Dynamic rheological behavior and microcrystalline structure of dioctyl phthalate plasticized poly(vinyl chloride)

Abstract

ABSTRACT:The dynamic rheological behavior of poly(vinyl chloride) (PVC)/dioctyl phthalate (DOP) systems were studied as a function of DOP content and melting temperature. The dynamic rheological behavior of the PVC/DOP systems was found to be remarkably affected by the DOP content. The observed curves of storage modulus (G 0 ) versus frequency were well fitted to an empirical equation0 is the lowfrequency yield value of the storage modulus, the exponent n is a dependent index of frequency, K is a constant coefficient, and x is the angular frequency). The loss tangent and/or phase angle increased remarkably at a higher DOP content. There was an apparent critical DOP content transition where the dynamic rheological behavior of the PVC/DOP systems changed greatly. Scanning electron microscopy observations revealed the existence of a multiscale particle structure in the PVC/DOP systems. For the PVC/DOP (100/70) system, with increasing melting temperature, its dynamic rheological behavior showed an apparent mutation at about 190 C. Differential scanning calorimetry (DSC) analysis confirmed that the high elastic networks in the PVC/DOP systems were closely related to the microcrystalline structure of PVC. The transitions in the curves of the gelation degree and crystallinity versus the DOP content corresponded well to the DOP content transition in the dynamic rheological behavior. DOP could inhibit the secondary crystallite of PVC and almost had no effect on the primary crystallite of PVC. The coexistence of the microcrystalline structure of PVC and the plasticizer (DOP) resulted in high elastic networks in the PVC/DOP systems. The DSC results explained the DOP content transition and the temperature transition in the dynamic rheological behavior of the PVC/DOP systems well.

Rheology of Green Plasticizer/Poly(vinyl chloride) Blends via Time–Temperature Superposition

“…Examples of the original (i.e., unshifted) frequency sweeps for DEHP, DINCH, dioctyl succinate (DOS), dioctyl maleate (DOM), and 1,4-butanediol dibenzoate (1,4-BDDB) can be found in Figures S2-S11 of the supplementary materials. It can be seen that with an increasing frequency, G' and G" increased, which is consistent with previous rheological studies on plasticized PVC systems [24]. Although both curves in Figure 2 resemble each other, G" was slightly higher for the DINCH blends compared to the DEHP blends (one-way ANOVA with repeated measures and Bonferroni's multiple-comparison post-test, p < 0.0001), but the elastic modulus, G', was similar for both (not significant, p > 0.05 (ns)).…”

The effect of crystallites on the rheological properties of microphase‐separated PVC‐PBA‐PVC triblock copolymers obtained by single electron transfer‐degenerative chain transfer living radical polymerization

“…In fact, the alteration of the terminal zone provoked by either the microphase separation or the microcrystalline structure of PVC was very similar. The crystallites acted as physical crosslinking points, giving rise to slightly frequency dependent dynamic moduli and G 0 > G 00 , even at temperatures close to 200 C [32,33]. This finding is not surprising, considering that PVC particles have crystallites of varying sizes with a broad melting range, practically from 100 C to 230 C [13,14].…”

Preparation of Smart Fluid from Polymer Coated Pumice Particles

“…It is well known that the relationship between storage modulus (G') and loss modulus (G") indicates whether the material is solid-like (G' > G"), gel-like (G' ≈ G") or liquid-like (G" > G') in the whole frequency range measured [22].…”