TITLE:
Tannin-Ca Complex as Green Thermal Stabilizer Additive for PVC: Viscoelastic Properties
AUTHORS:
Hussein A. Shnawa, Yousef Jahani, Moayad N. Khalaf, Abed Alamer H. Taobi
KEYWORDS:
PVC, Viscoelastic Properties, Tannin-Ca Complex, Thermal Stability, Tg
JOURNAL NAME:
Open Journal of Organic Polymer Materials,
Vol.5 No.3,
May
18,
2015
ABSTRACT: This study investigated the viscoelastic and rheometeric properties of PVC stabilized with tannin-Ca complex as totally bio-based thermal stabilizer. Dynamic mechanical thermal analysis (DMTA)
used to characterize the viscoelastic properties of PVC samples obtained by thermal mixing of PVC
with three composition percentages (1.0, 2.0, and 3.0) part per hundred ratios (phr) of tannin-Ca
complex with this polymer. The torque rheometery test used to monitor the effect of tannins derivative
on the thermal stability and mixing properties of PVC formulations during samples
processing. For that purpose, PVC sample with 2 phr commercial thermal stabilizer (Reapak B-NT/
7060) was used for comparison and considered as reference samples. Before the glass transition
temperature of PVC at 30°C - 60°C, the DMTA curves show that the values of storage modulus and
tan delta of PVC samples stabilized with tannin derivative were very similar with those of PVC
sample stabilized with commercial thermal stabilizer. The glass transition temperature (Tg) of
PVC stabilized with commercial thermal stabilizer and with tannin-Ca complex occurred at about
76°C. In a sequence, after the glass transition region of PVC samples, the DMTA scans confirmed
that the PVC samples with 2 phr tannin-Ca complex have relatively longer flowing stage which occurs
at lower temperatures by 18°C per that of PVC sample stabilized with commercial stabilizer.
Global results of the torque rheometery which have suitable plateau stages and the DMTA show
that the processing thermal stability and thermal flexibility of PVC are clearly increased with the
incorporation of tannin-Ca complex. All the PVC formulations with tannins-Ca complex show excellent
viscoelastic properties which were found to be slightly best or much closed to those obtained
for PVC stabilized with commercial thermal stabilization.