Efficient Thermal Stabilization of Polyvinyl Chloride with Tannin-Ca Complex as Bio-Based Thermal Stabilizer

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 (T op) 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.

Study on the role of tannic acid–calcium oxide adduct as a green heat stabilizer as well as reinforcing filler in the bio‐based hybrid polyvinyl chloride–thermoplastic starch polymer composite

“…The antioxidant property of TA present in the complex could also be regarded as an added advantage in stabilizing the PVC during melt processing. [ 37 ] RW (%) values for TPST15 were found maximum among the composites. The higher char might have hindered the movement of degraded products making it more thermally stable.…”

“…In one report, Tannin–Calcium oxide complex has been cited and tested as a heat stabilizer against PVC in a relatively low proportion. [ 37 ] But no detailed investigation pertaining to its effect on various properties of composites has been reported.…”

Various Combinations of Flame Retardants for Poly (vinyl chloride)

“…Figure 4 shows the DSC curves of PVC samples. The degradation of PVC is an endothermic reaction (Table 3) because the degradation process consists of elimination reactions and takes place as reverse to the organic addition reactions that can occur into the double bond of alkenes [22]. The degradation peak temperatures and heat of degradation of PVC samples were presented in Table 3.…”

Tannin-Ca Complex as Green Thermal Stabilizer Additive for PVC: Viscoelastic Properties

“…They have been historically used in the leather tanning and adhesives industries. Condensed tannins, Figure 1(a), primarily, are polyphenolic oligomers based on flavanyl repeat units with the hydroxylation pattern providing potent antioxidant activity [10] and for some metal ions chelating ability [11] (Figure 1(b) [12]).…”

“…The present study was directed to study the effect of tannins based thermal stabilizer on the viscoelastic properties (DMTA) of PVC. Tannin-Ca complex was synthesized and characterized by our previous study [12].…”