TITLE:
Efficient Thermal Stabilization of Polyvinyl Chloride with Tannin-Ca Complex as Bio-Based Thermal Stabilizer
AUTHORS:
Hussein A. Shnawa, Moayad N. Khalaf, Yousef Jahani, Abed Alameer H. Taobi
KEYWORDS:
PVC, Natural Polyphenols, Tannin-Calcium Complex, Bio-Based Thermal Stabilizer
JOURNAL NAME:
Materials Sciences and Applications,
Vol.6 No.5,
May
11,
2015
ABSTRACT: The potential use of tannin-Ca complex derived from tannins as bio-based thermal stabilizer and
antioxidant additive for polyvinyl chloride (PVC) was investigated in this work. For this project,
Reapak B-NT/7060 was applied as reference thermal stabilizer. Variable compositions: (1, 2, and
3) part per hundred ratio (phr) of tannin-Ca complex in the presence of 10 phr Dioctyl phthalate
(DOP) as plasticizer in all PVC formulations were prepared by melt mixing by internal mixer at
165°C. Tannin-Ca complex was characterized by FT-IR spectroscopy, scanning electron microscopy
(SEM) and energy dispersive X-ray analysis (EDX) analysis as well as by means of differential
scanning calorimetry (DSC). The tannin derivative stabilization efficiency under inert atmosphere
was determined by using thermogravimetric analysis (TGA). In addition, its thermal stabilization
effect has been assessed in air as oxidizing atmosphere by DSC in dynamic conditions. According to
TGA thermograms, the initial degradation temperature (Ti) and optimum degradation temperature
(Top) for the main degradation stage of PVC stabilized with this derivative were about 280°C
and 310°C, respectively. While these were about 255°C and 293°C, respectively for PVC stabilized
with commercial thermal stabilizer. Global results of TGA, DSC, SEM and EDX show that the tannin-Ca complex provides the best properties and results in stabilizing both against thermal degradation
and thermal oxidation degradation of PVC.