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ArticlesFeaturedThermoplastic Elastomers & Urethanes

Fumed silica benefits mechanical properties of TPU prepared by in situ polymerization

Fumed silica is widely used as a reinforcement additive in silicone elastomers with significant mechanical property benefits, namely increased tensile strength, elongation and tear strength, among others. However, the use of fumed silica in thermoplastics is limited because of the difficulty to effectively add them via melt compounding by an extruder. Fumed silicas are extremely light; they have a bulk density of about 50 to 100 g/l. Thus, feeding this low density powder into the extruder, as well as conveying and mixing it with a viscous polymer melt, presents a challenge in typical plastics compounding operations.

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ArticlesFeaturedThermoplastic Elastomers & Urethanes

Software based tape stacking with the aid of camera technology paves the way for thermoplastic composites

Thermoplastic tapes are expected to achieve great things, namely to shape the next generation of thermoplastic composites. This calls for highly accurate tape stacking. At the same time, tape processing must not become so complex that it becomes uneconomical. Engel contributes this technology to achieve a breakthrough by combining high precision control software with camera technology in tape stacking.

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ArticlesFeaturedTire Technology & Manufacturing

Functionalized liquid rubber for tire formulations

Plasticizers are one of the key components of the rubber and adhesives industries. Plasticizers are used to lower hardness, improve processability and reduce raw material costs. On the other hand, mechanical properties deteriorate with plasticizer content. In addition, plasticizers often cause changes in properties with time and staining due to volatilization or bleeding. Phthalate plasticizers and aromatic oils are or possibly will be regulated due to environmental and human health issues. Kuraray liquid rubbers (KLR) are plasticizers which are co-vulcanizable with solid rubbers. Therefore, it is very unlikely that KLR will be subject to these bleeding or volatilization issues. As a result, KLR is expected to have a growth potential as an environmentally friendly plasticizer.

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ArticlesChemicals & MaterialsFeatured

Processing promoters: Additives for rubber compounds improve mixing and processing

The efficient mixing of rubber compounds comes with many challenges. These include effectively blending the individual raw materials, which involves breaking down and blending different types of elastomers, adequately dispersing large fractions of fillers, oils and small weighments of chemicals in a relatively short time in the internal mixer. Once mixed, the compound then must be processed, e.g., extruded, calendered or molded to form the desired shape which is then vulcanized to produce the final product. The choice of the correct processing promotor will assist in these efforts. Certain promotors function primarily as dispersing agents, whereas others act more as lubricants to speed the mixed compound through the production process. Both types improve overall compound quality and production efficiency. Compound viscosity typically is also reduced. This article will focus on a number of processing promotors offered by Rhein Chemie and their effects on rubber compound quality and processability.

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ArticlesChemicals & MaterialsFeatured

FKM and FFKM crosslinking methods and their effect on upper use temperature of seals

Fluoroelastomers (FKMs) were first introduced to market more than 50 years ago in response to performance needs in the aerospace industry. Their increased thermal stability and chemical resistance, and comparable mechanical properties relative to hydrocarbon rubber materials provided significant performance benefits. Not surprisingly, FKM compounds soon became widely adopted in seals and gaskets for many other applications across the automotive, oil and gas, semiconductor and pharmaceutical/ food processing industries, where long term durability and reliability in challenging environments was critical.

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ArticlesChemicals & MaterialsFeatured

Dynamic mechanical properties and crosslink density testing of silicone elastomers

Material evaluation tests for this article were performed using the recently developed Dynamic Mechanical Yerzley Oscillograph (DMYO). Just like the Yerzley Oscillograph (YO), the DMYO supports the ASTM D945 standard. Its design is an evolution of the YO with additional sensors,
electronic data acquisition and computer control, including automated data evaluation.

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