Melt reaction of polymer blends comprising Poly(ε-Caprolactone) and epoxidized natural rubber with addition of toluene-4-sulfonic acid as catalyst / Nurul Zayana Yahya

Reactive blends of poly(ε-caprolactone) (PCL-diol) (semicrytalline polymer),
epoxidized natural rubber with 50 mole % epoxidation level (ENR-50)
(amorphous polymer) and toluene-4-sulfonic (pTSA) (as the catalyst) were
studied. Neat PCL-diol, neat ENR-50 and PCL-diol/ENR-50 50/50 blends doped
with different concentrations of pTSA were prepared using solvent casting
method. Homogenous distribution of pTSA in the samples is confirmed by the
visual inspection. Chemical structures for neat polymers and the blends doped
with pTSA do not change as compared to that of the undoped samples after
fourier transform infra red (FTIR) analysis at room temperature. Weight average
molecular weight (Mw) of doped-PCL-diol remains around 3500 g mol-1 while Mw
of doped-ENR-50 decreases slightly at higher concentrations of pTSA after gel
permeation chromatoghraphy (GPC) analysis. Co-continuous structure of
undoped-PCL-diol/ENR-50 50/50 blend and the dispersion of PCL-diol in the
matrix of ENR-50 for the doped-blend suggest the immiscibility of the two neat
polymers by using polarizing optical microscopic (POM). Glass transition
temperature (Tg) analysis confirmes the immiscibility of the neat constituents
where two Tgs that corresponds to the neat polymers for the doped and undoped-
50/50 blends are observed by differential scanning calorimetry (DSC) analysis.
Under non-isothermal heating up to 200 ºC, the melt reaction takes place and the
reaction temperature (Trxn) for PCL-diol/ENR-50 50/50 blends doped with pTSA
decreases at higher concentration of pTSA.