Characterization of Polypropylene Modified by Blending Elastomer and Nano-Silica

Chi, Xiaohong; Cheng, Lu; Liu, Wenfeng; Zhang, Xiaohong; Li, Shengtao

doi:10.3390/ma11081321

Cited by 45 publications

(35 citation statements)

References 24 publications

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“…Although nanosilica may bring about a mild increase in nucleation density (as will be discussed in the DSC section), the XRD data indicate no major differences in the crystalline phase structure or total crystallinity upon incorporation of neat or plasma modified nanosilica in the injection molded PP/POE composites. The relative β-form PP contents, approximated from the fitted crystalline peaks using the Turner-Jones β-form crystal index [35], were negligible (k β~0 .03) and showed no clear dependence on nanosilica; while silica nanoparticles have been reported to increase β-form PP crystallinity in some polymer composite systems elsewhere [36], this is apparently not the case for the materials studied here. Figure 11.…”

Section: Xrd Crystalline Structure Analysismentioning

confidence: 60%

Surface Modification of Fumed Silica by Plasma Polymerization of Acetylene for PP/POE Blends Dielectric Nanocomposites

Rytöluoto

Anyszka

et al. 2019

Polymers

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Novel nanocomposites for dielectric applications-based polypropylene/poly(ethylene-co-octene) (PP/POE) blends filled with nano silica are developed in the framework of the European ‘GRIDABLE’ project. A tailor-made low-pressure-plasma reactor was applied in this study for an organic surface modification of silica. Acetylene gas was used as the monomer for plasma polymerization in order to deposit a hydrocarbon layer onto the silica surface. The aim of this modification is to increase the compatibility between silica and the PP/POE blends matrix in order to improve the dispersion of the filler in the polymer matrix and to suppress the space charge accumulation by altering the charge trapping properties of these silica/PP/POE blends composites. The conditions for the deposition of the acetylene plasma-polymer onto the silica surface were optimized by analyzing the modification in terms of weight loss by thermogravimetry (TGA). X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray fluorescence spectroscopy (EDX) measurements confirmed the presence of hydrocarbon compounds on the silica surface after plasma modification. The acetylene plasma modified silica with the highest deposition level was selected to be incorporated into the PP/POE blends matrix. X-ray diffraction (XRD) showed that there is no new crystal phase formation in the PP/POE blends nanocomposites after addition of the acetylene plasma modified silica. Differential scanning calorimetry results (DSC) show two melting peaks and two crystallization peaks of the PP/POE blends nanocomposites corresponding to the PP and POE domains. The improved dispersion of the silica after acetylene plasma modification in the PP/POE blends matrix was shown by means of SEM–EDX mapping. Thermally stimulated depolarization current (TSDC) measurements confirm that addition of the acetylene plasma modified silica affects the charge trapping density and decreases the amount of injected charges into PP/POE blends nanocomposites. This work shows that acetylene plasma modification of the silica surface is a promising route to tune charge trapping properties of PP/POE blend-based nanocomposites.

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Section: Xrd Crystalline Structure Analysismentioning

confidence: 60%

Surface Modification of Fumed Silica by Plasma Polymerization of Acetylene for PP/POE Blends Dielectric Nanocomposites

Rytöluoto

Anyszka

et al. 2019

Polymers

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“…The storage moduli of the SEBS/PP composites and LDPE decrease with the increase of the temperature, which is due to exacerbation in the activity of the molecular chains caused by temperature elevation. Since the storage modulus is related to the general elastic deformation caused by changes in the bond length and bond angle of the molecular chains, the high crystallinity will generally lead to a higher storage modulus, accounting for the higher storage modulus of the SEBS/PP composites than that of LDPE [ 18 ]. The PP crystallinity decreases after blending the amorphous elastomer SEBS to form the island phase in the composites and is vulnerable to external forces, which results in a significant abatement in the storage modulus.…”

Section: Resultsmentioning

confidence: 99%

Improved Water-Tree Resistances of SEBS/PP Semi-Crystalline Composites under Crystallization Modifications

et al. 2020

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Water-tree resistances of styrene block copolymer/polypropylene (SEBS/PP) composites are investigated by characterizing crystallization structures in correlation with the dynamic mechanical properties to elucidate the micro-structure mechanism of improving insulation performances, in which the accelerated aging experiments of water trees are performed with water-knife electrodes. The water-tree morphology in spherulites, melt-crystallization characteristics and lamella structures of the composite materials are observed and analyzed by polarizing microscopy (PLM), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM), respectively. Dynamic relaxation and stress-strain characteristics are specifically studied by means of a dynamic thermomechanical analyzer (DMA) and electronic tension machine, respectively. No water-tree aging occurs in both the highly crystalline PP and the noncrystalline SEBS elastomer, while the water trees arising in SEBS/PP composites still has a significantly lower size than that in low-density polyethylene (LDPE). Compared with LDPE, the PP matrix of the SEBS/PP composite represent a higher crystallinity with a larger crystallization size in consistence with its higher mechanical strength and lower dynamic relaxation loss. SEBS molecules agglomerate as a “island” phase, and PP molecules crystallize into thin and short lamellae in composites, leading to the blurred spherulite boundary and the appreciable slips between lamellae under external force. The high crystallinity of the PP matrix and the strong resistance to slips between lamellae in the SEBS/PP composite essentially account for the remarkable inhibition on water-tree growth.

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“…Various inorganic nanoparticles, including ZnO, SiO 2 , SiC, TiO 2 , MgO, LSMO, and zeolite, have been used to inhibit space charge accumulation in nanocomposites. The addition of these inorganic nanoparticles suppresses the accumulation of space charge, reduces the electrical conductivity, and increases the breakdown strength of insulating materials to various degrees [5][6][7][8][9][10][11][12][13][14][15]. This has been attributed to the introduction of deep trapping states resulted from the generated interface regions by nanoparticles, which can largely reduce charge carrier mobility.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Space Charge and DC Breakdown Behavior of XLPE/α-Al2O3 Nanocomposites

Guo

Xing²,

Zhao

et al. 2020

Materials

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This paper describes the effects of α-Al2O3 nanosheets on the direct current voltage breakdown strength and space charge accumulation in crosslinked polyethylene/α-Al2O3 nanocomposites. The α-Al2O3 nanosheets with a uniform size and high aspect ratio were synthesized, surface-modified, and characterized. The α-Al2O3 nanosheets were uniformly distributed into a crosslinked polyethylene matrix by mechanical blending and hot-press crosslinking. Direct current breakdown testing, electrical conductivity tests, and measurements of space charge indicated that the addition of α-Al2O3 nanosheets introduced a large number of deep traps, blocked the charge injection, and decreased the charge carrier mobility, thereby significantly reducing the conductivity (from 3.25 × 10−13 S/m to 1.04 × 10−13 S/m), improving the direct current breakdown strength (from 220 to 320 kV/mm) and suppressing the space charge accumulation in the crosslinked polyethylene matrix. Besides, the results of direct current breakdown testing and electrical conductivity tests also showed that the surface modification of α-Al2O3 nanosheets effectively improved the direct current breakdown strength and reduced the conductivity of crosslinked polyethylene/α-Al2O3 nanocomposites.

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Characterization of Polypropylene Modified by Blending Elastomer and Nano-Silica

Cited by 45 publications

References 24 publications

Surface Modification of Fumed Silica by Plasma Polymerization of Acetylene for PP/POE Blends Dielectric Nanocomposites

Surface Modification of Fumed Silica by Plasma Polymerization of Acetylene for PP/POE Blends Dielectric Nanocomposites

Improved Water-Tree Resistances of SEBS/PP Semi-Crystalline Composites under Crystallization Modifications

Investigation of the Space Charge and DC Breakdown Behavior of XLPE/α-Al2O3 Nanocomposites

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