Joint filling compositions

It was mentioned above that the simulation method of Termonia [67-72] can be used to calculate the stress-strain curves of many fiber-reinforced or particulate-filled composites up to fracture, including the effects of fiber-matrix adhesion. Such systems are morphologically far more complex than adhesive joints. Many matrix-filler interfaces are dispersed throughout a composite specimen, while an adhesive joint has only the two interfaces (between each of the bottom and top metal plates and the glue layer). If one considers also the fact that there will often he a distribution of filler-matrix interface strengths in a composite, it can be seen that the failure mechanism can become quite complex. It may even involve a complex superposition of adhesive failure at some filler-matrix interfaces and cohesive failure in the bulk of the matrix. 

Adhesion at the interface of the polymer-solid is a determining factor for the physical and mechanical properties of polymer composites. Many properties of particulate-filled composites are determined by the adhesion level at the filler-matrix interface. The problems involved in adhesion are very complicated and adhesion cannot be described by any single theory [1]. Many properties of particulate-filled composites are determined by the adhesion level at the filler-matrix interface [2]. However, no theory allows calculation of the adhesion strength of joints from the data on the nature of substrate and polymer or reliable calculation of the energy of the adhesive interaction. The reason for it is the number of factors that influence adhesion [3-9]. 

Construction Materials. Superabsorbent polsrmers are used to control liquid water in a variety of construction-related products. Joint-sealing composites are made by blending superabsorbents into chloroprene rubber (54) or into poly(ethylene-co-vinyl acetate) (55). These composites are used like mortar in the concrete block walls of the structure. Gaps left during construction are subsequently filled as the superabsorbent swells in any water, and subsequent leaks are prevented. A water-blocking construction backfill has also been developed from cement, water absorbing polymer, and an asphalt emulsion (56). 

The most commonly used type of inhibited films is produced by joint processing of thermoplastic polymers and highly dispersed Cl powders. When the melting points, as well as the sublimation and thermal destruction temperatures, of the Cl exceed the viscous flow temperature of the thermoplast, the film acquires the structure of a polymer composite filled with solid inhibitor particles [101]. The particles may partially dissolve in the polymer melt and exert a plasticizing effect on the polymer. Introduction of 1-2% of NBA into PE elevates melt flow by 1.5-1.8 times [10]. Aggregation of solid Cl particles may present essential difficulties for their joint processing with polymer melts and result in structural defects or impair the quality of the film as a whole [4]. 

Adhesive joints are not, however, the only applications of adhesion. Adhesion is involved whenever solids are brought into contact, as in coatings, paints, and varnishes multilayered sandwiches polymer blends filled polymers and composite materials. Since the final performance of these multicomponent materials depends significantly on the quality of the interface that is formed between the solids, it is understandable that a better knowledge of the adhesion phenomenon is required for practical applications. 

The use of filling cracks with epoxy mass or with hard flexible polymer is also effective in the same case. Especially, repair of the cracked cement-polymer composites with addition of SBR is effective, because restores properties of floor concrete and also of the repair covering system. Unfortunately, both previously mentioned repair methods are inadequate in cases of large deformations, because of low value of the ultimate strain angle (y < 0.5 %). Overcome of this value causes appearing of new damage in concrete, close to the repair joint. 

Underwater functional joints are filled with UTK-M composition and if the joint width varies considerably, polyester cloth impregnated with UTK-M is glued on. 

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