Adsorption of a silicone‐based surfactant on polyethylene and polypropylene surfaces and its tribologic performance

Aqueous silicone‐based surfactants are widely used in the processing of synthetic fibers in textile industries since they enhance a number of functional and processing properties. In this paper the interactions between silicone‐based surfactants and textile‐relevant surfaces (polyethylene and polypropylene) were investigated by quartz crystal microbalance with dissipation and the tribologic performance was evaluated by lateral force microscopy. Our results showed that the more hydrophobic polypropylene surface had higher affinity with silicone‐based lubricants than polyethylene surface. These adsorbed layers provided lubricity in textile materials when subject to shear forces and offered protection to wear and abrasion. This is explained by the fact that the hydrophobic groups in the surfactant molecules interact more effectively with the polypropylene surface via hydrophobic forces. This information will ultimately help to further our understanding on lubrication phenomena in fiber processing. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40838.     

A viewpoint on the gastrointestinal fate of cellulose nanocrystals

BackgroundCellulose nanocrystalline (CNC) particles possess unique functional properties such as vastly modifiable surface, considerable mechanical strength and acid resistance, as well as, high aspect ratio. CNCs have received great attention for application in diverse fields of technology including (composite) hydrogels fabrication for the gastric protection and enteral delivery of drugs and nutraceuticals.Scope and approachThe orogastrointestinal digestibility and absorbability of the orally administered CNCs is overviewed in the current article. At first, some surface charge-related characteristics of acid-isolated CNCs are communicated. Then, the biocompatibility and biodegradability of CNCs and CNC-reinforced hydrogels are reviewed, followed by presenting credible digestion and absorption scenarios. Finally, the post-absorption metabolism of CNCs is briefly debated.Key findings and conclusionsBacterial cellulose shows good biocompatibility and hemocompatibility. CNC oxidation provides biologically beneficial impacts; for instance, the TEMPO- and periodate-oxidized CNCs have been shown to regulate some blood metabolic variables and improve the degradability in simulated human blood plasma, respectively. Spherical and carboxyl-bearing cellulose nanoparticles can be isolated through ammonium persulfate digestion. The sphericity of particles results in faster cellular uptake. Negatively-charged CNCs are non-mucoadhesive and thus upon ingestion can penetrate into the buccal and intestinal mucosa. One may augment the absorption of CNCs by targeted receptor-mediated endocytosis. It was postulated that sodium bicarbonate secretion into the duodenum can alter CNCs surface chemistry and influence CNC interaction with gut microbiota.     

Spherical carbons: Synthesis,characterization and activation processes

Spherical carbons have been prepared through hydrothermal treatment of three carbohydrates (glucose, saccharose and cellulose). Preparation variables such as treatment time, treatment temperature and concentration of carbohydrate have been analyzed to obtain spherical carbons. These spherical carbons can be prepared with particle sizes larger than 10 μm, especially from saccharose, and have subsequently been activated using different activation processes (H₃PO₄, NaOH, KOH or physical activation with CO₂) to develop their textural properties. All these spherical carbons maintained their spherical morphology after the activation process, except when KOH/carbon ratios higher than 4/1 were used, which caused partial destruction of the spheres. The spherical activated carbons develop interesting textural properties with the four activating agents employed, reaching surface areas up to 3100 m²/g. Comparison of spherical activated carbons obtained with the different activating agents, taking into account the yields obtained after the activation process, shows that phosphoric acid activation produces spherical activated carbons with higher developed surface areas. Also, the spherical activated carbons present different oxygen groups’ content depending on the activating agent employed (higher surface oxygen groups content for chemical activation than for physical activation).     

Intelligent release of cinnamon oil from engineered proteoliposome via stimulation of Bacillus cereus protease

Inspired by the hydrolysis of casein by protease, a new approach to deliver antimicrobials against bacterial infections was developed in this study. As a natural antibacterial agent, cinnamon oil was encapsulated into engineered liposomes inlaid with casein. The average particle size of proteoliposomes was 615.0 nm and their entrapment efficiency (EE) was 40.0%. In this work, Bacillus cereus (B. cereus) was chosen as model bacterium. The controlled release of liposome-encapsulated cinnamon oil was realized via bacterial protease secreted from B. cereus. As a result, 99.99% of the bacteria could be efficiently inhibited in rice and wheat flour.     

Synthesis and characterization of zirconia-based catalyst for the isomerization of n-hexane

Sulfated zirconia is a very strong solid acid catalyst which can be utilized for various reactions. The present study focuses on synthesis of zirconia-based catalyst with high acidity and high surface area, particularly for isomerization reaction. Sulfated zirconia has been obtained by sulfation of zirconia prepared by hydrothermal route. The catalyst was developed by impregnating tungstophosphoric acid on sulfated zirconia by wet incipient method. The catalyst was characterized through Brunauer–Emmett–Teller (BET) surface area, temperature-programmed desorption of ammonia, temperature program reduction of hydrogen, Fourier transmission infrared spectroscopy, and thermogravimetric analysis. The results revealed that the catalyst is crystalline in nature with surface area 190–225?m² g^?1 and acidity 0.135–0.558?mmol?g^?1. Twenty-five percent conversion was obtained (as confirmed by gas chromatography) at 225°C using n-hexane as model hydrocarbon in fixed-bed microreactor.     

Determination of peroxygen species present in pulp fiber matrixes

A new chromatographic method for the determination of oxidants, such as peroxyborates and peroxides, present in a pulp matrix has been developed. The new method is characterized by its high reproducibility, its low limit of detection, and its high selectivity. Thioanisole (methylphenyl sulfide) is shown to selectively and quantitatively react with oxidants that are present within a pulp matrix. The experimental protocol proposed requires an HPLC system with a normal-phase column. The method allows for the quantitative monitoring of the thioanisole starting material, as well as the products of oxidation, methylphenyl sulfoxide and methylphenyl sulfone. After a 2-day reaction period, the analysis time for a sample is less than 20 min. The detection limit is 2.7 × 10(-6) M for the sulfoxide and sulfone and less than 5.0 × 10(-7) M for the thioanisole. This novel approach for monitoring oxidants present on solid lignocellulosic matrixes may provide pulp and paper manufacturers with a new tool for the study of the long-term bleaching effectiveness of peroxy-containing chemical additives.     

Fouling tendency of ash resulting from burning mixtures of biofuels. Part 1: Deposition rates

Specified mixtures of peat with bark and peat with straw were burned in a lab-scale entrained flow reactor that simulates conditions in the superheater region of a conventional biomass-fired boiler. The deposition rates were recorded on an air-cooled probe that was inserted into the reactor at the outlet. For both mixtures, the deposition behaviour followed a non-linear pattern, which suggests that physico-chemical interaction between the types of ash has taken place. Peat seems to act as a cleansing agent in all mixtures with straw, while it acts as a cleansing agent in mixtures with bark only up to a share of 50 wt% bark. Between 50 and 100 wt% bark, it seems that peat adds to the deposition. The results indicate that it is possible to burn up to 30 wt% bark (renewable biofuel and pulp mill waste) and up to 70 wt% straw (renewable biofuel and agricultural waste) in mixtures with peat (CO₂-neutral fossil fuel) without encountering increased deposition rates.     

Direct lattice imageing in single crystals of isotatic polystyrene

Lattice lines with 1.1 nm and 0.55 nm spacings were resolved in isotactic polystyrene (i-PS) single crystals using a conventional transmission electron microscope, equipped for low dose imageing. It is suggested that these crystals may be used as a model for the direct imageing of structural defects in polymer crystals.     

A simple system to rapidly monitor activated sludge health and performance

A set of four assays designed to rapidly measure the health and biodegradative performance of pulp and paper mill activated sludges was developed. Three of the assays are specific oxygen uptake rates (SOURs) that measure the normal "working" aeration tank BOD (biochemical oxygen demand) removal rate (SOURAT), a near-maximum BOD removal rate (SOURNMAX), and a rate (SOURTOX) used in combination with the SOURNMAX to indicate the presence of toxic or inhibitory substances. The fourth assay is the specific adenosine triphosphate (SATP) content of the sludge, used as a measure of its viable cell content. Fresh biomass (sludge) samples from one laboratory reactor and four mill biotreatment systems were fed raw mill effluents and used to evaluate the four-assay set. The SOURAT values of all systems were 10-40% of their SOURNMAX values: thus the SOURAT:SOURNMAX ratios indicate that each system's free biodegradative capacity was far greater than its operating rate. It was demonstrated using phenol that the SOURNMAX:SOURTOX ratio can indicate the presence of substances toxic or inhibitory to the biomass. The results also indicated that the SOURNMAX is a much better indicator of improving or worsening sludge performance and capacity than the SOURAT. SATP was shown to be a useful monitor of the proportion of viable cells in an activated sludge and a toxicity indicator complementary to the SOURNMAX:SOURTOX ratio and similar in principle to the commercial Microtox toxicity test. This four-assay set was also applied to three practical situations: (a) at-mill monitoring of a biotreatment system; (b) effects of cold storage on biomass; and (c) effects of decreased BOD loading on biomass.