Elastomeric gel

To achieve low stress embedding material, low modulus material such as siUcones (elastomers or gels) and polyurethanes are usually used. Soft-domain elastomeric particles are usually incorporated into the hard (high modulus) materials such as epoxies and polyimides to reduce the stress of embedding materials. With the addition of the perfect particle size, distribution, and loading of soft domain particles, low stress epoxy mol ding compounds have been developed as excellent embedding materials for electronic appHcations. 

Elastomers come next in order of quantity sold worldwide. Like the previous categories, elastomers cover an extremely broad range of material types and application areas. They include cast elastomers, spray and rotational casting elastomers, thermoplastic elastomers, microcellular elastomers, gels, and elastomeric fibers. Each type is covered separately.13d> 14... 

This polypeptide is structurally identical to ABA-type triblock copolymer with a central hydrophdic elastomeric end-block capped with two hydrophobic plastic end-blocks and exhibits amphiphilic characteristics. The end-blocks of the polymer were chosen in such a way that their LCST would reside at or near room temperature. Thus the polymer exhibits phase separation, which is analogue to conventional TPEs, and offers TPE gels under physiological relevant conditions [104]. Glutamic acid residue is placed periodically in the elastomeric mid-block to increase its affinity towards the aqueous... 

Six transition points in all were defined by Greenhoe which, with rising temperatures, were fluid point dry point gel point haze point elastomeric point and fusion point. 

Cured Consistency. The hardness of these gels can not be measured by the normal methods used for elastomeric materials. Test methods for characterizing their physical properties are in various stages of development. The most commonly used technique to describe the gel s softness is the penetration test, which is emerging as a... 

Variation of structural and compositional parameters allow modification of the physical properties to tailor performance to specific application needs. For example, the effect of ingredients added to control the modulus of two UV curable silicone polymers is presented in Figure 1. Both Polymer A and Polymer B were polydiorganosiloxanes which contained terminal reactive unsaturation. Admixture with a photosensitization system and subsequent cure afforded soft, elastomeric products. Modifier A was incorporated into Polymer A to soften the system further. As the concentration of Modifier A increased, the modulus decreased, and the resultant composition became more gel-like. In a contrary fashion, Modifier C was added to Polymer B to provide reinforcement. As the concentration of Modifier C was increased, the modulus of the resultant cured film increased, the elongation decreased, and the tensile strength went through a maximum. 

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