Adhesion polymer

S. Wu, Former Interface andfidhesion Marcel Dekker, New York, 1982. A basic textbook covering surface effects on polymer adhesion. 

Applications of ISS to polymer analysis can provide some extremely useful and unique information that cannot be obtained by other means. This makes it extremely complementary to use ISS with other techniques, such as XPS and static SIMS. Some particularly important applications include the analysis of oxidation or degradation of polymers, adhesive failures, delaminations, silicone contamination, discolorations, and contamination by both organic or inorganic materials within the very outer layers of a sample. XPS and static SIMS are extremely comple-mentar when used in these studies, although these contaminants often are undetected by XPS and too complex because of interferences in SIMS. The concentration, and especially the thickness, of these thin surfiice layers has been found to have profound affects on adhesion. Besides problems in adhesion, ISS has proven very useful in studies related to printing operations, which are extremely sensitive to surface chemistry in the very outer layers. 

Another example of static SIMS used in a more quantitative role is in the analysis of extmded polymer blends. The morphology of blended polymers processed by extrusion or molding can be affected by the melt temperature, and pressure, etc. The surface morphology can have an effect on the properties of the molded polymer. Adhesion, mechanical properties, and physical appearance are just a few properties affected by processing conditions. 

Lee, I. and Wool, R.P, Thermodynamic analysis of polymer adhesion sticker and receptor group effects. J. Polym. Sci. Phys Ed., submitted. 

The primary challenge facing adhesive bonding of metals is to obtain sufficient durability of a bonded structure. Initial bond strength in metal-polymer adhesive joints is almost invariably excellent. Challenging the application of adhesives in polymer-polymer joining, however, is the problem of obtaining a joint that is... 

There are many obstacles to permanent adhesion under oral conditions. The substrate is a biological tissue and subject to change, and the presence of moisture represents the worst kind of situation for adhesion. Water is the great barrier to adhesion. It competes for the polar surface of tooth material against any potential polymer adhesive. It also tends to hydrolyse any adhesive bond formed. These twin obstacles gave rise to considerable doubt as to whether materials adhesive to tooth material could be developed at all (Cornell, 1961). 

The original applications of NIR were in the food and agricultural industries where the routine determination of the moisture content of foodstuffs, the protein content of grain and the fat content of edible oils and meats at the 1% level and above are typical examples. The range of industries now using the technique is much wider and includes pharmaceutical, polymer, adhesives and textile companies. The first in particular are employing NIR spectrometry for the quality control of raw materials and intermediates and to check on actives and excipients in formulated products. Figure 9.26(b) demonstrates that even subtle differences between the NIR spectra of enantiomers can be detected. 

Basic Mechanisms of Adhesion Acid-Base Interactions. The understanding of polymer adhesion has been greatly advanced in recent years by the recognition of the central role of acid-base interactions. The concept of an acid was broadened by G. N. Lewis to include those atoms, molecules, or ions in which at least one atom has a vacant orbital into which a pair of electrons can be accepted. Similarly, a base is regarded as an entity which possesses a pair of electrons which are not already Involved in a covalent bond. The products of acid-base interactions have been called coordination compounds, adducts, acid-base complexes, and other such names. The concept that... 

Moore, D., Pavan, A., and Williams, J. 2001. Fracture Mechanics Testing Methods for Polymers, Adhesives, and Composites. Elsevier, New York. 

Crosby AJ (2003) Combinatorial characterization of polymer adhesion. J Mater Sci 38 4439-4449... 

The polymerization of alkyl vinyl ethers is of some commercial importance. The homopolymers, which can be obtained only by cationic polymerization, are useful as plasticizers of other polymers, adhesives, and coatings. (The copolymerization of vinyl ethers with acrylates, vinyl acetate, maleic anhydride, and other monomers is achieved by radical polymerization but not the homopolymerizations of alkyl vinyl ethers.)... 

The predominant applications of present day metal/polymer adhesion technology are for the development of strong metal-to-metal structural adhesive joints and durable protective coatings. 

This review will first present the metal/epoxy resin adhesive system and discuss how the presence of metal oxides influences adhesion secondly, present the reasons why these systems exhibit very good adhesion strength under dry conditions and why this adhesion strength is greatly reduced in the presence of water thirdly, examine possible methods of increasing their durability in wet environments and finally, discuss some of the spectroscopic techniques that are currently being used to aid in the advancement of metal/polymer adhesion technology. 

Metal/Polymer Adhesion System 2.1 Metal Surface... 

Figure 3 241 illustrates that the durability of metal/polymer adhesion systems can greatly be influenced by the metal pretreatment chosen 1 K Therefore, it is very important to select the best pretreatment for a given system. 

All adhesion scientists will agree that water is a very destructive environment for metal/polymer adhesion systems (see Fig. 5). Since water is one of the most commoi environments encountered, the effectiveness of metal/polymer coating and structural bonding systems has been severely limited by this great loss of adhesion strength in the presence of water. 

In the past, the detrimental effect of internal stresses on adhesion strength has often been ignored. Conversely, in a few cases, the presence of internal stresses has been proposed as the primary reason for adhesive failure96 "-104-108) authors believe that internal stresses can play an important role in reducing the adhesion strength of metal/epoxy systems and that the theories developed by Croll 96 102) and Shimbo et al.99) should lead to an increased awareness of this fact. In addition, further work must be completed in this area so that the usefulness of these theories and the effect of internal stresses on metal/polymer adhesion systems can be successfully analyzed. 

In Section 4.2, the strength loss mechanisms of metal/polymer adhesion systems in the presence of water were discussed. From this discussion it is evident that high initial adhesion strength is not the only important property of these systems. Actually, if a metal/polymer adhesion system is exposed to humid environments, it is more important for the system to exhibit good durability. 

Over the past fifteen years a number of different approaches have been taken in an attempt to increase the durability of the metal/polymer interfacial region in the presence of water. These attempts have met with varied degrees of success. However, to date adhesion scientists are still searching for a means of achieving sufficient wet environment durability, so that the enormous potential of metal/polymer adhesion systems can soon be utilized effectively. The authors have selected to discuss a few of the more promising durability-enhancing methods. 

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