Synthesis and characterization of the new cellulose derivative films based on the hydroxyethyl cellulose prepared from “Stipa Tenacissima” cellulose of Eastern Morocco. I. Solubility study

Hydroxyethyl cellulose Acetate (HECA) was prepared starting from hydroxyethyl cellulose (HEC), acetic anhydride and perchloric acid which was used as catalyst. The synthesized product was characterized by FTIR, ¹³C NMR, and ¹H NMR. Substitution degree (DS) of HECA was determined using FTIR spectra taking a classical titration method as reference. The ¹H NMR spectroscopy was also used to confirm the results obtained by FTIR. The DS is substantially affected by the temperature, the time of reaction and especially the equivalent number (eq. nb.) of the acetic anhydride added. We have studied and discussed in the context of usage in modification reactions, the solubility of the HECA samples by varying their DS. This investigation was based on the determination of the Flory‐Huggins interaction parameters (χ_SP) using the partial Hansen solubility parameters (HSP). HSP of HEC and the HECA samples were calculated from the Van‐Krevlen‐Hoftyze (VKH) method and the T. Lindvig approximation. We have focused our work on predicting and controlling family solvents of HECA with various DS, to facilitate and to optimize the homogenous modification reaction conditions. From results on a range of HECA samples, it is conclude that their prediction solubility taking the value of DS into account is possible, and then the surface modification can relatively be easily realized. The thermal analysis study shows some differences in T_g and thermal degradation between HEC and HECA, moreover these thermal temperatures are influenced by DS values. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Physicochemical characterization of celluloses extracted from Esparto “Stipa tenacissima” of Eastern Morocco

Increasing ecological concerns have given rise to renewed interest in the use of natural materials, considering their renewability and possibility of disposal at the end of their life cycle without damage to the environment. In this study, we examined the isolation of cellulose from Esparto “Stipa tenacissima” of Eastern Morocco by two different ways; the first one using an acetic acid solution catalyzed by nitric acid. The objective is to determine the optimum amount of this catalyst needed to the extraction. The second way consists to study the cellulose extraction with change of the alkaline solution concentration in order to choose the required value. The cellulosic samples were characterized by FT‐IR spectroscopy and X‐ray diffraction, the morphology of the isolated fibers was investigated by optical microscopy. Thermal analysis (DT‐TGA) were carried out to study the thermal behavior of the cellulose isolated compared with the control sample. The degree of polymerization (DP) of the samples extracted is estimated from the intrinsic viscosity value using the Mark‐Houwink equation in two different solutions (DMAc/9%LiCl) and (6%NaOH/4%urea/90%H₂O). We have demonstrated that the extraction using an acetic acid solution has been very successful by adding 2% in volume of nitric acid (HNO₃). However, the extraction process using an alkaline solution (NaOH; 1M) is preferable because of the absence of acetylating reaction and the high purity and the nondegradation of the resulted fibers. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

“Pore/bead” membrane for rechargeable lithium ion batteries

A special “pore/bead” membrane was prepared with a mesoporous inorganic filler (MCM‐41) and a P(VDF‐HFP) binder. The special “pore/bead” structure of the MCM‐41 filler not only enhanced the puncture strength of the membrane but also improved its ionic conductivity. The puncture strength of the dried “pore/bead” membrane (MCM‐41 : P(VDF‐HFP) = 1 : 1.5) was 18 N, and showed a slight decrease (16 N) after the membrane was wetted by liquid electrolyte. Additionally, the composite membrane showed excellent thermal dimensional stability. The composite membrane could be activated by adding 1M LiClO₄‐EC/DMC (1 : 1 by volume). The activated membrane displayed a high ionic conductivity about 3.4 × 10^?3 S cm^?1 at room temperature. Its electrochemical stability window was up to 5.3 V vs. Li/Li⁺, indicating that it was very suitable for lithium‐ion battery application. The battery assembled using the composite electrolyte also showed reasonably good high‐rate performance. The approach of preparing a “pore/bead” membrane provides a new avenue for improving both the conductivity and the mechanical strength of polymer electrolytes for lithium batteries. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Treatment of gases and dust using “droplet columns”

The properties of the air-water state diagram, representing the liquid holdups according to gas velocities, in a 0.075 m diameter column are restated. After measurement of the interfacial areas and mass-transfer coefficients, the part of the diagram corresponding to high gas velocities and low liquid contents (10 < U_G < 14 m/s and 0.005 < U_L < 0.04 m/s) was chosen for the treatment of polluted gas streams. Under these conditions, it was shown that a “droplet column” is very efficient for the treatment of gases polluted by acid vapors (SO₂, HCl) and dust (iron oxide, talc, etc.). The cost of energy appeared more favorable than for classical bubble columns.     

Efficient synthesis of zwitterionic sulfobetaine group functional polyurethanes via “click” reaction

A novel polyurethane material containing zwitterionic sulfobetaine groups has been synthesized using the copper‐catalyzed 1,3‐dipolar cycloaddition (azide‐alkyne click chemistry). A standard two‐step polyaddition method was used to produce the well‐defined polyurethane based on polycarbonatediol (PCDL) with alkyne groups. These polyurethanes containing alkyne units were then efficiently clicked using 3‐((2‐azidoethyl)dimethylammonio)propane‐1‐sulfonate (DMPS‐N₃). The novel PU material was characterized by ¹H NMR, Fourier transform infrared (FTIR) spectrometer, gel permeation chromatography (GPC), elemental analysis, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). This facile “click” reaction provides a useful tool for the development of novel functional polyurethanes for biomedical applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Simple “On‐Demand” Production of Bioactive Natural Products

Exchange of the native promoter to the arabinose‐inducible promoter P_BAD was established in entomopathogenic bacteria to silence and/or activate gene clusters involved in natural product biosynthesis. This allowed the “on‐demand” production of GameXPeptides, xenoamicins, and the blue pigment indigoidine. The gene clusters for the novel “mevalagmapeptides” and the highly toxic xenorhabdins were identified by this approach.     

Modeling of “living” free‐radical polymerization processes. I. Batch,semibatch, and continuous tank reactors

A comprehensive mathematical model is developed for “living” free‐radical polymerization carried out in tank reactors and provides a tool for the study of process development and design issues. The model is validated using experimental data for nitroxide‐mediated styrene polymerization and atom transfer radical copolymerization of styrene and n‐butyl acrylate. Simulations show that the presence of reversible capping reactions between growing and dormant polymer chains should boost initiation efficiency when using free nitroxide in conjunction with conventional initiator and also increase the effectiveness of thermal initiation. A study shows the effects of the value of the capping equilibrium constant and capping reaction rate constants for both nitroxide‐mediated styrene polymerization (using alkoxyamine as polymer chain seeds) and atom transfer radical polymerization of n‐butyl acrylate (using methyl 2‐bromopropionate as chain extension seeds). Also the effect of introducing additional conventional initiator into atom transfer radical polymerization of n‐butyl acrylate is studied. It is found that the characteristics of long chain growth are determined by the fast exchange of radicals between growing and dormant polymer chains. Polymerization results in batch, semibatch, and a series of continuous tank reactors are analyzed. The simulations also show that a semibatch reactor is most flexible for the preparation of polymers with controlled architecture. For continuous tank reactors, the residence time distribution has a significant effect on the development of chain architecture. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1630–1662, 2002     

Construction of waste-collagen modified superfine fiber substrates based on “click” chemistry: Moisture absorption and permeability

Superfine fiber synthetic leather is a high-grade artificial leather product with numerous characteristics and advantages. However, compared with natural leather, it shows poor moisture absorption and moisture permeability, and it gives people a hot and tacky feeling; thus, the improvement of these properties has become a popular topic in the industry. In this paper, the “click” chemistry method was employed to modify the nylon fiber of the superfine fiber synthetic leather base with waste collagen to improve the moisture absorption and permeability of the superfine fiber synthetic leather base, thus enhancing the hygienic performance and wearing comfort of the end products, realizing waste recycling. This study obtained the optimal reaction conditions for the “click” modification of unfigured sea-island superfine fiber synthetic leather base with collagen methacrylamide. The characterizations by static contact angle measurements, attenuated total reflection infrared spectroscopy, and X-ray photoelectron spectroscopy analysis confirmed that collagen was successfully grafted onto the surface of the nylon fiber. Compared with the original base, the moisture absorption, and permeability of the base were improved by 602.4% and 43%, respectively. This study shows the theoretical research significance and excellent practical value for the resource utilization of skin collagen waste.     

A similarity‐based cross‐language comparison of basicness and demarcation of “blue” terms

To investigate linguistic and perceptual boundaries within the “blue” region of the color gamut, we analyzed sorting data from speakers of six languages who sorted color stimuli by similarity. Two of these languages, Russian and Italian, are thought to have a separate basic color term and category for “light blue,” distinguishing it from “blue,” and the third was English, which lacks this distinction. There has been less study of the possible basicness of “light blue” terms in the other three languages: Lithuanian and Estonian (both spoken in Baltic states) and Udmurt (a linguistic enclave in North Russia). Sorting data from each sample of speakers were analyzed with principal component analysis and multidimensional scaling, reducing them to a pattern of interstimulus similarities. In addition, color‐naming data were collected for five of the languages and confirmed that sorting responses were not simply a reflection of the words used by subjects to label the stimuli. A “clustering index” was created, quantifying the extent of light/dark blue separation and the strength of any category boundary between them; this was low for English‐language participants but high for Russian and Italian. Udmurt and Lithuanian values were also high, whereas Estonian responses were closer to English. Thus, when clustering of blue stimuli is used as an additional indicator of basicness, the results are compatible with earlier evidence that “light blue” is a separate basic color category in Russian and Italian, and further indicate that light blue terms are basic in Udmurt and Lithuanian, but not Estonian. It may be that “blue” categories are especially susceptible to splitting into two under the influence of linguistic contact. © 2016 Wiley Periodicals, Inc. Col Res Appl, 42, 362–377, 2017     

Hg(II) removal with polyacrylamide grafted crosslinked poly(vinyl chloride) beads via surface‐initiated controlled/“living” radical polymerization

Polyacrylamide grafted crosslinked poly (vinyl chloride) beads (PAM‐PVC) were prepared by the surface‐initiated controlled/“living” radical polymerization (SI‐CLRP) methodology from the crosslinked poly(vinyl chloride) beads with surface modification with diethyldithiocarbamyl groups under UV irradiation. The macroiniferter, diethyldithiocarbamyl crosslinked poly(vinyl chloride) beads (DEDTC‐PVC) were prepared by the reaction of the surface C? Cl groups with sodium N,N‐diethyl dithiocarbamate. The “grafting from” polymerization exhibited some “living” polymerization characteristics and the percentage of grafting (PG%) increased linearly with polymerizing time and achieved 47.6% after 6 h UV irradiation. The beaded polymer with polyacrylamide surface was also characterized with Fourier transform infrared (FTIR) and scanning electron microscope (SEM). Its adsorption property for Hg(II) ion was also investigated preliminarily. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:3385–3390, 2006     

“Click” Polymer‐Supported Palladium Nanoparticles as Highly Efficient Catalysts for Olefin Hydrogenation and Suzuki Coupling Reactions under Ambient Conditions

Complexation of palladium(II) acetate [Pd(OAc)₂] or dipotassium tetrachloropalladate [K₂PdCl₄] to “click” polymers functionalized with phenyl, ferrocenyl and sodium sulfonate groups gave polymeric palladium(II)‐triazolyl complexes that were reduced to “click” polymer‐stabilized palladium nanoparticles (PdNPs). Transmission electron microscopy (TEM) showed that reduction using sodium borohydride (NaBH₄) produced PdNPs in the 1–3 nm range of diameters depending on the nature of the functional group, whereas slow reduction using methanol yielded PdNPs in the 22–25 nm range. The most active of these PdNPs (0.01% mol Pd), stabilized by poly(ferrocenyltriazolylmethyl)styrene, catalyzed the hydrogenation of styrene at 25 °C and 1 atm hydrogen, with turnover numbers (TONs) of 200,000. When stabilized by the water‐soluble poly(sodium sulfonate‐triazolylmethyl)styrene, the PdNPs (0.01% mol Pd) catalyze the Suzuki–Miyaura coupling between iodobenzene (PhI) and phenylboronic acid [PhB(OH)₂] in water/ethanol (H₂O/EtOH) at 25 °C with TONs of 8,200. This high catalytic activity is comparable to that obtained with “click” dendrimer‐stabilized PdNPs under ambient conditions.