Bond Strength Development Research Articles

Bond strength development between latex-modified cement paste and steel

Bond strength development between latex-modified cement paste and steel was determined using a new technique, the overhanging beam method. Six latexes were studied. In general bond strength is improved with latex addition. Factors affecting bond strength include non-evaporable water content, heat of hydration, and CH content. The role of the interface zone on bond strength has been evaluated.

A novel technique for determining bond strength development between cement paste and steel

A new technique for determining bond strength between cement paste and steel is described. Internal stess resulting from the hydration process is taken into account. Experimental results of bond strength development are presented. The role of the interface zone in determining bond strength is discussed with reference to information provided by SEM examination of debonded surfaces.

Surface, interfacial and molecular aspects of polymer bioadhesion on soft tissues

Interfacial phenomena related to the adhesive properties of synthetic polymers, hydrocolloids and related systems in contact with soft, natural tissues are discussed. The nature of the adhesive interface, the surface roughness, the chemical structure of the bioadhesive-candidate material, the swelling (hydration) at the adhesive interface, and the dynamic development of the bioadhesive bond strength are analyzed in terms of molecular and surface theories. Available in vitro testing techniques for bioadhesion provide an indication of the efficiency of proposed polymers as bioadhesives. These theoretical analyses and experimental results are used to establish general guidelines for the development of bioadhesive controlled release systems of bioactive agents for buccal, nasal, gastric, intestinal, urinary and rectal uses.

Bond strength between C 3S paste and iron, copper or zinc wire and microstructure of interface

Bond strength between C 3S paste and iron, copper or zinc wire and microstructure of the interfacial region were examined by pull-out test and scanning electron microscope respectively. The bond strength between C 3S paste and iron wire at 28-day curing is larger than that between C 3S paste and copper or zinc wire. In the case of iron and copper wires, CSH and Ca(OH) 2 are formed in the paste at the interface. On the other hand, Ca[Zn(OH) 3·H 2O] 2, CSH and Ca(OH) 2 are formed in between C 3S paste and zinc wire. The relation between the development of bond strength and curing time is characteristic according to the kind of metal wires.

The constitution of adhesives, and its relationship to solvent abuse.

1 An adhesive, in general, must be a liquid at the time of application, so that the adherends are wetted out, but must then solidify to enable development of adequate bond strength. The use of volatile solvent is only one way in which the solid ingredients can be converted to a liquid for application. 2 Only those adhesives containing solvents are capable of providing the narcotic effect desired by the 'sniffer'. 3 Solvents used in adhesives include highly volatile hydrocarbons, esters, ketones and chlorinated hydrocarbons. 4 Commonly available domestic materials other than solvent-borne adhesives contain such solvents, and are hence capable of misuse by 'sniffers'. Often such materials are of greater potential harm to the mis-user. 5 Aversive additives in solvent-borne adhesives have been found ineffective and also deter the bona fide user. 6 Aqueous substitutes for existing popular and safely-used solvent-borne adhesives have not found sufficient favour with the domestic adhesive user as to enable the manufacturers to replace the solvent-borne type in the market place. 7 Removal of solvent-borne adhesives from the market would not of itself solve the problem of solvent abuse because of the other solvent sources available. The remedy lies in the removal of the causes of such social misbehaviour, rather than in treatment of the symptoms.

Urea Formaldehyde Resin Bond Strength Development with Reference to Wood Particleboard Manufacture

Urea Formaldehyde Resin Bond Strength Development with Reference to Wood Particleboard Manufacture

Effect of Water on Strength Development of Cold Setting Epoxy Resins

The bond strength development of epoxy resins was investigated by means of the shear and tensile bond strength methods. All the experiments were conducted in a low temperature laboratory controlled, at 4°C, 70per cent R. H.Firstly, the shear bond strength method of JIS K 6801 using birch timber of edge grain was applied. The moisture content of the adherent was of 6 kinds ranging from 10 to 106per cent, and the hardening time was of 4 kinds ranging from 1 to 8 days. The results were: (1) Water does not have so much deteriorating effect on the bond strength development of epoxy resins as on that of a polyvinyl acetate emulsion adhesive or an urea resin adhesive, (2) with epoxy resins a greater strength development is obtained at a smaller moisture content of wood, and (3) the usable range of moisture content of wood is under 32per cent with epoxy resin No. 1 and under 10per cent with epoxy resin No. 3, while epoxy resin No. 2 is not suitable for the purpose of adhesion of wood.Secondly, the tensile bond strength method using cement mortar briquette of ASTM C 190 was applied. The water content was of 5 kinds ranging from 3.2 to 8.0per cent, and the hardening time was of 3 kinds ranging from 1 to 4 days. The results were: (1) Water does not have so much deteriorating effect on the bond strength development of epoxy resins as on that of polyvinyl acetate solution adhesive, (2) with epoxy resins a greater strength development is obtained at a smaller water content of cement mortar, and (3) in case of the adhesion of finishing materials, the usable range of water content of cement mortar is under 8.0per cent with epoxy resins No. 1 or No. 2, while in case of the adhesion of structural materials, the usable range of water content of cement mortar is under 7.3per cent with No. 1 and under 3.2per cent with No. 2.

Tendencies of Development of Tensile Shearing Bond Strength in Cold Setting Epoxy Resins

The development of tensile shearing bond strength in 35 kinds of cold setting epoxy resins have been investigated according to ASTM D 1002-64. The experimental conditions were as follows: The adherend was an atmospheric corrosion resisting steel, the curing period was 1, 2, 4 or 8 days, and the curing was made under the atmospheric condition at 4°C in 65 per cent R. H. or the underwater condition at 4°C.The results show that the tendency of the strength development can be classified into three types; the increase curve type, the decrease curve type and the convex curve type. The latter two types basically belong to the same category because the decrease curve type also must have a peak. Their characteristics have to be improved by the addition of flexibilizer. In all cases, the strength reached a constant level at about 8 days' curing.The value of the strength at the constant level varied from 2 to 124kg/cm2 with the average value of 58kg/cm2 in the case of atmospheric curing, while it varied from 1 to 111kg/cm2 with the average value of 39kg/cm2 in the case of underwater curing. 28 kinds of the epoxy resin systems showed higher strength values in the case of atmospheric curing than those in the case of underwater curing, but other 7 kinds of epoxy resin systems showed the reverse results. The total average of the ratio in the strength between underwater curing and atmospheric curing for all the samples was about 65 per cent.