We present a basic principle and good practices of the rheology of polymers, particularly for teachers or lecturers at colleges or universities for educational purposes, as well as for beginner researchers who may refer to this article as their self-learning resources. Basic consideration of the experimental methods using parallel-plate oscillatory rheometer and step-by-step guidelines for the estimation of the power law dependence of storage, G′ and loss, G″ modulus as well as the estimation of the relaxation time at f    cross   G ′ − G ′′ ${f}_{\,\mathrm{cross}}^{\,{G}^{\prime }-{G}^{\prime \prime }}$ at terminal zone using various approaches such as commercial graphical software, manual graphical approach and commercial rheometer software are highlighted. Good practices for data interpretation using different approaches are described and compared where the outcomes revealed the manual graphical approach or commercial graphical software yield comparable results with the commercial rheometer software. In order to have better insight, several examples and exercises which are applicable for teaching and self-learning activities are also provided.

Thin films of poly (ethylene oxide) (PEO), poly (methyl methacrylate) (PMMA) and selected blends of PEO/PMMA with and without the addition of LiClO4 were prepared using solution casting technique. The presence of a single Tg which corresponds closely to that of the Gordon Taylor equation confirms the miscibility of both the salt-free and salt-doped blends. The Tgs and the ion conductivity (σ) at room temperature of PEO, PMMA and the PEO/PMMA blends generally increase with ascending salt concentration (Y). Variations in the σ value as a function of Y for all the three systems correlate closely with their respective Tg results. PMMA-salt complex records the lowest σ value at all salt concentrations. PEO/PMMA/LiClO4 blend with 75 wt% PEO exhibits the highest σ value of 5 x 10-7 S cm-1 at Y = 0.10. The σ value of the blend-salt system is observed to be slightly lower than that of the PEO-salt system. This is due to reduced segmental motion cause by increased Tg of the blend and a decrease in free ions in the amorphous phase of PEO as a small amount of the salt is solvated by PMMA in the blend. Therefore, the percolation path lies in the amorphous PEO rich phase of the blend.

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The influence of morphology on the rheological properties of poly(ethylene oxide) (PEO) and natural rubber-graft-poly(methyl methacrylate) (NR-g-PMMA) blends in the melt was investigated. The blends were prepared at different blend compositions by a solution-casting method. Linear viscoelastic shear oscillations measurements were performed in order to determine the elastic and viscous properties of the blends in the melt. The rheological results suggested that the blending of the two constituents reduced the elasticity and viscosity of the blends. The addition of an even small amount of NR-g-PMMA to PEO changed the liquid-like behavior of PEO to more solid-like behavior. Morphological investigations were carried out by optical microscopy to establish the relationship between morphology and melt viscosity. Depending on the blend compositions and viscosities, either droplet–matrix or co-continuous morphologies was observed. PEO/NR-g-PMMA blends exhibited a broad co-continuity range, and phase inversion was suggested to occur at the PEO/NR-g-PMMA blend with a mass ratio of 60/40 (m/m), when NR-g-PMMA was added to PEO as a matrix.

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.