National Information and Documentation Centre (NIDOC), Academy of Scientific Research and Technology, ASRTEgyptian Journal of Chemistry0449-228556420130830New Starch Hybrids via Etherification of Poly (Acrylamide)-Starch Copolymers with Acrylamide255270111210.21608/ejchem.2013.1112ENJournal Article20130917
<span style="font-size: xx-small;">NOVEL starch hybrids containing acrylamide (Aam) moieties in …….monomeric (</span><em><span style="font-family: Times New Roman,Times New Roman; font-size: xx-small;"><span style="font-family: Times New Roman,Times New Roman; font-size: xx-small;">i.e </span></span></em><span style="font-size: xx-small;">carbamoylethyl groups) and polymeric (poly acrylamide) forms were synthesized. Thus, starch was first polymerized with acrylamide to yield poly (Am)-starch composite and poly (Aam)-starch graft copolymer which represent the total polymerization products before and after removal of the homopolymer, respectively. The composite and the copolymer were then carbamoyethylated via reaction with Aam. Beside the carbamoylethyl groups, carboxyethyl groups were inevitably formed during carbamoylethylation. This and the onset of such modification on the rhelogical properties of the so synthesized starch hybrids signify the following. a) The extents of carbamoylethylation of the composite and the copolymer were much lower than native starch; b) The magnitude of poly(Am) content in the form of graft or homopolymer adversely affects the carbamoylethylation reaction; c) before carbamoylethylation, the composite, the copolymer and native starch exhibited non-Newtonian thixotropic behavior, d); after carbamoylethylation the etherified products were characterized by pseudoplastic behavior. The apparent viscosity of starch, starch composite and starch copolymer decreased significantly after carbamoylethylation but with the certainty that the apparent viscosity increased by increasing the carbamoylethyl and carboxyethyl groups in these starch hybrids. </span>https://ejchem.journals.ekb.eg/article_1112_6417c20ec915254f137174eb75eb78d0.pdfNational Information and Documentation Centre (NIDOC), Academy of Scientific Research and Technology, ASRTEgyptian Journal of Chemistry0449-228556420130830Modulation of the Nanostructural Characteristics of Cellulose Nanowhiskers via Sulfuric Acid Concentration271289111310.21608/ejchem.2013.1113ENJournal Article20130917CELLULOSE nanowhiskers (CNW) were synthesized from native cotton cellulose as per the acid hydrolysis methods. Thus Egyptian cotton slivers, after being purified, were subjected to three sulfuric acid concentrations, viz. 55%, 60% and 65% (w/w) at 60
<span style="font-family: Times New Roman; font-size: xx-small;"><span style="font-family: Times New Roman; font-size: xx-small;">0</span></span><span style="font-family: Times New Roman; font-size: xx-small;"><span style="font-family: Times New Roman; font-size: xx-small;">C for 60 min. The yield of CNW attains values of 65%, 57% and 50%, respectively. The amorphous regions along with thinner as well as shorter crystallites spreaded throughout the cellulose structure are digested by the acid leaving CNW suspension. The latter could be freeze-dried and CNW powder could be achieved. A thorough investigation pertaining to nanostructural characteristics of CNW was performed. These characteristics could be monitored using TEM for morphology, sizes and size distribution, XRD for degree of crystallinity and crystalline structure, FTIR spectra for following the changes in functionality and TGA for studying the sample weight loss as a function of temperature. Based on the results obtained CNW prepared using 60% w/w sulfuric acid are nominated as the best candidate within the range studied in the area of reinforcement by virtue of their salient features.</span></span>https://ejchem.journals.ekb.eg/article_1113_aa6251153029722f8653d0414e06d1a3.pdfNational Information and Documentation Centre (NIDOC), Academy of Scientific Research and Technology, ASRTEgyptian Journal of Chemistry0449-228556420130830Efficient Synthesis of Biopertinent Dihydropyrimidine (thi) one Derivatives via Three-component One-pot Synthesis Catalyzed by Tetrachlorosilane291305111410.21608/ejchem.2013.1114ENJournal Article20131106
<span style="font-size: xx-small;">SERIES of dihydropyrimidine(thi)one derivatives were prepared, in …..good yields at room temperature by using a modified Biginelli reaction. The products were obtained through a one-pot three-component coupling of β-diketones, aldehydes and urea (or thiourea) in the presence of a catalytic amount of tetrachlorosilane (TCS). The effect of catalyst type, molar ratios of reactants and solvent type were also investigated; best results were obtained when TCS was employed as a catalyst and CH</span><span style="font-size: xx-small;">2</span><span style="font-size: xx-small;">Cl</span><span style="font-size: xx-small;">2 </span><span style="font-size: xx-small;">as a solvent at room temperature. </span>https://ejchem.journals.ekb.eg/article_1114_8590f1471e4f88d58a7751c6fdf4b832.pdfNational Information and Documentation Centre (NIDOC), Academy of Scientific Research and Technology, ASRTEgyptian Journal of Chemistry0449-228556420130830Synthesis, Characterization and Thermal Behavior of Novel Acrylate Polymers Based on N-(benzothiazole-2-yl) Maleimide307323111510.21608/ejchem.2013.1115ENJournal Article20131107
<span style="font-size: xx-small;">IN the present study novel acrylate polymers were prepared from … different feed compositions of ethyl acrylate (EA), methyl methacrylate (MMA), styrene (St) and N-(benzothiazole-2-yl) maleimide (BTM) monomer via emulsion polymerization technique using sodium lauryl sulfate as a surfactant and ammonium persulfate as an initiator. The chemical structure of BTM monomer was confirmed by elemental analysis in addition to FT-IR, </span><span style="font-size: xx-small;">1</span><span style="font-size: xx-small;">H-NMR and mass spectroscopy. The prepared acrylate polymers of different compositions were also investigated by FT-IR, GPC, TGA and DSC. The solubility of both BTM monomer and the formed polymers of different compositions in various solvents was also investigated. The obtained results showed that the thermal decomposition of the prepared polymers which has taken place occurred in a single step in the temperature range from 345 to 436°C. The mechanism of the thermal degradation of the prepared polymers was confirmed via kinetic analysis of their thermal degradation using Broido, Coats-Redfern and Horowitz-Metzger methods. </span>
<span style="font-size: xx-small;"> </span>https://ejchem.journals.ekb.eg/article_1115_4f4986b16713f63223369363531b88be.pdfNational Information and Documentation Centre (NIDOC), Academy of Scientific Research and Technology, ASRTEgyptian Journal of Chemistry0449-228556420130830Origin and Distribution of Polycyclic Aromatic Hydrocarbons (PAHs) in Surface Water of Suez Gulf325344111610.21608/ejchem.2013.1116ENJournal Article20131001
<span style="font-size: xx-small;">THE SUEZ Canal is the passage to the international trade between ……east and west, thus several waste pollutants are easily disposed and dumped into the boundaries of the studied area. The pollutants vary from raw sewage, oil spills, and industrial effluents to garbage which has tremendous impacts on the marine environment. Most of these sources in the investigated area mainly occurred from the human activities, </span><em><span style="font-family: Times New Roman,Times New Roman; font-size: xx-small;"><span style="font-family: Times New Roman,Times New Roman; font-size: xx-small;">e.g. </span></span></em><span style="font-size: xx-small;">Industrial wastes, domestic draining of the Suez City and ship's oil. Distribution and origin of polycyclic aromatic hydrocarbons of (PAHs) in the collected water samples revealed the origin of (PAHs) is petrogenic and pyrogenic or mixture of (petrogenic and pyrogenic). Levels of PAHs varied between (1.640, 39.139) μg/L and (0.7317, 21.9373) μg/L for summer and winter, respectively. These results indicate high level of contamination. It is recommended that more effort and rules should be carried out in order to govern, prevent or even minimize the sources of pollutants. </span>https://ejchem.journals.ekb.eg/article_1116_7fa4156927d443908b75dc0c3b7745bb.pdf