Evaluation of polypropylene/clay nanocomposite foamability based on their morphological and rheological aspects

2018 ◽  
Vol 54 (5) ◽  
pp. 829-850 ◽  
Author(s):  
Anindya Dutta ◽  
Sabapathy Sankarpandi ◽  
Anup K Ghosh

To identify the effect of rheological influence on the development of microstructure in polypropylene/clay nanocomposites and thereby the influence of the developed microstructure on the foamability of the nanocomposites, a set of nanocomposites was prepared and batch foamed using supercritical CO2. Polypropylene and nanoclay were selected for preparing nanocomposites. During foaming, the nanocomposites were saturated with CO2 gas for three different time periods and subsequently in-situ heating was done to achieve cell growth. The gas saturation was done at subcritical condition followed by the foaming at critical condition of CO2. Thermal studies of the composites were investigated through differential scanning calorimetry, and clay dispersion morphology was investigated and validated using wide-angle X-ray diffraction, transmission electron microscopy, and parallel plate rheology. The improvement in foam morphology (cell size and cell density) and subsequent reduction in foam density was analyzed. The fingerprint characteristics of nanocomposites have an enormous role on foam structure development. With the increase in clay loading, cell density increased; furthermore, with an increase in saturation time, there was a phenomenal decrease in expansion ratio of neat polypropylene due to CO2-induced crystallization which could be mitigated by the incorporation of nanoclay into the polypropylene matrix. Therefore, nanoclay could be exploited as the inhibitor of CO2-induced crystallization.

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Limei Wang ◽  
Aihua He

Polypropylene (PP)/clay nanocomposites were synthesized by in situ intercalative polymerization with TiCl4/MgCl2/clay compound catalyst. Microstructure and thermal properties of PP/clay nanocomposites were studied in detail. Fourier transform infrared (FTIR) spectra indicated that PP/clay nanocomposites were successfully prepared. Both wide-angle X-ray diffraction (XRD) and transmission electron microscopy (TEM) examination proved that clay layers are homogeneously distributed in PP matrix. XRD patterns also showed that theαphase was the dominate crystal phase of PP in the nanocomposites. Thermogravimetric analysis (TGA) examinations confirmed that thermal stability of PP/clay nanocomposites was markedly superior to pure PP. Differential scanning calorimetry (DSC) scans showed that the melt temperature and the crystallinity of nanocomposites were slightly lower than those of pure PP due to crystals imperfections.


Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1397 ◽  
Author(s):  
Elaine dos Santos ◽  
Marcus Fook ◽  
Oscar Malta ◽  
Suédina de Lima Silva ◽  
Itamara Leite

Purified clay was modified with different amounts of alkyl ammonium and phosphonium salts and used as filler in the preparation of PET nanocomposites via melt intercalation. The effect of this type of filler on morphology and thermal and mechanical properties of PET nanocomposites was investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analyses (TG), tensile properties, and transmission electron microscopy (TEM). The results showed that the mixture of alkyl ammonium and phosphonium salts favored the production of PET nanocomposites with intercalated and partially exfoliated morphologies with slight improvement in thermal stability. In addition, the incorporation of these organoclays tended to inhibit PET crystallization behavior, which is profitable in the production of transparent bottles.


2018 ◽  
Vol 32 (8) ◽  
pp. 1078-1091 ◽  
Author(s):  
Sibel Erol Dağ ◽  
Pınar Acar Bozkurt ◽  
Fatma Eroğlu ◽  
Meltem Çelik

A series of polystyrene (PS)/unmodified Na-montmorillonite (Na-MMT) composites were prepared via in situ radical polymerization. The prepared composites were characterized using various techniques. The presence of various functional groups in the unmodified Na-MMT and PS/unmodified Na-MMT composite was confirmed by Fourier transform infrared spectroscopy. Morphology and particle size of prepared composites was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). According to the XRD and TEM results, the interlayer spacing of MMT layers was expanded. SEM images showed a spongy and porous-shaped morphology of composites. TEM revealed the Na-MMT intercalated in PS matrix. The thermal stability of PS/unmodified Na-MMT composites was significantly improved as compared to PS, which is confirmed using thermogravimetric analysis (TGA). The TGA curves indicated that the decomposition temperature of composites is higher at 24–51°C depending on the composition of the mixture than that of pure PS. The differential scanning calorimetry (DSC) results showed that the glass transition temperature of composites was higher as compared to PS. The moisture retention, water uptake, Brunauer–Emmett–Teller specific surface area, and specific pore volume of composites were also investigated. Water resistance of the composites can be greatly improved.


2007 ◽  
Vol 124-126 ◽  
pp. 1083-1086
Author(s):  
Jun Hee Sung ◽  
Hyoung Jin Choi

Nanocomposites of conducting polymers of polyaniline (PANI), poly(oethoxyaniline) (PEOA) and polypyrrole (PPy) with clay prepared via either in-situ emulsion polymerization or solvent intercalation were investigated especially for electrorheological fluid (ER) application. Internal structures of these nanocomposites were examined via wide angle X-ray diffraction (WAXD), and transmission electron microscope (TEM). The intercalated nanostructures analyzed via WAXD and TEM were correlated with the electrical property change originated from the nanoscale interaction between clay and conducting polymer. Moreover, their ER behaviors were measured via rotational rheometer with external electric field controller.


e-Polymers ◽  
2013 ◽  
Vol 13 (1) ◽  
Author(s):  
Mohammad Galehassadi ◽  
Fatemeh Hosseinzadeh ◽  
Mehrdad Mahkam

Abstract Nanocomposites of polystyrene (PS) was prepared with new styrenic ionic liquid, N-(4-vinyl benzyl)-(N,N-dimethylamino) pyridinium chloride[VBMAP], surfactants used as organic modifications for the clays. Sodium montmorillonite (Na-MMT) was successfully modified by [VBMAP] to become OMMT through cation exchange technique which is shown by the increase of basalspacing of clay by XRD. The composite material based on polystyrene and organo-modified montmorillonite (OMMT) was prepared by insitu polymerization and characterized. The morphology of the polymer/clay hybrids was evaluated by X-ray diffraction (XRD) ,transmission electron microscopy (TEM) and scanning electron microscopy (SEM), showing good overall dispersion of the clay. The thermal stability of the polymer/clay nanocomposites were enhanced, as evaluated by thermogravimetric analysis.


2009 ◽  
Vol 2009 ◽  
pp. 1-5 ◽  
Author(s):  
E. M. Araújo ◽  
K. D. Araujo ◽  
R. A. Paz ◽  
T. R. Gouveia ◽  
R. Barbosa ◽  
...  

Polyamide 66 (PA66)/Brazilian clay nanocomposites were produced via direct melt intercalation. A montmorillonite sample from the Brazilian state of Paraíba was organically modified with esthearildimethylammonium chloride (Praepagen), quaternary ammonium salt and has been tested to be used in polymer nanocomposites. The dispersion analysis and the interlayer spacing of the clay particles in matrix were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Thermal behavior of the obtained systems was investigated by differential scanning calorimetry (DSC), thermogravimetry (TG), and heat deflection temperature (HDT) was reported too. The nanocomposites exhibited a partially exfoliated structure, very interesting HDT values which are higher than those of pure PA66, and good thermal stability.


Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1983 ◽  
Author(s):  
Rui Jiang ◽  
Tao Liu ◽  
Zhimei Xu ◽  
Chul B. Park ◽  
Ling Zhao

In-situ fibrillated polytetrafluoroethylene (PTFE) enhanced nanocomposites were successfully prepared by mixing thermoplastic polyether ester elastomer (TPEE) and PTFE using a twin-screw extruder. Well-dispersed, long aspect ratio PTFE nanofibrils with a diameter of less than 200 nm were generated and interwoven into networks. Differential scanning calorimetry and in-situ polarized optical microscopy showed that the PTFE nanofibrils can greatly accelerate and promote crystallization of the TPEE matrix and the crystallization temperature can be increased by 6 °C. Both shearing and elongational rheometry results confirmed that the introduction of PTFE nanofibrils can significantly improve the rheological properties. The remarkable changes in the strain-hardening effect and the melt viscoelastic response, as well as the promoted crystallization, led to substantially improved foaming behavior in the continuous extrusion process using supercritical CO2 as the blowing agent. The existing PTFE nanofibrils dramatically decreased the cell diameter and increased cell density, together with a higher expansion ratio and more uniform cell structure. The sample with 5% PTFE fibrils showed the best foaming ability, with an average diameter of 10.4–14.7 μm, an expansion ratio of 9.5–12.3 and a cell density of 6.6 × 107–8.6 × 107 cells/cm3.


2006 ◽  
Vol 317-318 ◽  
pp. 669-672 ◽  
Author(s):  
D.H. Kim ◽  
Seong Soo Park ◽  
B.S. Jun ◽  
Jong Kook Lee ◽  
Kyu Hong Hwang ◽  
...  

Polymer/layered silicate nanocomposities were prepared by in situ polymerization with microwave process. The influence of the amount of clay on the structure and thermal properties for the synthesized nanocomposites were characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). It was found that the structure of nanocomposites, an intercalated/exfoliated structure, depended on the clay content.


2008 ◽  
Vol 23 (4) ◽  
pp. 941-948 ◽  
Author(s):  
Z.W. Zhu ◽  
S.J. Zheng ◽  
H.F. Zhang ◽  
B.Z. Ding ◽  
Z.Q. Hu ◽  
...  

Different bulk metallic glasses (BMGs) were prepared in ductile Cu47.5Zr47.5Al5, Zr62Cu15.4Ni12.6Al10, and brittle Zr55Ni5Al10Cu30 alloys by controlling solidification conditions. The achieved microstructures were characterized by x-ray diffraction, differential scanning calorimetry, transmission electron microscopy, and synchrotron- based high-energy x-ray diffraction. Monolithic BMGs obtained by high-temperature injection casting are brittle, while BMGs bearing some nanocrystals with the size of 3 to 7 nm and 2 to 4 nm, obtained by low-temperature injection casting and in situ suction casting, respectively, exhibit good plasticity. It indicates that the microstructures of BMGs are closely affected by the solidification conditions. Controlling the solidification conditions could improve the plasticity of BMGs.


e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Fan Xufen ◽  
Chen Dajun

AbstractPoly (ethylene terephthalate) (PET)/Attapulgite (AT) nanocomposites were prepared via in-situ polymerization. According to the observation of transmission electron microscopy (TEM), attapulgite is well dispersed in the PET matrix in a nanometer scale. The influence of attapulgite content on the nonisothermal crystallization kinetics was studied using a classical Avrami equation with Jeziorny method. The crystalline structures of the pure PET and PET/AT nanocomposites with different amount of AT (0.2%, 0.5%, 1%, 2%) were characterized by differential scanning calorimetry (DSC) and X-ray diffraction (XRD) methods. It was found that the crystallization temperature for PET/AT nanocomposites with 0.2% and 0.5% content of AT were higher than pure PET and the rate of crystallization of all PET/AT nanocomposite samples increased significantly which indicated that attapulgite could be used as an effective nucleating agent in PET. However, with the addition of AT, smaller crystalline size, more crystalline defects and lower degree of crystallization was demonstrated.


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