12 октября, 2015 
Pokraskin Among different industrial branches and trades, a variety of test methods for the evaluation of adhesively bonded joints have been developed and established, including the ISO (International Organization of Standardization), EN (European Committee for Standardization) and/or ASTM (American Society for Testing and Materials) standards.
While some test procedures require sophisticated equipment to assess the intrinsic material properties of the adhesive material, other test protocols may represent simple means to judge the characteristic properties of an application specific joint geometry on a comparative basis.
The basic test procedures to assess the bulk properties of cured adhesives include:
• stress-strain analysis of the bulk specimen
• determination of the glass transition temperature (Tg) by dynamic mechanical thermoanalysis (DMTA) or dynamic scanning calorimetry (DSC)
• determination of the coefficient of thermal expansion (CTE)
• temperature resistance by thermogravimetry (TG)
In general, the spectra of mechanical tests for adhesive joints can be subdivided by the type of mechanical stress to be created in the adhesive joint:
• tensile stress (e. g. butt joints)
• shear stress (e. g. single lap shear specimen)
• cleavage (e. g. wedge test)
• peel (e. g. 180° peel test)
In terms of timescale and test duration, the following test conditions may apply:
• short-time tests
• long-term static tests (e. g. creep experiments under dead load)
• impact tests (e. g. impact wedge test to evaluate the crash performance)
• cyclic loading (e. g. fatigue tests)
Mechanical tests are often combined with preceding aging procedures to evaluate the durability of adhesive joints. Reasonable aging cycles depend on the expected
in-service conditions of an adhesive joint. Accelerated aging tests typically include one or a combination of the following conditions:
• moisture
• immersion in water or other liquids
• elevated temperature
• cyclic freeze-thaw aging
• corrosive environment
• UV-exposure (for transparent adherents)
Further standards on adhesives relate to aspects of health and safety, storage and handling. Examples include:
• determination of words and phrases relating to the product life
• open time and working life
• extrudability
• sagging
• flammability
• volatile organic compound (VOC) emission
The current ISO CEN and ASTM databases contain some hundreds of standards related to adhesives which can be searched and accessed online at: http://www. iso. org, http://www. astm. org or http://www. cen. eu.
The European Guideline CEN/TR 14548 Adhesives — Guide to test methods and other standards for the general requirements, characterization and safety ofstructural adhesives, provides a detailed and comprehensive summary of up-to-date test methods for adhesives in structural applications. For nonstructural adhesives, industry-specific standards may apply, such as those of the Pressure-Sensitive Tape Council (PSTC), the Association des Fabricants Europeens de Rubans Auto-Adhesifs (AFERA) or the Federation Internationale des Fabricants et Transformateurs d’Adhesives et Thermo — collants sur Papier et autres Supports (FINAT). Therefore, the scope of this chapter is limited to the basic principles and concepts of adhesive testing, and does not aim to provide a full coverage of currently active standards.
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