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Preparation and characterization of magnesium stearate, cobalt stearate, and copper stearate and their effects on poly(vinyl chloride) dehydrochlorination
Author(s) -
Gönen M.,
Egbuchunam T.O.,
Balköse D.,
İnal F.,
Ülkü S.
Publication year - 2015
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.21384
Subject(s) - stearate , differential scanning calorimetry , vinyl chloride , magnesium stearate , zinc stearate , materials science , calcium stearate , magnesium , cobalt , aqueous solution , copper , thermal decomposition , nuclear chemistry , polymer chemistry , chemistry , organic chemistry , polymer , metallurgy , dosage form , chromatography , composite material , raw material , copolymer , physics , thermodynamics
Preparation and characterization of pure metal soaps and investigation of their effects on poly(vinyl chloride) (PVC) dehydrochlorination were the objectives of the present study. Magnesium stearate (MgSt 2 ), cobalt stearate (CoSt 2 ), and copper stearate (CuSt 2 ) were prepared by a precipitation method. An aqueous sodium stearate (NaSt) solution was mixed at 500 rpm with respective metal salt solutions at 75 o C. The precipitates that formed were collected by filtration, washed with water, and ultimately dried at 105 o C under reduced pressure. Lamellar crystals that melted on heating were obtained. Solid‐liquid phase transitions were observed by optical microscopy at 160 o C, 159 o C, and 117 o C for MgSt 2 , CoSt 2 , and CuSt 2 , respectively. However, the melting points of MgSt 2 , CoSt 2 , and CuSt 2 were determined as 115 o C, 159 o C, and 111 o C, respectively, by analysis by differential scanning calorimetry. The onset temperature of the mass loss was the lowest at 255 o C for CuSt 2 and the lowest activation energy for thermal decomposition was 18 kJ/mol for CuSt 2 . CoSt 2 was effective in extending the induction time of PVC dehydrochlorination at both 140 o C and 160 o C. The activation energy calculated from stability time decreased from 175 kJ/mol for a blank PVC sample to 114, 105, and 107 kJ/mol for MgSt 2 , CoSt 2 , and CuSt 2 ‐containing PVC samples, respectively. All three metal soaps accelerated the dehydrochlorination of PVC. J. VINYL ADDIT. TECHNOL., 21:235–244, 2015. © 2014 Society of Plastics Engineers