Nanocomposites based on thermoplastic polyurethane, millable polyurethane, and organoclay: effect of organoclay content

Abstract

Dynamically vulcanized thermoplastic polyurethane/millable polyurethane blend and its organoclay-based nanocomposites with co-agent assisted peroxide curative system were prepared by melt intercalation technique using batch mixer followed by compression molding to make sheets. Fourier transform infrared spectroscopy analysis revealed the presence of interfacial interactions due to hydrogen bonding of PUs with organoclays. X-ray diffraction and transmission electron microscopy analyses qualitatively established the uniform dispersion of organoclays within the PU matrix up to 5 phr Cloisite 30B (C30B) content and exhibited small aggregates at higher C30B loading. Mechanical testing reported significant improvement in tensile strength with addition of C30B up to 5 phr loading and then reduced a little but tensile modulus continuously increased with increase in C30B loading. Dynamic mechanical analysis (DMA) evaluated that the storage modulus (E 0 ) and glass transition temperature (T g ) of both hard and soft segments of PU matrix substantially enhanced by incorporation of C30B. Thermogravimetric analysis revealed that the thermal stability of the PU matrix noticeably increased with C30B loading. Melt rheological characterization reported that all samples showed a strong shear thinning behavior within the scanned frequency range.

Understanding the mechanical and interfacial properties of core–shell structured bamboo–plastic composites

“…A similar observation was reported by Lin et al . and Barick and Chang . The highest value of the dynamic modulus was achieved for CSHDPE compared to those of CSBPF and CSWM.…”

Effect of OMMT reinforcement on morphology and rheology properties of polyurethane copolymer nanocomposites

“…Thermal degradation occurs in three or two stages with respect to hard and soft segments microdomains degradation. 28,36 TGA curves illustrate a mass loss of neat PUC/75 and its nanocomposites against temperature range from 0 C to 700 C. The onset temperature (T onset ) of neat PUC/75 was recorded around 300 C. All PUC/ OMMT nanocomposites samples display a good improvement in T onset compared to that of neat PUC/75. This reveals an increase in thermal stability of PUC/OMMT nanocomposites due to the presence of OMMT nanofillers in comparison with neat PUC/75.…”

“…Therefore, the domination of the viscosity behaviour of PUC/OMMT nanocomposites was found to be less similar to a relaxation response exhibiting actual shearthinning behaviour especially at higher frequency. 28,29,49 As compared with the neat PUC/75, a noticeable variation in the G 0 values is observed for PUC/OMMT samples at the whole frequency scope, which indicates the transition from liquid-like to solid-like viscoelastic response. As shown in Figure 9(a), neat PUC/75 melt is found to have not withstood shear at the range of frequency.…”

“…24 Investigations of the MMT incorporated with PUCs nanocomposites have interested many researchers due to the formation of new structural networks between conventional MMT fillers and PUCs matrices. 12,[25][26][27][28] The fundamental need is to modify the MMT structure by using OMMT to be more effective on transferring load from PUC chains to OMMT nanofillers. Most of the previous studies focused on the melt viscosity behaviour, which is undoubtedly affected by filler dispersion quality degree.…”

The effect of OMMT reinforcement and annealing treatment on mechanical and thermal properties of Polyurethane Copolymer nanocomposites

“…53 Hence, the value of tan δ is defined as the ratio between the loss and storage modulus (E''E') and thus tanδ peaks can represent the T g values . 59

Figure 2.Semi-log DMTA storage moduli and tanδ versus temperature data for PUC with PU/OMMT nanocomposites (A): non-annealed; (B): annealed at 80 o C for 4 days).

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