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Paper is the most abundant and inexpensive polymeric structure of cellulose available. Paper has micro-porous capillary-like networks which are responsible for flow of solvents instead of pumps or electronic power, making paper an ideally usable tool. Microfluidic paper-based analytical devices use fabricated paper devices on which hydrophilic zones are formed within hydrophobic barriers. Hydrophilic zones act as regions for actual analytical purposes, whereas hydrophobic zones act to demarcate separate zones from one another. Clinically, these devices have been proved to be excellent point-of-care-devices in diagnosis which can bypass use of costly and time-consuming laboratory techniques. In the presented review, the basic principles and components involved in the design of paper-based devices were then summarised in understandable manner. Further, various applications in different fields were also compiled in the form of text under different sections and tables. Paper-based analytical devices may serve as an excellent tool in variety of analytical works as these techniques are simple, rapid, economic, and require less human power or trainings. They have prominent applications in analysis of biological fluids, drugs/metabolites, food stuffs, colorants, biomarkers, and several other fields.

In the tourism industry, the sales of local specialties is an important part, and the package design and integrity of the specialties are very important. This paper first introduced the support vector machine (SVM) algorithm that was used for detecting defects on the surface of paper packages. Then, the design of red wind packages was briefly described, and the simulation experiment was carried out on SVM algorithm using red wine packages with different degrees of surface defects. Proper parameters were tested using the k-fold cross-validation method. The results demonstrated that the properties of paper improved the value of packages and the SVM algorithm had better accuracy than artificial recognition in recognizing different degrees of defects on the surface of packages. In conclusion, this paper describes the application of paper in packages and provides an effective method for the defection of defects on the surface of packages. This study provides an effective references to the improvement of package values and the enhancement of package integrity.

We developed a surfactant-free spray coating process to coat commercial cellulose-based paper with carbon nanotubes (CNTs) and prepared paper-CNTs current collectors for Li-ion batteries (LIBs). The paper-CNTs were used as current collectors for replacing conventional aluminum foil. Li-ion batteries assembled using paper-CNTs were coated with LiFePO4 as the active material and used as cathodes with Li as the anode, and the assembled LIBs showed a high energy density of 460 Wh kg−1 at a power density of 250 W kg−1. These electrodes were stable even at a current density as high as 600 mA g−1, and showed cycling stability for ~450 cycles at 150 mAh g−1. Furthermore, paper-CNTs based electrodes showed ~17% improvement in areal capacity compared to commercial aluminum-based electrodes suggesting that paper-CNTs can readily displace Al foils as current collectors.

The attractive structural and mechanical properties of cellulose substrates (paper, cloth, and thread), including passive fluid transport, biocompatibility, durability, and flexibility, have attracted researchers in the past few decades to explore them as alternative microfluidic platforms. The incorporation of electrochemical (EC) sensing broadened their use for applications such as clinical diagnosis, pharmaceutical chemical analyses, food quality, and environmental monitoring. This article provides a review on the microfluidic devices constructed on paper, cloth, and thread substrates. It begins with an overview on paper-based microfluidic devices, followed by an in-depth review on the various applications of EC detection incorporated on paper-based microfluidic devices reported to date. The review on paper-based microfluidic devices attempts to convey a few perspective directions that cloth- and thread-based microfluidic devices may take in its development. Finally, the research efforts on the development and evaluation, as well as current limitations of cloth- and thread-based microfluidic devices are discussed. Microfluidic devices constructed on paper, cloth, and thread substrates are still at an early development stage (prototype) requiring several improvements in terms of fabrication, analytical techniques, and performance to become mature platforms that can be adapted and commercialized as real world products. However, they hold a promising potential as wearable devices.

A series of 2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) was prepared by the reaction of chitosan with glycidyl trimethyl ammonium chloride. Structure of HACC was characterized by FT IR and 1H NMR spectroscopies, and it was proved that substitution reaction mainly occurs on the N element. Antimicrobial activities of HACC was examined against S. aureus, E. coli, and A. niger. Results indicatd that the inhibitory effects of HACC solutions were varied with HACC concentration, quaternization degrees, pH values, metal ions, and heat treatment. The antimicrobial properties of handsheets prepared from HACC were studied by the inhibition zone method, and the sheets had good antimicrobial properties against S. aureus and E. coli, and low inhibition rate against A. niger.

A series of 2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) was prepared by the reaction of chitosan with glycidyl trimethyl ammonium chloride. Structure of HACC was characterized by FT IR and 1H NMR spectroscopies, and it was proved that substitution reaction mainly occurs on the N element. Antimicrobial activities of HACC was examined against S. aureus, E. coli, and A. niger. Results indicatd that the inhibitory effects of HACC solutions were varied with HACC concentration, quaternization degrees, pH values, metal ions, and heat treatment. The antimicrobial properties of handsheets prepared from HACC were studied by the inhibition zone method, and the sheets had good antimicrobial properties against S. aureus and E. coli, and low inhibition rate against A. niger. [ABSTRACT FROM AUTHOR]

Twenty three paper based packaging materials commercially used for food packaging in the Czech Republic were analysed with regard to 2-phenylphenol (OPP) content using HPLC technique with fluorimetric detection. The HPLC method was modified with the aim to increase its sensitivity. OPP was detected in quantities ranging from 10 mg kg to 527 mg kg in twenty tested samples. The level of OPP in packaging materials was in close correlation to the content of recycled pulp in used paper material. The migration of OPP from two packaging materials comprised of paperboard coated with low density polyethylene (LDPE) into food simulants was determined at 40°C for 10 days. The levels of migration into 3% acetic acid, 10% ethanol and olive oil were below the limit of detection of used analytical procedure. In the case of 95% ethanol, 13% and 21% of OPP present in tested samples were transferred into simulant. The found occurrence of OPP in paper packages does not pose any significant safety risk for food consumer, but OPP could be considered as wide spread contaminant in paper materials. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Typically, the ash from incineration of paper sludge contains a high percentage of Ca in the form of anorthite (CaAl2Si2O8) and gehlenite (Ca2Al2SiO7). The Ca in the sludge originates from calcite that is included in paper as fillers. We applied acid leaching with HCl on the ash to reduce its Ca content. Zeolite was then synthesized from the leached ash through reaction with 2.5 M NaOH solution at 80 °C for 24 hours. The fraction of Ca and Al extracted from the ash correlates with the pH of the leachant. We determined the leachant pH (after 24 hours of leaching) associated with the Ca: Al:Si ratio in the leached ash that provided optimal production of zeolites with high cation-exchange capacity. During acid leaching, gehlenite dissolved out at higher pH than anorthite. In the case of pH > 5, both gehlenite and anorthite remained in the ash, and hydroxysodalite and LTA (Linde Type A) were synthesized in the product. In the case of pH = 1-5 in the leachant, gehlenite dissolved out but anorthite remained in the ash, and LTA and Na-P1 (zeolite-P) were produced. In the case of pH < 1, both gehlenite and anorthite dissolved out, and only Na-P1 was produced. The cation-exchange capacities of the products that contained hydroxysodalite, LTA, and Na-P1 were approximately 130, 200, and 120 cmol/kg, respectively. We conclude that acid leaching of paper sludge ash controls which of the three zeolite phases form, and that LTA and Na-Pl exhibit a higher cation-exchange capacity than hydroxysodalite. The most efficient production of zeolites with high cation-exchange capacity (about 220 cmol/kg) is obtained after leaching the sludge ash in solutions of around pH = 3. At this low pH, gehlenite has already dissolved out of the sludge ash, half the Ca content of the ash has been leached out, Si has not yet been leached, but Al has begun to be leached. After ash zeolitization, LTA coexists with Na-Pl in t... [ABSTRACT FROM AUTHOR]