Adhesive modifications

Acryhc stmctural adhesives have been modified by elastomers in order to obtain a phase-separated, toughened system. A significant contribution in this technology has been made in which acryhc adhesives were modified by the addition of chlorosulfonated polyethylene to obtain a phase-separated stmctural adhesive (11). Such adhesives also contain methyl methacrylate, glacial methacrylic acid, and cross-linkers such as ethylene glycol dimethacrylate [97-90-5]. The polymerization initiation system, which includes cumene hydroperoxide, N,1S7-dimethyl- -toluidine, and saccharin, can be apphed to the adherend surface as a primer, or it can be formulated as the second part of a two-part adhesive. Modification of cyanoacrylates using elastomers has also been attempted copolymers of acrylonitrile, butadiene, and styrene ethylene copolymers with methylacrylate or copolymers of methacrylates with butadiene and styrene have been used. However, because of the extreme reactivity of the monomer, modification of cyanoacrylate adhesives is very difficult and material purity is essential in order to be able to modify the cyanoacrylate without causing premature reaction. 

This paper is a commercial survey covering recent developments in urethane coatings and adhesives with reduced solvent contents. There are many aspects of urethane chemistry which make polyurethanes an ideal base for nonsolvent coatings developments. However, in order to achieve practical handling behavior for coatings adhesives, modifications of classical urethane chemistry are needed. 

MAJOR APPLICATIONS Hoses where oil, fuel, chemicals, and solutions are transported. Oil-drilling industry. Powder and particulate forms in cements and adhesives. Modification of PVC and ABS to improve impact resistance. 

L.G. Beholz, C.L. Aronson, A. Zand, Adhesion modification of polyolefin surfaces with sodium h)qK)chlorite in acidic media. Polymer 46, 4604-4613 (2005)... 

Figure 3. Coating-wood adhesion modifications as a function of plasma treatment for black spruce. Values were calculated with reference to an untreated control specimen (/Vef)- A represents the strength needed to pull-off the coating after plasma exposure.

Some of the more recent research efforts that may lead to new adhesive types are categorized as follows (1) adhesives from natural products, (2) adhesives generated in situ in the wood, (3) adhesive modifications to facilitate processing, and 4) adhesive modification for improved properties. Examples of these approaches are given below. 

Adhesive coating Ease of adhesive coating after surface treatment or adhesive modification Ease of postfabrication Smooth surface Regular cellular structure Wide range of mechanical properties Pressure-sensitive adhesive coated applications, tapes, strips, pad, joints and gaskets... 

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