توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱A Study of Coating Adhesion on an Oxidized Wax Containing Polypropylene
نویسنده(ها): ، ،
اطلاعات انتشار: سومین کنگره بین المللی رنگ و پوشش، سال
تعداد صفحات: ۷
Polypropylene has experienced wide commercial surface pretreatment techniques to attain good coating adhesion. In this study, the influence of polar surface modifier; Oxidized Polypropylene Wax (OPPW) was investigated mainly on the surface properties of its blends with polypropylene. Pull off adhesion test was employed to evaluate the adhesion strength of an acrylic based coating. The incorporation of polar wax caused almost linear increase in both surface energy and coating adhesion of the blends. A maximum surface energy of about 37 mJ\m2 was obtained for the compound containing 10 wt% OPPW. The adhesion promotion approach is believed to work via good molecular contact, specific interfacial interactions between polar components of both coating layer and the outermost OPPW chains at the surface. Prior to coating application, a heat treatment stage (60 ºC for 100 hours) on substrates increased the coating adhesion substantially. ATR spectroscopy was useful technique in characterizing polar groups in the surface region of blends<\div>

۲Synthesis, characterization and formation mechanism of nanosized β–tricalcium phosphate with plate–like structure
نویسنده(ها): ، ، ،
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۹
A simple route for synthesizing nano–sized β–tricalcium phosphate (β–TCP) powder is using chemical precipitation method through aqueous solution of diammonium hydrogen phosphate (NH4)2HPO4 and calcium nitrate Ca(NO3)2 as the row materials. In this paper, nano–sized β– TCP was prepared with low concentration of precursors and low addition rate of the second phase to first phase. The crystal β–TCP powders were obtained after the precursors had beenmixed for 24 h, then dried at 80–100 °C and calcined at 800 °C. The morphology and phase composition were analyzed by SEM, AFM, XRD and EDXA. The product largely consisted of porous plated crystals of 50–100 nm in thickness, holes whenpresent were 100–300 nm in diameter. The Ca\P ratio of the resulting powders was strongly dependent on the pH of the solution, concentration and addition rate of row materials<\div>

۳Purification of Carboxymethyl Chitosan and Investigation of its properties
نویسنده(ها): ، ، ،
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۱۲
Biopolymers from marine sources have been studied and used in commercial applications and product development for a number of years. Chitosan, a linear polysaccharide consisting of glucosamine and N–acetyl glucosamine derived mainly from crustacean shells, has been used in many technicalapplications such as water purification (as a flocculant), in cosmetics, and recently as a proposed fatbinding weight control product because of its nontoxicity, biocompatibility and biodegradability. In solution, the cationic nature of chitosan gives this polymer a mucoadhesive property. Chitosan salts, likecarboxymethyl chitosan (CMCS) as a smi–synthetic biopolymer, can be used as a matrix or scaffold material as well as in nonparenteral delivery systems for challenging drugs. CMCS has been shown to increase the transport of polar drugs across the nasal epithelial surface. The purpose of this work is toidentify key parameters relevant for the characterization of CMCS for the development of new commercial applications of that for the biomedical and pharmaceutical industries<\div>

۴Preparation of Carboxymethyl Chitosan Nanospheres via its Crosslinking of in an Inverse Microemulsion System as Carrier for Amphotericin B Delivery
نویسنده(ها): ، ، ،
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۱۲
Natural biopolymers or their semi–synthetic derivatives are widely interested for drug or gene delivery applications. Carboxymethyl chitosan (CMCS) as a smi–synthetic biopolymer is nontoxic, biocompatible, biodegradable and mucoadhesive; it has well–known macrophage activation property which renders ithighly useful for drug delivery to macrophages. Here, fabrication of biodegradable CMCS nanospheres will be reported using an inverse microemulsion technique to provide particles of controlable size; and its distribution and morphology. Microemulsions were prepared by dispersion of CMCS aqueous acidicsolutions (using acetic acid) in n–hexane continuous phase. AOT and glutaraldehyde were used as an emulsifier and a crosslinking agent, respectively. Virgin CMCS and the resulting nanospheres were throughly characaterized using spectroscopic (FTIR spectroscopy) and micropscopic (SEM) methods to study the cross–linking reaction mechanism and particle size and morphology, respectively. The obtainedparticle perfectly spherical in the range of 100–300 nm diameter with a narrow size distribution according to the SEMs. Crosslinking of CMCS was confirmed in FTIR spectra by appearance of signal bands at 2889 cm–1 which represent the stretching vibration of C=N bond. During a series of experiments theconcentration of the CMCS, the concentration of the AOT and the concentration of the glutaraldehydewere varied according to a plan obtained by four factorial three levels experimental design. The depending variable was the mean size of the CMCS nanospheres. After evaluating the result of theexperiments it was found that the concentration of AOT had significant influence on the particle size,while surprisingly the concentration of the glutaraldehyde had only non significant, minor effect. The obtained nanospheres were used for Amphotericin B delivery.<\div>
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