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Two‐way shape memory polymers (SMPs) have gained significant attention in the recent past owing to their ability to spontaneously and reversibly switch between two different shapes when heated and cooled, thereby allowing them to reversibly actuate autonomously. Semicrystalline elastomers are one of the best classes to design two‐way SMPs owing to the crystallization‐induced elongation and the melting‐induced contraction that can result in reversible strain in the elastomeric network and can be applied to fabricate artificial muscles and actuators. This review revisits the overview of the SMPs and the inspiration behind developing two‐way shape memory semicrystalline elastomers and their mechanistic pathway. Finally, the latest developments in the realm of the elastomeric networks and how these smart materials are gaining spotlight along with the future purview and potential outlook are circumscribed. [ABSTRACT FROM AUTHOR]

Role of sol–gel interaction with anisotropic nanoclay in raw natural rubber (NR) for offering higher mechanical reinforcement than isotropic nano zinc oxide was reported in this article. Experiments were carried out on four different grades of NR, having equal Mooney viscosity but different gel contents (toluene insoluble fraction), with commercial grades of nanofillers. In raw NR, the green strength was found to be influenced by higher apparent viscosity instead of higher gel content. In unvulcanised nanocomposites, however, the reinforcement was subjected to interaction between the nanofillers and the sol fraction (toluene soluble fraction, major part of the matrix) of NR. The mixing energy was decreased by approximately 2.9% for nanoclay (Cloisite 30B) and 4.4% for nano zinc oxide addition, whereas the gel content has increased upon addition of Cloisite 30B and nano zinc oxide by 12% and 49%, respectively. The ability was found higher with nano zinc oxide due to its isotropic shape and lower overall size than Cloisite 30B. Conversely, higher sol concentration of Cloisite 30B along with higher filler volume fraction offered higher mechanical reinforcement in both high and low gel grades of NR. The fact was established from extensive studies on morphology, filler crystallography, gel content, and viscoelastic responses. [ABSTRACT FROM AUTHOR]

Styrene butadiene styrene (SBS) block copolymers comprise of two phases structured domains involving polystyrene "hard" domains and butadiene "soft" domains. The styreneic domains provide a physical crosslink that enables SBS to behave like a highly flexible thermoplastic elastomer. Recently, with the rise of smart elastomers, SBS‐based matrices are being extensively used in transforming them into elastomers that can exhibit shape change when excited with a range of stimuli (shape memory elastomers). With the advantages of long‐range elasticity, reprocessability, and ability to be modified into various tailor‐made shape morphing elastomers, the use SBS‐based elastomers has exceptionally risen in the scope of deployable structures temperature sensors, snap fittings, and actuators. This review attempts to tether the recent development in SBS‐based shape memory polymers along with highlighting the fabrication routes and the shape memory mechanistic pathway. The review introduces the concept of shape memory polymers, classification, and their characterization, followed by shape memory elastomers and finally one way/two‐way SBS‐based shape memory elastomers. In an attempt to blend both the scientific and the engineering realm, the narrative provides a concise overview of SBS‐based shape morphing polymers' expanding boundaries. [ABSTRACT FROM AUTHOR]

Polar monomers are often grafted onto poly(ethylene-co-octene) [POE] to expand its application spectrum. However, the process frequently involves cautious handling of reactive monomers and hazardous solvents. On the contrary, the present work deals with similar modification but using a polymer, poly(ethylene-co-vinyl acetate) [EVA] in the melt through the formation of a double network hybrid using an external crosslinker. POE is an important new generation elastomer having great balance between physical and mechanical properties but its polarity needs to be improved for furthering its uses in industrial oil resistant applications and surface adhesion with other agents. The POE (major component)-EVA (minor component) hybrid compositions were designed using Taguchi statistical technique for optimization. Physico-mechanical properties like tensile, stress relaxation, hysteresis, rheological properties like pseudoplastic index, die swell and solvent swelling kinetics were investigated. The results were found depended on the network morphology of the hybrids. One composition was finally selected which produced better balance between all physico-rheological properties. [ABSTRACT FROM AUTHOR]

This paper demonstrates interesting contrasts between physical, mechanical and rheological properties of double network hybrids developed from high (30 wt.%) and low (9 wt.%) methyl acrylate containing poly (ethylene-co-methyl acrylate) and poly (ethylene-co-octene) thermoplastic elastomer. The compositions were designed adopting a Taguchi L9 statistical model. The model was espoused to consider a wide range of blend compositions and process conditions for optimization. The majority of the low methyl acrylate containing hybrids showed normal correlation between mechanical and other physical properties with the net gel content while for the other variety, they were ambiguous. The reason was investigated and it was found to be due to the influence of the nature of crosslinks formed between the phases which controlled the properties in the latter. Based on the results, finally, two blend compositions were chosen from each set as the most optimized formulations for future study. [ABSTRACT FROM AUTHOR]

Polar modification of poly(ethylene- co-octene) (POE) elastomer was carried out with a relatively new approach. Poly(ethylene- co-acrylic acid) (EAA) was taken as the modifier and POE with a calculated amount of EAA were coextruded with dicumyl peroxide (DCP; used as a crosslinker). The majority of the compositions showed the existence of a crosslinked EAA phase inside POE, although increasing DCP concentrations and extrusion temperatures were possibly capable of crosslinking either of the phases, as observed with a model composition. All of the samples were soft and light in nature. The best composition was the one that contained 13.3 wt % EAA; that composition showed excellent surface polarity and superior mechanical properties. Detailed solvent swelling experiments also yielded the best results for that particular composition. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 [ABSTRACT FROM AUTHOR]

The article presents information on a study which described the synthesis of a new class of ionomer via the grafting of acrylic acid onto a metallocene-based poly(ethylene octene) elastomer, then by neutralization with zinc acetate. A review of the related literature is given. The characterization of the ionomeric product was done through Fourier transform infrared spectroscopy, small-angle X-ray scattering and transmission electron microscopy. The effect of the ionomerization is described.

A new class of ionomer was developed through sulfonation of the metallocene-based poly(ethylene–octene) elastomer, followed by its neutralization with zinc acetate. Ionomeric products were characterized through Fourier transform infrared (FT-IR) spectroscopy, small angle X-ray scattering (SAXS), and transmission electron microscopy (TEM) studies. The effect of pendant chain length on the ionomeric modification was also studied through the variation of the comonomer. The impact of these ionomeric modifications on various physico-mechanical properties was thoroughly investigated by using differential scanning calorimetry, mechanical, dynamic mechanical, and thermogravimetric analysis. The resultant properties were correlated with structures of the modified elastomers. Ionomerisation of the base elastomers causes a significant improvement in the stress–strain, as well as the thermal properties compared to the corresponding pristine elastomer. [ABSTRACT FROM AUTHOR]

This paper introduces a poly(ethylene- co -octene)-poly(ethylene- co -vinyl acetate) double network hybrid as a noble additive cum compatibilizer for poly(ethylene- co -octene) (POE). The addition of only 0.5 mass% of the hybrid into POE has raised the net crystallinity from 29% to 59% and consequently improved both static (tensile strength, modulus and elongation at break) and dynamic (stress relaxation and hysteresis) properties of the virgin POE. As compatibilizer for organically modified montmorillonite (OMt) most of the properties further improved at a minimal loading of both OMt (0.5–1.0 mass%) and compatibilizer (1–2 mass%) owing to the establishment of a dominant intercalated structure. Although the die swell is slightly increased in the presence of both double network hybrid and OMt, the extruded profiles exhibit remarkable improvement in appearance compared to the virgin POE. [ABSTRACT FROM AUTHOR]