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Surface resistivity and mechanical properties of rotationally molded polyethylene/graphite composites
Author(s) -
Mhike Washington,
Focke Walter W.
Publication year - 2013
Publication title -
journal of vinyl and additive technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.295
H-Index - 35
eISSN - 1548-0585
pISSN - 1083-5601
DOI - 10.1002/vnl.21316
Subject(s) - antistatic agent , graphite , materials science , composite material , compounding , electrical resistivity and conductivity , polyethylene , linear low density polyethylene , ultimate tensile strength , molding (decorative) , modulus , compression molding , layer (electronics) , mold , electrical engineering , engineering
Antistatic polymers are required to dissipate static charges safely from component surfaces. Our overall objective has been to develop cost‐effective flame‐retarded and antistatic polyethylene compounds suitable for rotomolding. This communication considers the surface resistivity and mechanical properties of rotationally molded linear low‐density polyethylene (LLDPE)/graphite composites containing natural Zimbabwean graphite, expandable graphite, or expanded graphite. Dry blending and melt compounding were employed to obtain antistatic composites at the lowest graphite contents. Dry blending was found to be an effective mixing method for rotomolding antistatic LLDPE/graphite composites, thereby eliminating an expensive compounding step. Dry‐blended Zimbabwean graphite composites showed the lowest surface resistivity at all graphite contents, with a surface resistivity of 10 5 Ω/square at 10 wt% loading. Although rotomolded powders obtained following the melt compounding of Zimbabwean graphite exhibited higher resistivity values, the variability was much lower. Injection molding resulted in surface resistivity values above 10 14 Ω/square for all compositions used. The rotomolded composites exhibited poor mechanical properties, in contrast to injection‐molded composites. The Halpin‐Tsai model showed good fits to the tensile modulus data for injection‐molded Zimbabwean and expandable graphite. J. VINYL ADDIT. TECHNOL., 19:258–270, 2013. © 2013 Society of Plastics Engineers