توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱distance sampling : line transect
نویسنده(ها):
اطلاعات انتشار: ششمین کنفرانس آمار ایران، سال
تعداد صفحات: ۱۱
distance sampling is a widely –used group of closely related methods for estimating the density and or abundance of biological populations.<\div>

۲Effect of nanoclay surface modifier chemical reactivity on the morphology and the rheological properties of the PP\PA6 blend nanocomposite
نویسنده(ها): ، ،
اطلاعات انتشار: کنفرانس بین المللی فرآورش پلیمرها، سال
تعداد صفحات: ۱۰
An attempt was made to explore the role of nanoclay surface modifier chemical reactivity on the morphology and the rheological properties of a polypropylene\polyamide6 (PP\PA6 75\25) nanocomposite blend. The Na–MMT surface was modified with two types of cations; a) diamine cation (D–Clay), and b) a combination of diamine and quaternary alkylammonium cations (A–Clay) via cation exchange reaction. The nanocomposites samples compatibilized with PP–g–MA were prepared by melt compounding in an internal mixer. The XRD patterns indicated the intercalated\exfoliated microstructure for both nanocomposite samples. The SEM results showed a significantly decreases in the PA6 droplet size, from 3.2 μm of the simple blend to the 0.4 μm in the D–Clay containing sample. Moreover, in the sample containing A–Clay the average droplet size was found to be 1 μm. The D–Clay containing sample showed the rheological properties similar to simple blend in high frequencies with a nonterminal behavior in low frequencies storage modulus. This was explained by locating of D–Clay layers in the interphase and hence, significantly reducing the effective interfacial tension, α\R. In contrast, the sample containing A–Clay showed an increased complex viscosity and storage modulus in whole range of frequencies, which was attributed to presence of a great amount of A–Clay layers in the PP matrix. These types of nanoclay partitioning were explained by possibility of chemical reaction between amine group of nanoclay surface modifier and maleic group of PP–g–MA compatibilizer or in–situ formed block copolymer. Consequently, the D–Clay layers bounded with PP–g–MA is preferentially located in the interphase, while, the non reactive nanoclay layers (containing alkylammonium cations) is dispersed in the PP matrix by assistance of PP–g–MA. These findings were also evidenced by TEM micrograph of both nanocomposite samples<\div>

۳STUDY ON MICROSTRUCTURE DEVELOPMENT OF PS\ORGANOCLAY PREPARED BY IN SITU SOLUTION POLYMERIZATION PROCESS
نویسنده(ها): ، ،
اطلاعات انتشار: اولین همایش ملی تکنولوژی های نوین در شیمی و پتروشیمی، سال
تعداد صفحات: ۶
The main objective of the present work was to synthesis polystyrene–clay nanocomposites through solution polymerization of styrene monomer in the presence of organomodifiedmontmorillonite (OMMT) clay. Polymerization was carried out in a 500cc laboratory batch reactor (3–neck). The results of the thermal analysis, including Thermo Gravimetric Analysis (TGA)and Differential Scanning Calorimeter (DSC), showed a greater thermal stability for thenanocomposites samples compare to neat polystyrene. The FTIR characteristic picks of the nanocomposites samples were found to be similar to those observed for polystyrene. XRD patternsshowed relatively high extent of intercalation which remained almost unchanged after completing ofthe reaction (after 6 hours). The results of linear viscoelastic measurements performed on the samples showed a higher viscosity and storage modulus (G') particularly at low shear rate range compared to neat polystyrene by the same polymerization condition. The melt linear viscoelastic results also showedthat increasing the reaction time after 6 hours does not have effect on the dispersion of nanoclay inpolystyrene matrix. In addition, after that due to some side reactions such as transfer reaction to solvent, occurring in the reactor, and the molecular weight of samples decrease with increasing the reaction period after 6 hours<\div>

۴THE EFFECT OF FEEDING ORDER ON MICROSTRUCTURE AND RHEOLOGICAL PROPERTIES OF POLY(BUTYLENE TEREPHTALATE)\EPOXY\CLAY HYBRID SYSTEMS
نویسنده(ها): ، ،
اطلاعات انتشار: اولین همایش ملی تکنولوژی های نوین در شیمی و پتروشیمی، سال
تعداد صفحات: ۵
The main objective of the present work was investigation the effect of feeding order or blending sequence on the microstructure and rheological properties of PBT\epoxy\clay ternarynanocomposites. The hybrid nanocomposite was prepared in a laboratory internal mixer (Brabender).Three different mixing sequences were used: 1) mixing PBT, epoxy and Cloisite 30B in one step; 2)first mixing of PBT and Cloisite 30B then mix them with epoxy; and 3) prepare epoxy\Cloisite 30Bhybrid first, then mix it with PBT to get the final nanocomposites. The good dispersion of clay in thehybrid nanocomposites was confirmed by X–ray diffraction, transmission electron microscopy and rheological measurement. The results from X–ray diffraction reveal that in all prepared samples presentan intercalated structure. However, feeding order has no appreciable effect on the interlayer spacing ofnanoclay. But from the rheological results it was demonstrated that feeding order has a significant role on the distribution or partitioning of nanoclays in two phases. In sample prepared via blendingsequence (2) the nanoclay was well dispersed and distributed in the nanocomposites, whereas in thesample from blending sequence (3) the nanoclay was trapped in epoxy droplet and due to high affinity between epoxy and nanoclay, it could not migrate to PBT matrix.<\div>
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