Thermal Properties and Morphology of Compatible Poly(ethylene oxide)/Natural Rubber‐graft‐poly(methyl methacrylate) Blends

Abstract

Free standing films of blends of poly(ethylene oxide) and natural rubber‐graft‐poly(methyl methacrylate) (PEO/NR‐g‐PMMA) with 40 mol% of PMMA‐graft were prepared at different mass compositions using solution casting technique. These blends show immiscibility in the molten state as indicated by two glass transition temperatures (Tg's), which correspond relatively close to the PEO and NR‐backbone components. The assessment of Tg of the PMMA‐graft can not be made under the experimental condition (heating up to 80 °C). It is expected that the Tg of PMMA‐graft is around 100 °C. Upon cooling from the melt, PEO crystallizes and liquid‐solid phase separation takes place. At room temperature, although the blends are immiscible, results show that the amorphous phase of the blends may comprise of mixture of compatible interfacial region of PEO and PMMA‐graft. Differential scanning calorimetry (DSC) analysis was used for the qualitative assessment of the blend compatibility. The compatibility of PEO and PMMA‐graft was evaluated by change in heat capacity (ΔCp) of the glass transition of PEO and NR‐backbone in the blends. Furthermore, the crystallinity (X*) and melting temperature (Tm) of PEO in the blends at higher content of NR‐g‐PMMA are depressed, which support the Tg and ΔCp results. These findings are in agreement with PEO crystalline structure from WAXS analysis and morphological studies where the PEO spherulites show a significant change upon addition of NR‐g‐PMMA in the blends.

Melt Rheological Behavior and Morphology of Poly(ethylene oxide)/Natural Rubber-graft-Poly(methyl methacrylate) Blends

“…The properties of ternary systems of PEO/NR-g-PMMA with the addition of inorganic salt will be discussed in a forthcoming publication. The thermal properties and the morphologies at 25 • C of these binary blends were reported in [38,39].…”

The Effect of Blending Natural Rubber‐graft‐poly(methyl methacrylate) on the Dielectric Relaxation of Poly(ethylene oxide)

“…The integrated peak areas of the NMR spectra as shown in Figure were used to calculate the mol% of grafted PMMA content on NR‐ backbones as reported elsewhere. [ 52 ] The characteristics of NR‐ g ‐PMMA and the analysis are shown in Table S1 in the Supporting Information. As a result, the grafted PMMA content is 40 mol% and the number averaged molecular weight of the PMMA‐ graft is 3100 g mol −1 .…”

“…The characteristics of purified PEO and NR-g-PMMA used in this work were tabulated in Table 1, which was published in references. [29,52] For the blends' preparation, solution casting technique was used to prepare free standing PEO/NR-g-PMMA films. These films were prepared from 2% (m/m) (m denotes mass) solutions of two polymers in tetrahydrofuran (THF) (Merck, Darmstadt, Germany).…”

Thermal analysis: basic concept of differential scanning calorimetry and thermogravimetry for beginners

“…The derivative curve obtained from a single step decomposition process is displayed in Figure 13. Example of TGA analysis where T d, inflection and the temperature onset beginning of mass loss (T d, onset ) for poly(ethylene oxide)/natural rubber-graft-poly(methyl methacrylate) (PEO/NR-g-PMMA) binary blends (Zainal, Chan, & Ali, 2017) are listed in Table 2.…”

“…(5). Data is retrieved from (Zainal et al, 2017). Table 3 lists the E a quantities for different systems estimated using the Hoffman's Arrhenius-like relationship, retrieved from (Halim, Chan, & Sim, 2016;Zainal et al, 2017).…”