Carbon black‐filled polyolefins as positive temperature coefficient materials: The effect of<i>in situ</i>grafting during melt compounding

Hou, Yan Hui; Zhang, Ming Qiu; Rong, Min Zhi

doi:10.1002/polb.10357

Cited by 16 publications

(7 citation statements)

References 13 publications

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“…The higher is the grafting monomer dosage, the higher the grafting percentage is, demonstrating the appropriateness of the calculation of φ g1 and φ g2 . Considering the results of FTIR–ATR, as well as X‐ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (FTIR–TGA) measurements reported in our previous paper,21 it is believable that the grafting monomer is grafted onto the CB surface. Moreover, it is understood from Table I that even if the dosage of grafting monomer is same, the grafting percentages vary with the types of the monomers, and AA gives the highest grafting percentage.…”

Section: Resultsmentioning

confidence: 90%

“…It is assumed that the presence of direct bridging chain, a single chain adsorbed on two separate aggregate, is responsible for the appearance of the plateau. In our previous study,21 we obtained in situ melt‐grafted‐CB filled LDPE composites and studied the electrical properties of the composites. In the present article, we pay our attention to the effect of different species of grafting monomers on the viscoelastic behavior of the composites at both melt and solid state.…”

Section: Introductionmentioning

confidence: 99%

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Dynamic viscoelasticity of low‐density polyethylene/in‐situ‐grafted carbon black composite

Zheng

Zhang³

et al. 2006

J of Applied Polymer Sci

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ABSTRACT:The study on the dynamic viscoelastic properties of grafted carbon black (g-CB) filled low-density polyethylene (LDPE) was carried out. Because of formation of CB networking, the characteristic modulus plateau and loss tangent arc appears. Addition of grafting monomer like butyl acrylate (BA) and acroleic acid (AA) enhances the interaction between particles and matrix due to accelerated formation of micronetworking in the composites induced by forming branch chains of AA and BA with multiunit. The decrease of the temperature corresponding to ␣ c mechanical relaxation together with AA (BA) addition given by the position of loss tangent (tan ␦) peak for LDPE is owed to the formation of long-chain polymer grafted between CB and the matrix, which facilitates the slip of the lamella of LDPE. The influence of maleic anhydride (MA) on enhancing interaction between LDPE and CB is not so pronounced, as compared with AA and BA because of no formation of long chain between CB particle and polymer matrix.

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Section: Resultsmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Dynamic viscoelasticity of low‐density polyethylene/in‐situ‐grafted carbon black composite

Zheng

Zhang³

et al. 2006

J of Applied Polymer Sci

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“…8 shows the plots of DC resistivity (reciproal of DC conductivity) against temperature for HDPE/PS/1.1 vol% CNF composite, normalized to its corresponding value at 25 °C. The resistivity remains almost unchanged at low temperatures (< 40 °C), and thereafter increases rapidly with increasing temperature, showing a positive temperature coefficient effect at temperature above 115 ºC [14][15][16][17][18]. This effect arises from the macromolecular segments begining to relax as the testing temperature is increased, leading to the disruption of percolating CNF paths embedded within polymer matrix.…”

Section: Electrical Behaviormentioning

confidence: 99%

Fabrication and electrical conducting behavior of carbon nanofiber reinforced high-density polyethylene/ polystyrene nanocomposites with low percolation threshold

Liang¹,

Bao²,

Tjong

2008

E-Polymers

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Ternary high-density polyethylene/polystyrene/carbon nanofiber nano composites were fabricated by melt-compounding. The effect of melt compounding sequences on electrical conducting behavior of such composites was examined. Two compounding sequences were adopted in this study. Route I consisted of an initial melt mixing of HDPE and PS, followed by blending with CNFs. Route II involved an initial formation of the PS/CNF master batch, followed by blending with HDPE. The results showed that CNFs were dispersed in HDPE phase of Route I prepared HDPE/PS/CNF nanocomposites whilst they resided in PS phase of Route II formed nanocomposites. Electrical measurement showed that Route II prepared nanocomposites had a low percolation concentration of 1.1 vol% CNF.

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“…However, a great disadvantage associated with a sharp negative temperature coefficient (NTC) effect in CB filled semicrystalline polymer composites limits their application in over‐temperature protections 12. Crosslinking of the semicrystalline polymer matrix by peroxide, gamma radiation, or electron beam has been reported to eliminate the NTC effect 13, 14. Chan et al15, 16 have reported that presence of very high molecular weight PE in (UHMWPE–CB) and (UHMWPE–PP–CB) composites could eliminate the NTC effect even though they were not crosslinked.…”

Section: Introductionmentioning

confidence: 99%

Effect of coefficient of thermal expansion on positive temperature coefficient of resistivity behavior of HDPE–Cu composites

Kar¹,

Khatua²

2010

J of Applied Polymer Sci

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Positive temperature coefficient of resistivity (PTCR) characteristics of (high density polyethylene) HDPE-Cu composites has been investigated with reference to the conventional HDPE-CB (carbon black) composites. Plot of resistivity against temperature of HDPE-CB composites showed a sudden rise in resistivity (PTC trip) at 127 C, close to the melting temperature of HDPE. However, the PTC trip temperature (98 C) for HDPE-Cu composites was appeared well below the melting temperature of HDPE. Addition of 1 phr nanoclay in the composites resulted in an increase in PTC trip temperature of HDPECu composites, whereas no significant effect of nanoclay on PTC trip temperature was evident in case of HDPE-CB-clay composites. We proposed that the PTC trip temperature in HDPE-Cu composites was governed by the difference in coefficient of thermal expansion (CTE) of HDPE and Cu. The room temperature resistivity and PTC trip temperature of HDPE-Cu composites were very much stable upon thermal cycling. DMA results showed higher storage modulus of HDPE-Cu composites than the HDPE-CB composites. Thermal stability of HDPE-Cu composites was also improved compared to that of HDPE-CB composites.

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Carbon black‐filled polyolefins as positive temperature coefficient materials: The effect ofin situgrafting during melt compounding

Cited by 16 publications

References 13 publications

Dynamic viscoelasticity of low‐density polyethylene/in‐situ‐grafted carbon black composite

Dynamic viscoelasticity of low‐density polyethylene/in‐situ‐grafted carbon black composite

Fabrication and electrical conducting behavior of carbon nanofiber reinforced high-density polyethylene/ polystyrene nanocomposites with low percolation threshold

Effect of coefficient of thermal expansion on positive temperature coefficient of resistivity behavior of HDPE–Cu composites

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