Polymer Library

Silicone Elastomers - September 2016

This month's topic focus is silicone elastomers. The market for silicone elastomers may be relatively small but it is globally significant. The industry as a whole is expected to increase by 6% according to recent Smithers Rapra research. The largest end use sector is transportation, with other applications - electric/electronic, medical and healthcare and consumer sectors - also performing well. There are also emerging markets for silicone elastomers in more demanding applications, such as the exploration and production of oil and gas. The superior properties of silicone elastomers, including wide ranging temperature stability, biocompatibility, inertness, low flammability and durability, as well as low processing costs, will continue to drive demand across all end-use applications.

Why not review some of the items we've added to the Polymer Library about silicone elastomers?

Abstracts

These abstracts were highlighted in the September Newsletter and found in the Polymer Library.

Click on the 7-digit accession numbers to find out about ordering a copyright-cleared full text copy of the items shown.

1227637 - Green silicone elastomer obtained from a counterintuitively stable mixture of glycerol and PDMS
A green and cheap silicone-based elastomer has been developed. Through the simple mixing-in of biodiesel-originating glycerol into commercially available polydimethylsiloxane (PDMS) pre-polymer, a glycerol-in-PDMS emulsion was produced. This counterintuitively stable mixture became a basis for obtaining elastomeric composites with uniformly distributed glycerol droplets. Various compositions, containing from 0 to 140 parts of glycerol per 100 parts of PDMS by weight, were prepared and investigated in terms of ATR-FTIR, broadband dielectric spectroscopy, mechanical properties as well as optical and scanning electron microscopy. The materials were proven additionally to exhibit a strong affinity to water, which was investigated by simple water absorption tests. Incorporating glycerol into PDMS decreased the Young's modulus of the composites yet the ultimate strain of the elastomer was not compromised, even in the presence of very high loadings. The conducted experiments highlight the great potential of this new type of elastomer and reveal some possible applications. (28 ref)
Polymer, Citation: 87, No.1, 2016, p.1-7, DOI: 10.1016/j.polymer.2016.01.070
Mazurek P; Hvilsted S; Skov A L

1232989 - Inorganic fillers influence on the radiation-induced ageing of a space-used silicone elastomer
A space-used filled silicone rubber (silica and iron oxide fillers) and its polysiloxane isolated matrix were exposed to high energy electrons in order to determine their ageing mechanisms from a structural point of view. Physicochemical analysis evidenced that both filled and unfilled materials predominantly crosslink under such irradiation. Solid-state 29Si NMR spectroscopy allowed the identification of T-type SiO3 units as the main new crosslinks formed in the polymer network. It also revealed an increase in Q-type SiO4 units in the irradiated filled sample. Thanks to the combination of NMR spectroscopy and ammonia-modified swelling tests, these Q-type units were associated with new crosslinks formed at the silica fillers-matrix interface. While the main interaction between the polysiloxane network and the fillers was shown to proceed mainly through hydrogen bonding in the pristine filled samples, it was suggested that the hydrogen bonds were progressively replaced with SiO4 chemical bonds. These additional chemical crosslinks induced evolutions of the shear modulus on the rubber plateau and crosslink density that were significantly more pronounced in the filled material than in the neat one. (10 fig, 1 tab, 40 ref)
Polymer Degradation and Stability, Citation: 128, June 2016, p.126-133, DOI: 10.1016/j.polymdegradstab.2016.03.010
Roggero A; Dantras E; Paulmier T; Tonon C; Dagras S; Lewandowski S; Payan D

1234479 - UVA-shielding silicone/zinc oxide nanocomposite coating for automobile windows
Among all types of ultraviolet radiation, UVA rays are the most prevalent and can penetrate clouds and glass. In this article, we report the fabrication of a novel silicone/zinc oxide (ZnO) nanocomposite that has outstanding performance in shielding the harmful UVA light. We prepared wurtzite ZnO nanoparticles of three growth durations and dispersed them in a transparent silicone matrix via solution mixing. Our results exhibit a red shift in the absorption peak of the nanocomposites when compared with ZnO colloidal dispersions and decreasing the growth duration of ZnO nanoparticles could improve the UVA-shielding properties of the nanocomposite. In addition, the nanocomposite presents good shear adhesion strength over 10.5 MPa on glass substrate. The excellent optical and mechanical properties of the novel nanocomposite make it highly promising for automobile window coatings. (20 ref)
Polymer Composites, Citation: 37, No.7, 2016, p.2053-2057, DOI: 10.1002/pc.23383
Xueying Zhao; Liyi Li; Yan Liu; Ching-Ping Wong

1236950 - Molded silicone parts from the printer
Wacker in conjunction with Enders Ingenieure GmbH has developed a process for creating objects out of silicone rubber via 3D printing. The silicone rubber exhibits an exact degree of viscosity and can be extruded in small liquid drops, which quickly solidify into a layer and are then vulcanised with UV light. A specially constructed 3D printer with a movable nozzle is used to create moulded parts layer by layer from lots of the silicone drops. Possible applications range from prototypes to customised products, small series in automobile manufacturing, medical technology and household products.
Wacker World Wide, Citation: 15, No.2, 2015, p.66
Wacker; Enders Ingenieure GmbH

1233767 - Crystal clear specialty silicones for optical components
The development of a highly transparent liquid silicone elastomer, called Lumisil LR 7600, specifically for the manufacture of optical lenses and light coupling components is reported. This new elastomer constitutes a high-quality alternative to conventional optical materials, such as glass, polycarbonate and PMMA, and opens up new possibilities for the lighting industry.
Rubber World, Citation: 254, No.1, Apr. 2016, p.49-50
Rouse J

1236726 - Wrinkled elastomers for the highly stretchable electrodes with excellent fatigue resistances
For the development of highly stretchable electrodes with excellent fatigue resistance, wrinkled elastomers were newly prepared as elastomeric substrates by applying the interpenetrating polymer network (IPN) concept of silicone rubber (SR) and acrylic rubber (AR). On releasing the pre-stretched IPN substrates, which were spray-coated with single-wall carbon nanotubes (SWNT) or multi-wall carbon nanotubes (MWNT), highly stretchable electrodes with excellent fatigue resistance were successfully fabricated. The presence of SR in the AR matrix was confirmed with water contact angle measurement and chemical structure analysis. The SR layer was automatically wrinkled on the AR surface after relaxing the cured elastomers under a certain deformation. Wavelength and amplitude of the developed wrinkles can be precisely controlled by tuning the pre-strain of the elastomeric substrate. From the morphological observations, it was found that the wrinkles were initially formed at 35% pre-strain and the wavelength decreased with increasing pre-strain. The more wrinkles on the surface, the better the electrical stability up to 140% tensile strain. The electrical conductivity ( ~ 10^2 S/cm) of the electrode was confirmed even after the 100,000 cycles of dynamic strain (33%). (40 ref)
Polymer Testing, Citation: 53, Aug. 2016, p.329-337, DOI: 10.1016/j.polymertesting.2016.06.003
Gi-Bbeum Lee; Shibulal Gopi Sathi; Dae-Yoon Kim; Kwang-Un Jeong; Changwoon Nah

1235173 - Skin-inspired hydrogel-elastomer hybrids with robust interfaces and functional microstructures (Open Access - Free PDF Available)
Inspired by mammalian skins, soft hybrids integrating the merits of elastomers and hydrogels have potential applications in diverse areas including stretchable and bio-integrated electronics, microfluidics, tissue engineering, soft robotics and biomedical devices. However, existing hydrogel-elastomer hybrids have limitations such as weak interfacial bonding, low robustness and difficulties in patterning microstructures. Here, we report a simple yet versatile method to assemble hydrogels and elastomers into hybrids with extremely robust interfaces (interfacial toughness over 1,000 Jm^-2) and functional microstructures such as microfluidic channels and electrical circuits. The proposed method is generally applicable to various types of tough hydrogels and diverse commonly used elastomers including polydimethylsiloxane Sylgard 184, polyurethane, latex, VHB and Ecoflex. We further demonstrate applications enabled by the robust and microstructured hydrogel-elastomer hybrids including anti-dehydration hydrogel-elastomer hybrids, stretchable and reactive hydrogel-elastomer microfluidics, and stretchable hydrogel circuit boards patterned on elastomer. 52 Refs.
Nature Communications, Citation: June 2016, paper 12028, pp.11, DOI: 10.1038/ncomms12028
Yuk H; Zhang T; Parada G A; Liu X; Zhao X

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COMING SOON

TPE and Silicone Elastomers World Summit 2016
30 November-1 December 2016 in Cologne, Germany
Dedicated to delivering meaningful content and connections ahead of the curve: this is the place to get the most relevant, forward-thinking, actionable information for the silicone and thermoplastic elastomers industry.
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