• Fire Science and Engineering
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• v.15 no.1
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• pp.16-22
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• 2001

Thermal properties of PP and LLDPE dusts from chemical plant and their risks of coexisting with oxidizer were investigated by a pressure vessel. The thermal decomposition of PP and LLDPE dusts with temperature using DSC and the weight loss with temperature using TGA were also investigated to find the thermal hazard of PP and LLDPE dusts. Using the pressure vessel which can estimate ignition and explosion of PP and LLDPE dusts coexisting with oxidizer, a series of bursting of a rupture disc, experiments has been conducted by varying the orifice diameters the weight ratio of the sample coexisting with oxidizers and the species of oxidizer. And fire gases was measured by gas analyser ($ECOM-A^+$). According to the results of the thermal analysis of PP and LLDPE dusts, the decomposition temperature range of PP and LLDPE dusts was 200 to 350 and 300 to $500^{\circ}c$, respectively. The risk of PP and LLDPE dusts coexisting with oxidizer was increased as the orifice diameter was decreased. On the other hand, it was increased as the weight ratio of the sample to the oxidizer were increased. In addition, the risk of PP and LLDPE dusts coexisting with oxidizer was affected by the decomposition temperature of the sample and oxidizer. It is found that the risk of fire becomes high when the decomposition temperature of the sample is about same as that of oxidizer. Also, the fire gases was occurred carbon monoxide and carbon dioxide. The amount of carbon monoxide generated was found to be much higher in PP decomposition than in LLDPE due to incomplete combustion of PP which has high content of carbon in chemical compound.

• Journal of Adhesion and Interface
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• v.6 no.2
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• pp.1-5
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• 2005

Single crystals of metallocene-catalyzed isotactic polypropylene (iPP) and/or syndiotactic PP (sPP) were prepared and preliminarily characterized. The crystallization was performed utilizing 0.1 % by weight concentrations of each PP in o-xylene in the range of temperature of $40{\sim}90^{\circ}C$. Following the XRD patterns, samples were ${\alpha}$-iPP and antichiral Cell III of sPP. The XRD pattern of iPP shows three ${\alpha}$-form peaks due to the (110), (040), (130) planes at $2{\theta}=14.2^{\circ}$, $17^{\circ}$, $18.8^{\circ}$, respectively. The XRD pattern of sPP is characterized by the presence of the (020) reflection at $16^{\circ}$. The melting point ($123^{\circ}C$ and $148^{\circ}C$, respectively) of the metallocene catalyzed iPP and sPP were generally lower than that of conventional PP ($160{\sim}170^{\circ}C$) due to the misinsertion of the monomer. When metallocene-catalyzed iPP samples were crystallized isothermally from solution grown at a lower temperature, lozenge shape single crystals were observed by transmission electron microscopy (TEM).

• Polymer(Korea)
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• v.38 no.5
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• pp.613-619
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• 2014

The polypropylene/polyamide elastomer (PP/PAE) blends were prepared by melt mixing. PP and PAE in PP/ PAE were immiscible completely. The size of PAE domains was large and the clear gap in the interface between PP and PAE existed, which did not meet the conditions enhancing toughness of polymers by elastomer. Therefore, maleic anhydride grafted polypropylene (MP) was used to improve the miscibility between PP and PAE. The miscibility between PP and PAE was improved and the size of dispersed phase PAE decreased by introducing MP. The crystallization of PP became easier by introducing PAE as a nucleating agent. With the increase of PAE content, the melt-crystallization temperatures of PP components in PP/PAE/MP blends increased gradually. The melt-crystallization of the polytetramethylene oxide segment of PAE component in PP/PAE blends were hampered by PP component. In addition, PAE can enhance significantly the toughness of PP, and the tensile strength and modulus did not decrease.

• Elastomers and Composites
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• v.38 no.2
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• pp.122-127
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• 2003

Compounding, using such thermoplastic elastomer as styrene-ethylene-butadiene-styrene (SEBS) blended with polypropylene(PP), oil, and other ingredients, was studied to develop a new material with excellent impact resistance and resilience for the replacement of environmentally toxic PVC sheet. Hardness decreased linearly with oil content in the SEBS/oil blend, and the tensile strength increased with PP content whereas elongation showed no effects over 50 phr of PP in SEBS/oil/PP blend. In the practical SEBS composition, proposed to replace the PVC sheet material, tensile and tear strength, as well as hardness, increased proportionally with PP content, while melt index decreased.

• Applied Chemistry for Engineering
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• v.33 no.5
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• pp.471-476
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• 2022

PP/KF felt was used to load a high content of kenaf fiber (KF) into polypropylene (PP), and polyurethane (PU) was used as a binder. In order to find an optimum composition ratio of the PU binder, the flexural strength of the PP/KF/PU felt composite according to the isocyanate and polyol ratio was evaluated. PP-g-MAH grafted with maleic anhydride (MAH) was applied as a compatibilizer. Tensile, flexural, and impact properties were evaluated to consider changes in mechanical properties of the PP/KF/PU felt composite, and the properties were improved.

• Polymer(Korea)
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• v.35 no.1
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• pp.17-22
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• 2011

Polypropylene/multi-walled carbon nanotube(PP/MWCNT) composites along with various MWCNT contents up to 20 wt% were prepared by a twin screw extruder. Nanocomposites having 20 wt% MWCNT as a master batch(M/B) were diluted with PP by way of melt compounding. The electrical/thermal conductivity, morphology, thermal/viscoelastic/mechanical properties were investigated with the variation of MWCNT contents. Also, we compared some properties between 1-step PP/MWCNT and the diluted PP/MWCNT composites. The percolation threshold of electrical and thermal conductivity was measured at about 3 wt% MWCNT. And conductivity of diluted PP/MWCNT composites were superior to those of PP/MWCNT composites. The non-isothermal crystallization temperature and thermal decomposition temperature appeared at higher temperatures with increasing MWCNT contents. Morphology showed that length of MWCNT in diluted PP/MWCNT composites was shortened by twice melt blending, which contributed to improve the tensile strength of PP/MWCNT composites.

• Polymer(Korea)
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• v.37 no.4
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• pp.494-499
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• 2013

Modified polypropylene (m-PP) was fabricated by furfuryl sulphide (FS) as branching agent and m-PP/nano-filler composites were prepared with silicate and multi-walled carbon nanotube (MWCNT), using a twin screw extruder. The chemical structures and thermal properties of the m-PP were investigated by FTIR and DSC. The chemical structure of the m-PP was confirmed by the existence of =C-H stretching peak of the branching agent at 3100 $cm^{-1}$. There was no district change in melting temperature in case of m-PP, but a certain increase in crystallization temperature was notified and the increase was in the range of $10-20^{\circ}C$. The rheological properties, filler dispersion and foaming behaviors of the m-PP/nano-filler composites were investigated by dynamic rheometer, X-ray diffractometer (XRD) and scanning/transmission electron microscope (SEM/TEM). m-PP/nano-filler composites showed a high complex viscosity at a low frequency, an increase in melt elasticity, and a high shear thinning effect. Compared to pure PP, m-PP and m-PP/nano-filler composites were sufficient to enhance the foaming behavior.

• Journal of the Korean Data and Information Science Society
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• v.19 no.3
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• pp.913-924
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• 2008

The purpose of this study is to categorize Program Provider(PP) outside and inside of the country systematically under the notion that the categorization system of the strategy group for PP is not properly organized. In this paper, not only Commercial PP but also Public PP and Homeshopping PP are also included and PP Company is consistently classified and reorganized as a strategy group in the level of contents, because existing positive study does not entirely deliberate over the characteristics of the PP contents industry inside the country. According to this frame, it is classified into 6 contents group-oriented PP strategy groups using 14 variables including vertical integration, horizontal integration, the sales, advertising revenue, license revenue, total net revenue, the number of employees and history.

• Journal of the Korean Applied Science and Technology
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• v.30 no.3
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• pp.387-393
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• 2013

The crystallization of polypropylene (PP) particles in PP/decalin solution was conducted using the thermally induced phase separation(TIPS). During the control of particles sizes followed by the cooling of PP/decalin solution, particles were formed controllably, the concentrated PP resulted in an increase in the average diameter of PP particles. The effects of surfactants changes on particles sizes were investigated by using a field emission scanning electron microscope (FE-SEM). The PP crystals showed spherical shapes with a diameter 5~18 ${\mu}m$. Additionally, as an effect of concentration of PP, the size distribution of the PP particles became broad with higher concentration of PP in the solution.

• Journal of the Korean Applied Science and Technology
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• v.15 no.1
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• pp.1-7
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• 1998

Lubricating softner(SOS-2) for permanent press(PP) finish was prepared by blending water, beef tallow hardened oil for improving softness, and the emulsion which was synthesized from N-hexadecanoyl-N,N'-bis(2-hexadecamidoethyl)amine as a softening component and silicone oil KF-96 as a lubricating component. The prepared SOS-2 and the PP finishing resin were applied to PP finishing cotton broad cloth and P/C gingham samples using one bath method. The properties such as tear strength, crease recovery, bending resistance test were tested. The samples treated with SOS-2 and PP finishing resin have improved properties, compared with nontreated samples, those treated only with PP finishing resin, those treated with commercial PP finishing softners and PP finishing resin.