Intermediate modulus

IM = intermediate modulus and UHMW PE = ultrahigh molecular weight polyethylene. 

The mechanism of chemical adhesion is probably best studied and demonstrated by the use of silanes as adhesion promoters. However, it must be emphasized that the formation of chemical bonds may not be the sole mechanism leading to adhesion. Details of the chemical bonding theory along with other more complex theories that particularly apply to silanes have been reviewed [48,63]. These are the Deformable Layer Hypothesis where the interfacial region allows stress relaxation to occur, the Restrained Layer Hypothesis in which an interphase of intermediate modulus is required for stress transfer, the Reversible Hydrolytic Bonding mechanism which combines the chemical bonding concept with stress relaxation through reversible hydrolysis and condensation reactions. 

Fig. 3 The natural logarithm of the average filament strength (n=40) as a function of the natural logarithm of the test length for an intermediate-modulus, PAN-based carbon fibre with an impregnated bundle strength of 5.7 GPa [8]...

Intermediate modulus (IM) fibers, 26 759 Intermediate neglect of differential overlap (INDO) technique, 16 737 Intermediates. See also Chemical intermediates... 

Property High strength (HS, Type If) Intermediate modulus (IM, Type II) High modulus (HM. Type III)... 

Formulated primers. The use of formulated primers in which a silane (or silanes) is blended with a film former, a solvent, and perhaps a hydrolysis catalyst, has been described by Plueddemann [16] and in the Dow Corning trade literature [17]. Primers of this type which contain a film former should not be confused with the previously mentioned silane pretreatment primers, as they deposit a film of measureable thickness and strength. Such formulated primers are required to wet the substrate, be readily wet by the adhesive or coating and should provide a layer of intermediate modulus between substrate and resin system. As with the pretreatment primers a formulated primer can be tailored to both the substrate and the resin. Ageing of formulated primers may be a problem both in the storage container and on the substrate before subsequent coating. 

Table VI contains the general properties for 50-60% HARD SEGMENT polymers. This table contains polymers which have been developed in the past such as the Polyurethanes in the 55 to 65 Shore D hardness (Fascia materials), as well as Poly(urea-urethanes) which are more recent developments. This hard segment range also covers 65 to 75D intermediate modulus materials which are in reality toughened plastics. The raw materials prices are for comparison purposes.

Table 7 Typical laminate properties on intermediate modulus carbon fiber at a fiber volume of ca. 60%...

Figure 6.4 High, low, and intermediate-modulus curves as a function of temperature. ...

Property Adhesive A (high modulus) Adhesive B (high modulus) Adhesive C (intermediate modulus) Adhesive D (low modulus) ... 

In effect, this theory postulates a chemical reaction between promoter, polymer, and mineral substrate as in the chemical bond theory but also suggests that the presence of a region of intermediate modulus between polymer and substrate which transfers stress from the high modulus surface to the relatively low modulus polymer. Adhesive technology has long recognized this principle in specially formulated primers for use when bonding rubbery polymers to metals. 

ICBM intercontinental ballistic missile IM intermediate modulus... 

A controUed-flow, tough BMI system (for intermediate modulus fibers) for prepreg uses... 

Tensile strength (MPa) Elongation at break (%) Intermediate Modulus (IM) (GPa) Tensile strength (MPa) Elongation at break (%) (IM) (GPa)... 

---