• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.291-291
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• 2006

Two different sources of clay, Na-Bentonite (Thai local clay) and Na-Montmorillonite were modified with Hexadodeccyltrimethyl ammonium bromide. The nanocomposites of polypropylene were successfully prepared via melt blending in a co-rotating twin screw extruder by using PP-g-MA as a compatibilizer at various contents of organoclays. The morphology of nanocomposites was investigated by using XRD and SEM. The results showed that the intercalated and exfoliated structures were obtained. The thermal behavior was also studied by using DSC and TGA. The degradation temperature of filled PP was greater than that of unfilled PP by 20%. And, the tensile strength and modulus were improved when a small amount of organoclays were added.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.280-280
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• 2006

Na-bentonite (local clay mineral) and Na-montmorillonite were treated with quaternary alkylammonium cations. The effect of the molecular structure and functional groups of the surfactants on the organoclays was investigated by X-ray diffraction (XRD). For the preparation of nanocomposites, organoclays were melt-blended with polypropylene in a twin screw extruder and $Surlyn^{(R)$. ionomer was used as a reactive compatibilizer. The clay dispersions in the composites were investigated by X-ray diffraction (XRD). XRD spectra showed no peak at low angle indicated that the silicate clay layer has a nearly exfoliated dispersion in the polymer matrix. Thermal and mechanical properties of nanocomposites were higher than those of PP.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.367-367
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• 2006

With poly (ethylene-co-methacrylic acid) ionomer (i.e. Surlyn) as a compatibilizer, PP/organoclay (Cloisite(R)20A) nanocomposites were prepared via melt compounding in a co-rotating twin-screw extruder. For comparison, the widely used PP-g-MA was also used as a reference. The content of organoclay was fixed at 5phr based on the total weight of polymer resins. The structures of nanocomposites were characterized by XRD, rheometry in small amplitude oscillatory shear, SEM, and TEM, respectively. It was found that PP/Surlyn/OMMT nanocomposites displayed higher intercalation degree and better dispersion effect than the corresponding PP/PP-g-MA/OMMT counterpart. Additionally, their mechanical properties and wettability were measured.

• Carbon letters
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• v.11 no.2
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• pp.83-89
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• 2010

We prepared polycarbonate (PC)/poly(methyl methacrylate) (PMMA)/multiwall carbon nanotube (MWCNT) nanocomposites by co-rotating twin screw extruder at 533 K. Thermal analysis results indicate that the miscibility of PC and PMMA is enhanced by MWCNTs. Bead necklace-like morphology of PMMA-rich phase is observed in PC/PMMA/MWCNT nanocomposites with increasing PMMA weight fraction due to the bead necklace-like morphology. The tensile strength of PC/PMMA (75/25)/MWCNT (1 wt.%) nanocomposite is 3% higher than those of PC/PMMA (75/25) alloy. Suppression of die swell by MWCNT filler is observed in the melt flow of PC/PMMA/MWCNT nanocomposites during extrusion.

• Composites Research
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• v.31 no.5
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• pp.202-208
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• 2018

In this paper, mechanical and hygroscopic properties of teak sawdust and recycled polypropylene (RPP) composites are evaluated and compared with virgin polypropylene (VPP) matrix based composites. Verities of composites are prepared by variation in the plastic types, wood plastic ratio and the addition of coupling agent in the formulations. Mixing of wood sawdust and polypropylene is done by a twin screw extruder, and then sheets of wood plastic composites (WPCs) are produced by using the compression molding method. The results show that recycled matrix composites exhibit better tensile, flexural strength with low impact strength than virgin matrix based composites. Recycled composites show low water absorption and thickness of swelling than virgin matrix based composites. The results confirm that wood content in the polymer matrix affects the performance of composites while presence maleated polypropylene (MAPP) improves the properties of the composites significantly. Developed RPP matrix composites are as useful as VPP matrix composites and have the potential to replace the wood and plastics products without any adverse effect of the plastics on the environment.

• Korea-Australia Rheology Journal
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• v.16 no.4
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• pp.213-218
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• 2004

Linear high-density polyethylene (PE) was controlled to induce strain-hardening behavior by introducing a small amount of second component with an anisotropic structure. In order to form an anisotropic structure in the PE matrix, the polymer was extruded through a twin-screw extruder, and the structure was controlled by varying the extrusion conditions. Depending on conditions, the second component formed a film, thread and droplet structure. If the second component was kept rigid, the morphology evolution could be delayed and the second component could maintain its film or thread structure without further relaxation. In par­ticular, the second component of the thread structure made a physical network and gave rise to remarkable strain hardening behavior under high extension. This study suggests a new method that induces strain hard­ening behavior by introducing a physically networked second component into the linear polymer melt. This result is anticipated to improve the processibility of linear polymers especially when extensional flow is dominant, and to contribute to our understanding of strain hardening behavior.

• Macromolecular Research
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• v.8 no.3
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• pp.120-124
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• 2000

Clay-dispersed nanocomposites have been prepared by simple melt-mixing of two components, styrenic polymers with different content of functional groups and two different organophilic clays (Cloisite(R) 25A and Cloisite(R)30A) with a twin screw extruder. Dispersibility of 10-$\AA$-thick silicate layers of clay in the hybrid was investigated by using an X-ray diffraction method and a transmission electron microscope. It was found that if the interaction force between intercalant and matrix polymer is attractive, the matrix polymer intercalates more rapidly into the gallery of silicate layers. The faster intercalation of matrix polymer leads to the better dispersibility of silicate layers in the matrix polymer.

• International Journal of Precision Engineering and Manufacturing
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• v.9 no.4
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• pp.71-73
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• 2008

The development of polymer/inorganic nanocomposites has attracted a great deal of interest due to the improved hybrid properties derived from the two different components. Various nanoscale fillers have been used to enhance polymer mechanical and thermal properties, such as toughness, stiffness, and heat resistance. The effects of the filler on the final properties of the nanocomposites are highly dependent on the filler shape, particle size, aggregate size, surface characteristics, polymer/inorganic interactions, and degree of dispersion. In this paper, we describe the influence of different $CaCO_3$ dispersion methods on the thermal properties of polyethylene terephthalate (PET)/$CaCO_3$ composites: i.e., the adsorption of $CaCO_3$ on the modified PET surface, and the hydrophobic modification of the hydrophilic $CaCO_3$ surface. We prepared PET/$CaCO_3$ nanocomposites using a twin-screw extruder, and investigated their thermal properties and morphology.

• Elastomers and Composites
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• v.51 no.4
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• pp.350-354
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• 2016

The surface properties of poly(methyl methacrylate) (PMMA) were investigated after accelerated weathering. Glossinesses, contact angles, surface free energies, thermal stability, and mechanical properties were investigated. The glossiness of the weathered PMMA was decreased with increasing exposure time. Contact angles and surface free energies were not overtly changed because the amount of oxygen on the surface was remained. PMMA was compounded with anti-block and antistatic agents using a co-rotating twin screw extruder to improve the durability. The PMMA composites showed better glossinesses after accelerated weathering while maintaining the contact angles, surface energy, thermal stability, and mechanical properties without significant changes.

• Elastomers and Composites
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• v.55 no.1
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• pp.1-5
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• 2020

This study examined the effects of the addition of maleic anhydride-grafted polypropylene (PP-g-MA) and polyolefin elastomer (POE) on polyamide 66 (PA66) and polypropylene (PP) blends. The blends of PA66/PP with PP-g-MA and POE were prepared using a twin screw extruder. Mechanical testing results revealed that the tensile, flexural, and izod impact strengths of the blends were maximized at a PP-g-MA content of 2 phr. The increased mechanical strength of the blends with PP-g-MA was attributed to the compatibilizing effect of the PA66 and PP blends. In addition, as the POE content increased, the impact strength of the blends increased. However, at a high POE content, the tensile and flexural strengths decreased, seemingly because of the lower mechanical properties of POE.