Surface treatments thermoplastic elastomers

Chem. Descrip. Reactive epoxy-functional siloxane oligomer in water Uses Adhesion promoter between inorg. materials (glass, minerals, metals) and org. polymers (thermosets, thermoplastics, elastomers) surface treatment aid for mins. reinforcement aid for glass fibers primer for glass and metals surface modifier for org. materials additive for water-borne polymers... 

Fibers of high moduli of elasticity are used to make thermoplasts and elastomers more rigid. Since the moduli of elasticity of typical textile fibers are only about 4-40 GPa, glass, steel, and carbon fibers, whose values can reach 350 GPa (Table 38-4), have been used for this purpose in the past. The poor adhesion of these fibers to thermoplasts and elastomers can be improved to various extents by surface treatment of the fibers with binding aids. 

Thermoplastic elastomers can be quite difficult to adhesively bond (Table 4.11) and invariably a primer or some other form of surface treatment (see Section 6.3) is necessary. 

A common application for adhesives is where co-axial (cylindrical parts) require to be joined. Figure 5.11 shows a typical application where the black polypropylene spigot is to be bonded and sealed into the red elastomeric (thermoplastic elastomers) housing. In this case, both these plastics are low-surface-energy materials and so will require either a surface primer or some form of surface treatment to increase the surface wetting (see Chapter 6). In this application a medium viscosity ethyl cyanoacrylate with a primer was selected. 

This chapter has been adapted from Surface Preparation of Thermoplastics, Thermosets, and Elastomers in Surface Treatment of Materials for Adhesion Bonding, S. Ebnesajjad C.F. Ebnesajjad 2006 Elsevier Inc. 

Thermoplastics, thermosets, and elastomers require surface treatment to remove contamination and prepare their surfaces for adhesion bonding. Both initial bond strength and bond durability are affected by the surface preparation technique. Most materials require unique methods of treatment for optimal bond strength formation. Most surface preparation treatment methods use or generate chemicals that have various serious health effects and must be used with extreme caution. 

The book consists of four parts. Part I contains two introductory chapters that describe the fundamental concepts of surface treatment and adhesion. Part II is comprised of chapters that describe surface tension (energy) concepts, surface characterization techniques, and surface preparation methods for metals and thermoplastics, thermosets, and elastomers. 

While organo-silane treatments are extensively used in both thermoset and elastomer applications, their use in thermoplastics has so far been somewhat restricted. This is because they do not react with the surface of calcium carbonate, one of the principal fillers used in this type of polymer and because of the lack of a suitable reactive functionality for most of the thermoplastic polymers. Today they are principally used in conjunction with glass fibres, calcined clays, aluminium and magnesium hydroxides, micas and wollastonite. The main thermo-... 

---