A study on electrical conductivity and impact property of carbon black / high impact polystyrene compounds

การศึกษาสมบัติการนำไฟฟ้าและสมบัติต้านทานแรงกระแทกของคอมพาวด์ระหว่างผงเขม่าดำกับพอลิสไตรีนชนิดต้านทานแรงกระแทกสูง

Name: Sorraya Phiboonkulsumrit

Organization : King Mongkut's University of Technology Thonburi. School of Energy, Environment and Materials. Materials Technology

keyword: Conductive Compounds

; พลาสติกนำไฟฟ้า

; การนำไฟฟ้า

; Electric conductors

; Carbon-black

Abstract: The main purpose of this study is to develop CB/HIPS conductive compound used for Electrostatic Discharge (ESD) control in electronic packaging application. In Thailand, compound industries producing conductive plastics have confronted with several quality problems. In the case of high impact polystyrene (HIPS) filled with carbon black (CB),used mainly for IC shipping tray and packaging for electronic parts, local compounders as well as the packaging fabricators have found inferior impact performances of products produced from the local CB/HIPS compounds. Impact strength of CB/HIPS films or sheets are -70 % lower than those of the neat HIPS. In addition to the unsatisfactory impact property, local CB/HIPS compounds often show non-uniform surface resistivity problem, possibly, due to poor dispersion and distribution of carbon black, and loss of carbon black particles from product surfaces, known as 'sloughing'. In searching for a practical solution for these CBMIPS problems, efforts were made in this study to learn and develop effective CB/HIPS compound with desirable conductive and impact properties utilizing twin screw extrusion technique. Preliminary findings on compound development using a lab-scale counter-rotating twin screw extruder revealed that screw speeds used in mixing process and CB content had critical effects on the electrical 'konductivity behavior of compounds. Additional attempt involved studying effects of screw designs and improving compounding capacity by using a pilot scale corotating twin screw extruder. Results showed that screw configuration used in compounding process had vital influences on electrical conductivity and surface properties of CBHIPS compounds. Changes of screw speeds showed no significant effects on impact strength, but increasing CB content decreased impact strength of the CBJHIPS compounds. Based on the results from this study, CBHIPS compounds, having desirable surface resistivity in the optimum ESD control range of lo6-10' ohmisquare could be achieved using less CB (-5 phr) as compared to the currently produced local compounds. Improvement in impact property of -30% over that of the local compound was also observed for these developed CB filled HIPS, an average impact strength value was 4.47 mJ/rnm2. Overall results demonstrated that the screw design containing 2 kneading zones with a long kneading block, at the melt mixing stage, was suitable for dispersive and distributive mixing of CB in HIPS, which resulted in uniform and enhanced electrical conductivity of the compounds.

King Mongkut's University Technology Thonburi. Library

Address: Bangkok

Email: info.lib@mail.kmutt.ac.th

Name: Nandh Thavarungkul

Role: Advisor

Name: Wannee Chinsirikul

Role: Advisor

Created: 2004

Issued: 2007-07-23

Modified: 2013-11-27

วิทยานิพนธ์/Thesis

ISBN: 9741836163

CallNumber: MT231

eng

DegreeName: Master of Engineering

Level: Master's Degree

Descipline: Materials Technology

Grantor: King Mongkut's University of Technology Thonburi

©copyrights King Mongkut's University of Technology Thonburi

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3	MT231ab.txt	2.96 KB	51	2018-05-10 18:11:29

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