• Polymer(Korea)
• /
• v.38 no.5
• /
• pp.566-572
• /
• 2014

Maleic anhydride (MAH) grafted polypropylenes (PP) (MAH-g-PP) were prepared by changing MAH content and styrene monomer (SM)/MAH mole ratio with different type PP, using a twin screw extruder. The types of PP were isotatic PP (iPP), block PP (bPP), and random PP (rPP) and dicumyl peroxide (DCP) was used as an initiator. The graft degree of MAH was confirmed by the existence of carbonyl group (C=O) stretching peak at $3100cm^{-1}$ of FTIR spectrum. Thermal properties of MAH-g-PP and PP/MAH-g-PP/pulp composites were investigated by DSC and TGA. There was no district change in thermal properties of PP/MAH-g-PP/pulp composites. Based on tensile properties and SEM pictures for fractured surface of PP/MAH-g-PP/pulp composites, MAH-g-rPP was the best as the compatibilizer and optimum formulation was MAH content of 1.0 wt%, SM/MAH mole ratio of 1.0, and melt index (MI) of 25 g/10 min. The rheological properties of the composites were investigated by a dynamic rheometer. The complex viscosity, shear thinning effect, and water uptake incresed with pulp content.

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

• Polymer(Korea)
• /
• v.29 no.1
• /
• pp.19-24
• /
• 2005

Polymer blends containing polypropylene (PP) with compatibilizers were prepared using twin screw extruder. Physical properties were investigated using universal test machine (UTM) and Izod impact tester. In the PP/acrylonitrilebutadiene-styrene (ABS) blends, mechanical strength was increased with the addition of PP-g-styrene acryloritrile (PP-g-SAN) compatibilizer, and the ductility was increased with the addition of ethylene-ethyl acrylate-maleic anhydride (E-EAMAH-g-SAN) compatibilizer. For the PP/ABS/ polycarbonate (PC)/Nylon-6,6 blends, impact strength was increased with the addition of ethylene glycidylmethacrylate (E-GMA compatibilizer) up to 0.5 phr. In the case of the PP/ABS/PC/Nylon-6,6/poly(methyl methacrylate) (PMMA)/poly(oxymethylene) (POM)/poly(vinyl acetate) (PVC)/poly(butylene terephthalate) (PBT) blends, mechanical properties were increased by the complex compatibilizing effects of PP-g-SAN, E-EA-MAH-g-SAN and E-GMA, respectively.

• Resources Recycling
• /
• v.24 no.2
• /
• pp.36-45
• /
• 2015

In this study, various sizes of waste ground rubber tire (WGRT) were devulcanized by a single screw extruder equipped with a sonicator in front of the die, and waste PP and devulcanized waste ground rubber tire (DWGRT) composites were prepared by an intermeshing co-rotating twin screw extruder. The crosslink density and percent devulcanization of WGRT and DWGRT for 40, 80 and 140 meshes were calculated. The mechanical properties of the composites were compared with each other. The effect of SEBS-g-MA as a compatibilizer was investigated on mechanical properties of both waste PP/WGRT and waste PP/DWGRT composites. The crosslink density was decreased with decreasing the WGRT size. On the other hand, the percent devulcanization was increased by adding the smaller size of WGRT. Also, tensile strength, impact strength and elongation at break of the composite with DWGRT were higher than those with WGRT. Especially, mechanical properties of the composites were significantly increased by adding the smaller size of WGRT and DWGRT. Addition of SEBS-g-MA into both waste PP/(D)WGRT composites exhibited better impact strength and elongation at break than the composites themselves.

• Composites Research
• /
• v.30 no.2
• /
• pp.145-148
• /
• 2017

Wood powders were surface-modified by plasma-treating propylene to make them compatible with PP matrix in WPC(wood powder composite). The plasma treatment of propylene resulted in the deposition of an ultrathin hydrophobic film which had the chemical structure similar to that of polypropylene. Wood powder and polypropylene were mixed to pellets by twin screw extruder and then 50 wt% wood powder/PP composites were produced by an injection machine. Tensile strength and flexural strength were improved by 7.59% and 12.43% at the maximum respectively. SEM (Scanning Electron Microscopy) observation on the fracture surface revealed that the treatment improved the interfacial bonding and the mechanical properties of the composites.

• Polymer(Korea)
• /
• v.38 no.2
• /
• pp.250-256
• /
• 2014

Polypropylene (PP) composites containing conductive multi-walled carbon nanotube (MWNT) and stainless steel short fiber (SSF) were manufactured using a twin screw extruder and characterized their surface resistivity and mechanical properties in this work. Surface resistivity measurements showed that the percolation threshold appeared at a lower MWNT loading when a small amount of SSF was added to PP/MWNT composites. Tensile modulus and strength of the composites increased but elongation-at-break decreased greatly compared to pure PP. Also, the effects of MWNT and SSF on storage modulus and tan ${\delta}$ from dynamic mechanical analysis for the composites were examined, and the morphologies of fractured surface and the fillers were observed using a scanning electron microscope.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.6
• /
• pp.275-282
• /
• 2021

High-molecular-weight maleic anhydride-grafted polylactic acids (HMMA-g-PLA) compatibilizers were prepared by melt grafting in a twin screw extruder using di(tert-butyl-perxoyisopropyl)benzene (PK-14; as initiator), maleic anhydride (MA), and divinylbenzene (DVB). To determine the properties of the prepared HMMA-g-PLA compatibilizers, Fourier transform infrared (FTIR), Melt index (MI), and back-titration analyses were performed. On increasing DVB concentration, grafting yield of HMMA-g-PLA increased but MI decreased because 𝛽-scission of PLA was restrained by the DVB, and thus, the molecular weight of HMMA-g-PLA increased. PLA-based wood-plastic composites (WPCs) were prepared using HMMA-g-PLA by melt blending through a single screw extruder. The flexural and impact strengths of WPCs compatibilized with HMMA-g-PLA were greater than those of WPCs produced without HMMA-g-PLA. Scanning electron microscope (SEM) studies indicated that increased mechanical properties were caused by excellent interfacial adhesion between PLA and wood fibers due to the addition of HMMA-g-PLA. However, rather high contents of HMMA-g-PLA reduced the mechanical properties of WPCs. We believe that lower molecular-weight of HMMA-g-PLA added as an compatibilizer, compared with PLA polymer, caused the reduction of mechanical properties.

• Applied Chemistry for Engineering
• /
• v.26 no.3
• /
• pp.336-340
• /
• 2015

Three different types of polycarbonate (PC)/graphene oxide (GO) composites using diphenyl carbonate as a monomer were fabricated by melt polymerization. Those were the PC/GO composite (PC/GO) using a twin extruder, in-situ PC/GO composite (PC/GO-cat.) using a catalyst, and in-situ PC/GO composite (PC/GO-COCl) using a GO-COCl treated by -COCl, Chemical structures of the composites were confirmed by C-H and C=O stretching peak at $3000cm^{-1}$ and $1750cm^{-1}$, respectively. The slope for the storage (G') versus loss (G") modulus plot decreased with an increase in the heterogeneous property of polymer melts. So we can check the GO dispersion of the PC/GO composites using by the slop for G'-G" plot. According to the G'- G" slopes for three different types of PC/GO composites, GO was well dispersed within PC matrix in case of PC/GO and PC/GO-cat.. It was also confirmed by atomic force microscope (AFM) photos. One of the reasons for the poor GO dispersion of PC/GO-COCl is branching and crosslinking processes occurred during polymerization, which was further confirmed by a plot for the complex modulus versus phase difference.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.6
• /
• pp.4039-4045
• /
• 2014

The crystallization behavior of irradiated polypropylene (PP) and the blend is an important parameter for polymer processing. Blends of PP/low density polyethylene (LDPE) with different LDPE contents were prepared by melt mixing in a twin screw extruder. The effect of the LDPE content on the irradiation effectiveness of the PP/LDPE blend with trimethylolpropane-trimetacrylate (TMPTMA) as a crosslinking co-agent was investigated in conjunction with the LDPE loading in the blend. The non-isothermal crystallization and crystal structure were measured by DSC, X-ray diffraction (XRD), and polarized optical microscopy (POM). A decrease in the melting temperature of PP was observed due to irradiation, which may be due to the PP chain scissioning effect of irradiation. The Ozawa component n represents a rod shaped, disc shaped and sphere-shaped geometry of the crystal if the value corresponds to 2, 3 and 4, respectively. Based on Ozawa analysis, the values of n were 3.8 and 2.3 for the pure PP and PP blends with 30 wt% LDPE, respectively. The fact that the crystal geometry of PP changed from spherical to disc and rod shaped was confirmed by Ozawa analysis and POM. The ${\beta}$ form XRD peak of the PP/LDPE blend at $16.1^{\circ}$ disappeared after irradiation due to the crosslinking reaction.

• Polymer(Korea)
• /
• v.30 no.1
• /
• pp.85-89
• /
• 2006

The effect of vapor grown carbon fiber (VGCF) contents on electrical and rheological properties of VGCF filled polyphenylene sulfide (PPS) composites prepared through melt mixing using a twin screw exruder was studied. This method was proved to be quite effective to produce good dispersion of VGCF in the matrix even for highly filled PPS. From the dependence of the electrical conductivity on VGCF content, the percolation phenomena began to occur above $10\;wt\%$. While there is only a marginal increase of viscosity for 1 and $5\;wt\%$ VGCF filled PPS, the composites containing $10\;wt\%$. While VGCF showed abrupt increase in viscosity as well as flattening of frequency vs modulus curve, indicating a transition from a liquid-like to a solid-like behavior due to the creation of VGCF network. This result agrees well to the fact that the network formation in the composite can be composite by rheological property dependence on filler content as well as by electrical conductivity measurement.