can be found that the water contact angle increased from 100.9 to 107.2 • by adding SMA EF40-M, which may be because SMA EF40-M can improve CNT-COOH dispersal in PVDF-TrFE.…”

Preparation and Properties of the Urea-Formaldehyde Res-In/Reactive Halloysite Nanocomposites Adhesive with Low-Formaldehyde Emission and Good Water Resistance

“…In order to solve these problems, it has been reported that mineral powders including nano clay and nano silica are used as UF fillers in scientific research [ 32 , 33 , 34 , 35 , 36 ]. These fillers can prevent the excessive penetration of resin into wood pores, improve the initial viscosity, reduce the internal stress of cured adhesive layer, improve the aging resistance of glued wood-based panels, and reduce the formaldehyde emission [ 37 , 38 , 39 ].…”

Interaction Insight of Pullulan-Mediated Gamma-Irradiated Silver Nanoparticle Synthesis and Its Antibacterial Activity

“…It is known that pullulan (PL) exists in an amorphous state [ 40 ]. The incorporation of Ag-NPs and irradiation techniques was previously shown to transform the solution to exhibit crystallization characteristics [ 41 ]. Four (4) diffraction peaks can confirm the purity of the silver formation at 2θ of 38.54°, 44.91°, 65.04°, and 78.11°, corresponding to the (111), (200), (220), and (311) planes of the face-centered cubic (FCC) structure [ 42 ].…”