ABSTRACT
Electrically conductive cellulose nanopapers (EC-CNPaps) were fabricated by the droplet-coating of multiwall carbon nanotubes (MWCNTs) on cellulose nanopapers (CNPaps), and the effects of the process factors on the electrical conductivity of EC-CNPaps were investigated. The type of CNPaps (made of softwood nanofibrillated cellulose or bacterial cellulose nanofibres), the drying methods of CNPaps (air drying, freeze drying, and oven drying), the applied method for the stabilisation and the concentration of MWCNT-water solutions, and the droplet-coating temperatures (≈23 °C and ≈60 °C) were the examined variable factors. Overall, the oven-dried nanofibrillated cellulose paper as a substrate, 0.1 wt. % of the gum Arabic stabilised MWCNT-water solution ink, and the droplet coating at 60 °C were introduced as the optimum conditions of the examined process factors in this study.
ABSTRACT
The papers have a porous structure which can be a suitable medium for the growth of bacteria. Therefore, in the sanitary papers, creation of a suitable antibacterial property is necessary. In this way, the plant extracts were prepared using solid-liquid extraction method from the Rosmarinus officinalis, Olea europaea, Mentha spicata and Punica granatum. Relatively, the total phenol and flavonoid contents were determined according to colorimetric method. Their antioxidant activity was evaluated using DPPH method. The extracts were sprayed on the surface of the handsheets, and then their antibacterial activity was investigated. The results showed that extracts from the P. granatum has the highest phenol (5.82%) and antioxidant activity (71.13%), while the extract from the R. officinalis had the highest flavonoid (4.23%) and antibacterial activity (90.43%). Hence, it can be concluded that these two extracts could be the suitable combinations to create desirable antibacterial properties in the manufacture of papers with sanitary purposes.
Subject(s)
Anti-Bacterial Agents/pharmacology , Antioxidants/pharmacology , Paper , Plant Extracts/chemistry , Plant Extracts/pharmacology , Anti-Bacterial Agents/chemistry , Antioxidants/chemistry , Drug Evaluation, Preclinical/methods , Flavonoids/analysis , Flavonoids/chemistry , Lythraceae/chemistry , Mentha spicata/chemistry , Olea/chemistry , Phenols/analysis , Phenols/chemistry , Rosmarinus/chemistryABSTRACT
Cellulose fibers were fibrillated using mechanical beating (shearing refiner) and ultra-fine friction grinder, respectively. The fibrillated fibers were then used to make paper. Mechanical beating process created a partial skin fibrillation, while grinding turned fiber from micro to nanoscale through nanofibrillation mechanism. The partially fibrillated and nano fibrillated fibers had significant effects on paper density, tear strength, tensile strength and water drainage time. The effect of nanofibrillation on paper properties was quantitatively higher than that of mechanical beating. Paper sheets from nanofibrillated cellulose have a higher density, higher tensile strength and lower tear strength compared to those subjected to mechanical beating. Mechanical beating and nanofibrillation were both found to be promising fiber structural modifications. Long water drainage time was an important drawback of both fibrillation methods.
