Adhesives and Sealants - August 2009
This month we're focusing on the topic of polymers as Adhesives and Sealants
Adhesives have been around for many centuries, but the relatively recent development of synthetic polymer-based adhesives has seen considerable improvements, both in terms of the adhesive properties and the range on offer. The different types currently available include contact, hot melt, pressure sensitive, two-part and UV light cured and the right adhesive can be selected based on the nature of the application. Factors to consider include the type of material being bonded and the environment it will be subjected to.
Although they serve similar functions, there is a subtle distinction between the categories of 'adhesives' and 'sealants'. The role of a sealant lies with joining two surfaces by filling existing gaps and thereby providing a barrier to liquids/gases etc, whereas an adhesive usually just focusses on sticking two surfaces together as closely as possible. Despite minor differences, both adhesives and sealants play an important role in every day lives - you don't often notice them, but they are all around us!
Abstracts
Please see below a selection of abstracts highlighted in the August Newsletter. These are records which relate to Adhesives and Sealants that have been recently added to the Polymer Library.
Click on the 7-digit accession numbers to find out about ordering a copyright-cleared full text copy of the items shown.
1044448 - RESEARCH OF SILVER PLATING NANO-GRAPHITE FILLED CONDUCTIVE ADHESIVE
Silver plating nano-graphite was prepared by electroless plating using nano-graphite obtained from expanded graphite and evaluated as a filler in an epoxy resin adhesive cured with triethanolamine. The electrical properties and thermal stabilities of the filled adhesive were investigated as well as the mechanical properties of adhesive joints with carbon steel adherends. The adhesives exhibited two percolation threshold values and good heat stablity. 18 refs.
Synthetic Metals, 159, No.7-8, April 2009, p.619-624, ISSN: 0379-6779, DOI: 10.1016/j.synthmet.2008.12.003
Wei Lin; Xiangrong Xi; Chaosheng Yu
1044151 - AN ATTEMPT AT FINDING A CORRELATION BETWEEN ENVIRONMENTAL AND ACCELERATED RILEM TC 139-DBS WEATHERING FOR ONE-COMPONENT POLYURETHANE SEALANTS APPLIED ON MORTAR
The durability of butt joint test specimens with mortar substrate prepared using thixotropic or self-levelling low modulus and high modulus one-component polyurethane sealants was investigated under natural outdoor weathering conditions in Milan, Italy, and by accelerated weathering in a light exposure apparatus with water spray according to RILEM TC 139 DBS. Specimens were visually inspected at specified intervals for crack density and size, and the results are discussed in terms of the correlation between those obtained by outdoor exposure and by RILEM durability cycling. 14 refs.
Journal of ASTM International, 6, No.4, April 2009, Paper ID: JAI101965, pp.9
Pozzi E; Carcano V; Ausilio A
1044150 - LONG-TERM OUTDOOR WEATHERING STUDY OF CONSTRUCTION SEALANTS
The durability of a range of commercial sealant products for construction applications, based on silicone, polyurethane or acrylic terpolymer with fumed silica and/or calcium carbonate as fillers was investigated by long-term outdoor weathering studies carried out in Miami, Florida, for a period of 22 years. The performance of the sealants applied to glass and painted aluminium substrates was monitored over that period for appearance (surface irregularities), elastic recovery, flexibility, hardness and adhesion, and each sealant was assigned a durability ranking.
Journal of ASTM International, 6, No.4, April 2009, Paper ID: JAI101946, pp.24
Bull E D; Lucas G M
1044097 - MORPHOLOGY AND PROPERTIES OF WATERBORNE POLYURETHANE/CNT NANOCOMPOSITE ADHESIVES WITH VARIOUS CARBOXYL ACID SALT GROUPS
The synthesis of three series of waterborne nanocomposite adhesives of polyurethane with various proportions of multiwall carbon nanotubes (CNTs) by reaction of poly(tetramethylene glycol) and various amounts of 2,2-dimethylolpropionic acid (DMPA) with 4,4-dicyclohexylmethane diisocyanate in the presence of CNTs followed by solution casting and curing at different temperatures is described. The products were characterised by TEM, TGA, tensile strength, tensile modulus, elongation and T-peel testing, and the effects of DMPA content on CNT dispersion, and of CNT content on adhesive and mechanical properties are discussed. 24 refs.
Journal of Adhesion Science and Technology, 23, No.6, 2009, p.839-850, ISSN: 0169-4243, DOI: 10.1163/156856109X411210
Rahman M M; Kim E Y; Lim K T; Lee W-K
1043933 - PLASMA AND ADHESION TO RUBBER, PLASTICS SUBSTRATES
World-class, fully automated manufacturing processes rely more and more on advanced, environmentally friendly surface treatment technologies. An innovative atmospheric pressure plasma technique allows inline rubber and plastic manufacturing processes to become fully automated with total process control. A thorough pre-treatment must produce surfaces with reliable and repeatable characteristics to achieve optimal adhesive bonding, coating and printing results. In addition, pre-treatment must be delivered in a cost-effective and safe manner. The new process uses the high effectiveness of plasma for microfine cleaning, high surface activation and nanocoating. In most cases, the plasma application takes the place of environmentally unfriendly and costly solvent cleaning or chemical adhesion promoters and primers. 3 refs.
Rubber and Plastics News, 38, No.23, 15th June 2009, p.16-19, ISSN: 0300-6123
Glogauer S
1043749 - STICKING TO LIGHT-CURE ADHESIVES
Following a discussion of the mechanism, benefits and key considerations of light-curing adhesives, a report is presented on the additional light-cure technologies that have been introduced over the last decade to assist medical device manufacturers with their assembly processes. The technologies described include biocompatible light-curing epoxies, cyanoacrylates and silicones, as well as acrylics that cure with pure visible light.
Medical Device and Diagnostic Industry, 31, No.5, May 2009, p.44/48, ISSN: 0194-844X
Marotta C S
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