INFORMAZIONI SU QUESTO ARTICOLO

Cita

Fig. 1.

Structural formula of: a) PHMB-SCN; b) PHMB-BS
Structural formula of: a) PHMB-SCN; b) PHMB-BS

Fig. 2.

TGA (a) and DTG (b) of PHMB-BS
TGA (a) and DTG (b) of PHMB-BS

Analysis of FTTR bands corresponding to individual vibrations in the tested samples

Wave number (cm−1) Chemical bond or group Type of chemical compound Type of vibration
3318 N-H Amine (biguanide) Stretch
2934 C-H (alif.) Alifatic hydrocarbons (polyhexamethylene..) Stretch
2060 SCN Nitrile Stretch
1630 C=N Biguanide Stretch
1551 N-H Biguanide Deformation
1381 C-O Carboxylate anion Stretch (symetric)
1153 C-O Carboxylate anion Stretch (asymetric)
719 C-H (arom.) Monosubstituted aromatic ring Deformation

Thermal stability of PHMB-BS

Temperature range (°C) Maximum decomposition temperature (°C) Weight loss (%)
111-175 125 9.82
175-300 287 26.46
300-400 365 22.18
400-500 482 36.89

The results of the antibacterial activity of the tested films against E. coli

Type of bacteria Sample A Assessment
E. coli PE/PHMB-BS 3.9 Very good effect
S. aureus PE/PHMB-BS 3.1 Very good effect

The results of the antibacterial activity of the tested films against E. coli and S. aureus

Type of bacteria Sample A Assessment
E. coli PHMB-SCN 1.73 Satisfactory
PHMB-BS 1.49 Satisfactory
S. aureus PHMB-SCN 2.41 Good
PHMB-BS 3.00 Very good effect

Extruder zone temperatures

Zone 1 Zone 2 Zone 3 Three-wire head
T (°C) 150 160 170 180

Criterion for assessing the effectiveness of the antimicrobial activity

The effectiveness of the antibacterial action A
Poor A<1
Satisfactory 1≤A≤2
Good 2≤A<3
Very good A≥3

Extruder zone temperatures and the processing parameters

Zone 1 Zone 2 Zone 3 Flat-slot head
T (°C) 170 170 165 160
Screw rotation (1/min) 100
Film width (mm) 160
Film thickness (mm) 0.08-0.085