Page 56 - GHES-1-2

Global Health Econ Sustain Antimicrobial eco-friendly material

45.3, 58.6, and 65.7 g%) using a Krüss DSA 100 drop-shape A
analyzer (Matthews, NC, USA) at time intervals of 0, 1, and
3 min. The distance between the water droplet and the film
was fixed at 1 cm.
2.8.2. Fourier transmittance infrared-attenuated total
reflection (FTIR-ATR)
Infrared spectroscopy was performed using a Perkin-
Elmer Spectrum 100 equipped with a diamond-tipped
DiCompTM Crystal ATR (Norwalk, CT, USA). A total of 16
-1
-1
scans were recorded over a range from 4000 cm to 650 cm .
The acquired data were normalized and baseline-corrected. B
Spectra were analyzed from different samples, including BP
(0 g%), BP-g-4VP (6.2, 32.4, and 96.4 g%), and poly(4VP).
2.8.3. Thermogravimetric analysis (TGA)
TGA was carried out using a TGA Q50 from TA
Instruments (New Castle, DE, USA). The heating rate was
set at 10°C/min under a nitrogen atmosphere. Prior to
analysis, samples were dried in an oven at 60°C for 48 h.
Thermograms were obtained for pristine BP, poly(4VP),
@
BP-g-4VP (32.4 g%), and BP-g-4VP (32.4 g%) Ag. The
native software was used to determine decomposition
temperatures (TD) and residue.

3. Results and discussion Figure 2. 4VP grafted onto BP under an inert atmosphere. Experiments
were carried out in MeOH as a solvent and irradiated at room temperature.
The modification of the BP and BP-g-4VP films consisted (A) Graft as a function of the dose and (B) as a function of the monomer
of a two-step process. First, the 4VP monomer was grafted concentration.
onto the films, and then the Ag-modified film was loaded to
obtain the final product BP-g-4VP Ag. The results of these degrees. In addition, even a relatively low dose of 10 kGy
@
modifications and the evaluation of their antimicrobial was sufficient to achieve graft degrees exceeding 20%.
activity in Kirby-Bauer tests are analyzed in detail in this For the intended purposes and in terms of reaction
section. efficiency, low doses and concentrations are preferred. The
aforementioned results showed that the grafted BP-g-4VP
3.1. Results of 4VP grafting films exhibited superior hydrophilic properties compared
Before the grafting process, the samples were washed to to the pristine BP material, as further described in the
remove the MeOH-soluble impurities and retained water, section discussing swelling behavior.
as these factors can affect the polymerization with 4VP 3.2. FTIR-ATR analysis
(Figure S1). The samples were then exposed to gamma
radiation at a mean dose rate of 8.85 ± 0.10 kGy/h and Spectroscopic differences were first observed between
absorbed doses of 10, 20, 30, 40, and 50 kGy, respectively, unwashed BP (directly obtained from the supplier) and
using the direct method. This method involves the washed BP. In the washed BP, the signal of OH chemical
-1
-1
simultaneous exposure of the monomer BP to gamma rays groups between 3500 cm and 3250 cm weakened, which
under inert atmosphere conditions, at room temperature, can be attributed to the elimination of additives and/or
using 4VP/MeOH solutions of 10, 25, 50, and 75 vol%, as water, possibly a plasticizer (usually containing OH groups).
well as solvent-free 4VP at 100 vol% conditions. A total Water is indeed a part of the structure (Figure S2A).
of five series of five experiments at different doses and For this reason, all samples were washed before being
monomer concentrations were conducted to determine grafted. In addition, as a reference, the poly(4VP) spectrum
the graft% to obtain an optimal BP-g-4VP, as illustrated clearly differentiates the signals corresponding to the
in Figure 2. The results revealed that increasing the dose grafting process from those of BP. Although poly(4VP) had
yielded higher graft degrees, especially at concentrations been dried in the oven at 60°C for 24 h, the analyzed sample
equal to or >50 vol%, even exceeding 100% of graft displayed a strong signal at 3246 cm , which corresponds
-1

Volume 1 Issue 2 (2023) 4 https://doi.org/10.36922/ghes.1251