Shrinkage adhesive test

Figure 14.5. Various film adhesion tests (a) wedging, (b) lap test, (c) shrinkage, (d) blister,...

PSA Formulation and Properties. The formulations used in this study for the Hycar 2103-Prepolymer C and Hycar 2106-Prepolymer C PSA contain OH/NCO ratios of 1.7 and 1.3, respectively. Dibutyltin dilaurate catalyst is used at a 0.2 wt.% level based on the total adhesive solids. PSA samples are made from an 80% solids solution (by wt.) with a dry solvent system (27/73 by wt. of ethyl acetate-toluene) and cured at 150°C for 45 seconds. The samples are then evaluated by running 180° peel, static shear, rolling ball tack, and vinyl film shrinkage tests. 

These adhesive systems give an excellent combination of static shear (at both room temperature and 70°C) and rolling ball tack along with excellent vinyl film shrinkage resistance. The results of these tests are summarized in Table III. 

Figure 9 Overview of fracture surface of phenol-formaldehyde bonded joint showing exposed adhesive layer (A) without preexisting cure-shrinkage cracks and surface of lower adherend (B). The sloped test fracture surfaces (arrow) characteristic of phenol-formaldehyde and toughened urea-formaldehyde adhesive layers show where the crack jumped from one interphase to the opposite as the crack traveled in the fiber direction.

EN 302-4 2004, Adhesives for load bearing structures — Test methods — Part 4 Determination of the effect of wood shrinkage on the shear strength. 

Modifications of the surface properties ofman-made fibers play a dominant role in several end-uses. Via a variety of application processes it is possible to treat manmade fibers with fluorine gas. The electronegativity of flouorine is 4.0eV the highest of all elements. In particular, the siuface activity of yams can be increased considerably by incorporating fluorine atoms. As part of this investigation some polymers and fiber types for diverse end-uses were tested (Table 17.1). All end-use applications for these yams have important surface function requirements, e.g., for tire yams the adhesion to mbber is very important while for tarpaulins it is the adhesion to PVC. Textile and medical applications with different end-use characteristics were also considered. The modifications attempted to this investigations did not influence other properties such as tenacity, elongation, or shrinkage. 

The polymer mortars with SF were tested by Ohama et al. (1989) in view of their application for industrial floors, decorative coatings and repair of concrete structures. The results were interesting and have shown different influence of SF, that is, an increase of compressive strength and resistance to water permeation and penetration of chloride ions, but no improvements have been observed of resistance to water absorption, carbonation and drying shrinkage. Also, adhesion of the composite to covered concrete surfaces was not increased. 

Test for adhesion and cohesion of elastomeric joint sealants under cyclic movement Test for extrudability after package aging of latex sealing compounds Test for aging effects of artificial weathering on latex sealing compounds Test for volume shrinkage of latex sealant compounds... 

Cationic curing provides improved adhesion on all tested polyolefins, without the need for a corona treatment Corona treatment is necessary for free radical formulations but is not very effective for increasing adhesive property. The lower shrinkage and the formation of hydroxyl groups in cationic curing are the factors which ensure the improved adhesive property. 

Inspection tests before shipments of adhesive products are as follows adhesion strength, tackiness, hardness, viscosity, density, volume shrinkage, thermal expansion, shelf life, pot life, gelation time, water resistance, chemical resistance, weather resistance, flame retardance, electric conductivity, color, optical properties, amount of volatile organic compounds (VOC) emergence, etc. Some of these tests are the same as those tests for acceptance. Before shipment, strength tests of joints are very important for adhesives in terms of performance proof (see Chap. 19). In contrast, for PSAs, tackiness is important (see Chap. 15). Other important properties that should he tested are shown below. 

This paper discusses the properties of polymer-modified mortars with silica fume. The polymer-modified mortars using a styrene-butadiene rubber latex and an ethylene-vinyl acetate emulsion are prepared with various polymer-cement ratios and silica fume contents, and tested for flexural and compressive strengths, adhesion, water absorption and permeation, water resistance, drying shrinkage, carbonation and chloride ion penetration. The effects of the polymer-cement ratio and silica fume content on the properties of the polymer-modified mortars are e>amined. In conclusion, the addition of the silica fume causes improvements i- the compressive strength, resistance to water permeation and chloride ion penetration. However, the adhesion, resistance to water absorption and carbonation and drying shrinkage are not improved by silica fume addition. 

---