• Elastomers and Composites
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• v.57 no.3
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• pp.107-113
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• 2022

The effects of fillers [talc, calcium carbonate, glass fiber, and EBR (ethylene-butene rubber)] on the shrinkage and mechanical properties of injection-molded polypropylene composites were investigated. The shrinkage correlated with the shape of the filler particles: at the same amount added, glass fibers with a large aspect ratio had the greatest effect on the shrinkage of polypropylene composites, followed by flake-shaped talc and granular calcium carbonate. It was confirmed that the addition of EBR rubber as an impact strength modifier reduced shrinkage proportionally to the added content. In addition, the addition of glass fiber resulted in the greatest increases in tensile and flexural strengths.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.290-290
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• 2006

The toughening mechanisms of polypropylene (PP) containing 9.2 vol % of calcium carbonate ($CaCO_{3}$) nanoparticles were investigated using optical microscopy and transmission electron microscopy. Double-notch four-point bending (DN-4PB) Charpy impact specimens were utilized to study the fracture mechanism(s) responsible for the observed toughening effect. A detailed investigation reveals that the $CaCO_{3}$ nanoparticles act as stress concentrators to initiate massive crazes, followed by shear banding in PP matrix. These toughening mechanisms are responsible for the observed improved impact strength.

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.771-776
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• 1997

The various shape of calcium carbonate were prepared. For the preparation of the PP/$CaCO_3$ composite, these synthetic calcium carbonate(cubic, spheric and neddle type) and PP were mixed on a two roll mill and the mixture were pressed into plate. The effect of particle shape in the prepared composite on the crystallization temperature, heat of fusion, size of spherulite and mechanical properities were investigated. It was found that the former four were strongly influenced by that. When, especially, vaterite was mixed with PP, the size of spherulite was smaller and the degree of crystallinity was higher than others. Therefore, the tensile strength and Young's modulus were higher.

• Journal of Adhesion and Interface
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• v.14 no.4
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• pp.175-182
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• 2013

In this work, we aim to investigate the specific gravity, thermal, and mechanical property changes of solid-state extruded polypropylene (PP)/calcium carbonate composites before and after orientation. For this work, we prepared $PP/CaCO_3$ composites having two different sizes (OM-1 and OM-10). On increasing the filler content, the specific gravity of the composites increases. The specific gravity of the oriented specimen containing filler in PP matrix is found to be much smaller than that of pre-specimen due to the formation of more microvoids. The presence of microvoids in case of oriented composite specimen significantly affected the tensile and flexural properties of the composites. It was observed that the effect of orientation on both flexural strength and modulus is much stronger than the effect of filler contents, regardless of the filler particle size.

• Advances in materials Research
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• v.5 no.2
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• pp.121-130
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• 2016

In an attempt to reach a balance of performances in homo-polypropylene based system, the effects of single and hybrid reinforcements inclusions comprising calcium carbonate nanoparticles (2, 4 and 6 phc) and glass fibers (10 wt.%) on the mechanical and thermal properties were investigated. Different samples were prepared by employing twin-screw extruder and injection molding machine. In morphological studies, the uniform distribution of glass fibers in PP matrix, relative adhesion between glass fibers and polymer, and existence of nanoparticles in polymer matrix were observed. $PP/CaCO_3$ (6 phc) as compared to pure PP and PP/GF had superior tensile and flexural strengths, impact resistance and deformation temperature under load (DTUL). $PP/GF/CaCO_3$ (6 phc) composite displayed comparable tensile and flexural strengths and impact resistance to neat PP, while its tensile and flexural moduli and deformation temperature under load (DTUL) were 436%, 99% and $26^{\circ}C$greater respectively. The maximum impact resistance was observed in $PP/CaCO_3$(6 phc). The highest DTUL was perceived in PP hybrid nanocomposite containing 10 wt.% glass fiber and 4 phc $CaCO_3$ nanoparticle.

• Polymer(Korea)
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• v.39 no.3
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• pp.382-387
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• 2015

The dispersion of calcium carbonate ($CaCO_3$) in polypropylene (PP) and the effect of $CaCO_3$ size on the crystallinity of PP were studied. Polymer composite usually suffers from the brittleness when reinforced with inorganic fillers. The problem is generally related to the size and dispersion of fillers. First, the dispersion was studied for the nanosize $CaCO_3$ with 15~40 nm average diameter. To enhance the dispersibility in PP, the surface of the $CaCO_3$ was treated with sodium lignosulfonate (SLS). $CaCO_3$/PP composites were prepared via melt compounding. The $CaCO_3$ coated with more than 3 wt% SLS was uniformly distributed within the PP matrix, while the uncoated $CaCO_3$ formed aggregated structures in the PP. Even with 30 wt%, the SLS-$CaCO_3$ was well dispersed in the PP matrix. Also, the transition enthalpy of $CaCO_3$/PP increased and the full-width of half maximum of the crystallization peak decreased regardless of SLS coating and size of $CaCO_3$. However, the crystallinity of PP was more influenced by nano $CaCO_3$. These results imply that the nano $CaCO_3$ coated with SLS may reduce the brittleness of polymer composites.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.30 no.3
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• pp.220-226
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• 1994

In this paper the failure mechanisms of polypropylene resin composites filled with calcium carbonate particulates have been studied in the temperature range $-50^{\circ}C$ to $-50^{\circ}C$ The fillers used are both untreated and surface treated with stearic acid. The impact fracture toughness is evaluated from the impact energy absorbed divided by the uncut ligament area of the specimen. Impact fracture toughness increases as temperature is raised whether the fillers are coated or not. The static fracture toughness of these particular composites is evaluated based on the linear clastic fracture toughness of these particular composites is evaluated based on the linear clastic fracture mechanics. Static fracture toughess decreases with increasing temperature whether the fillers are coated or not. An extended stress whitened zone are observed through a large number of availabel sites for cavitation/debonding along particle matrix interface and matrix deformation.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.471-476
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• 2000

Long-term behavior of reinforced clayey soil by model tests were performed to investigate the effect of reinforcement during loads and under static loads. In order to determine proper contents by weight of monofilament polypropylene fiber and calcium carbonate, the drying shrinkage and compressive strength tests had been conducted before model tests. Model tests were run on a clayey soil mixed with or without reinforcement and test specimen in test apparatus was placed in air dry for 7days before load application. In the case of fiber reinforced soil, the horizontal strain was lower than others during loads because the presence of fibers increased the soil's resistance to deformation. All of reinforced clayey soil, horizontal strain decreased as the water content decrease under static loads.

• KSBB Journal
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• v.20 no.1 s.90
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• pp.18-20
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• 2005

Polypropylene carbonate-polyvalerolactone(PPC-PVL) and polyvalerolactone (PVL) produced from exhausted carbon dioxide were degraded by Stenotrophomonas maltophilia separated from soils of waste landfill. The biodegradation was confirmed by FTIR spectrum. PPC-PVL and PVL were degraded $6.6\%,\;12\%$ respectively, at 28 days of pure Stenotrophomonas maltophilia culture.

• Journal of Energy Engineering
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• v.19 no.4
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• pp.221-227
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• 2010

In this study, we consider gas generation characteristics on pyrolysis of eco-fuel which were made by mixing of Pitch Pine and Lauan sawdust as biomass and polyethylene, polypropylene, polystyrene as municipal plastic wastes with catalyst in fixed bed reactor. From the result of higher heating value(HHV) measurement and of ultimate analysis, the heating value of plastic wastes and a hydrogen content in plastic sample are higher than biomass. An activation energy was reduced by a catalyst addition. However the catalyst content influence over 5 wt% was insignificant. The yield of hydrogen from gasification of biomass containing plastic wastes such as polyethylene, polypropylene and polystyrene were obtained higher than that of sole biomass. The high temperature and mixture ratio of catalyst conditions induced to high hydrogen yield in most of the samples. As the influence of catalyst, the hydrogen yield by catalytic reaction was higher than non-catalytic reaction. We confirmed that Ni-$ZrO_2$ catalyst is more active in increasing the hydrogen yield in comparison with that of carbonate catalyst. The maximum hydrogen yield was 65.9 vol.%(Pitch Pine / polypropylene / 20 wt.% Ni-$ZrO_2$(1:9) at $900^{\circ}C$).