Polyurethane Surface treatment

The use of chlorination as surface treatment to improve the adhesion of mbbers to polyurethane adhesives was proposed in 1971. The employ of chlorination in the industry is due to its high effectiveness in improving the adhesion of several types and formulations of mbbers, it is cheap and easy to apply. Furthermore, chlorination makes the mbber surface compatible with many adhesives... 

Polymer-based pH sensors are not suitable for continuous in-vivo measurements due to the poor biocompatibility of plasticizers used in the polymer membrane. To minimize such a problem, surface treatment or using a reduced amount of plasticizers has been proposed [71]. In order to improve stability and adhesion, polyurethane has been used as an alternative to PVC membranes in the construction of pH sensing membranes [72, 73],... 

The glass fibre, PPG 3540, is a polyurethane-sized glass fibre manufactured by PPG Industries, Inc. The surface treatment on the glass fibre promotes good adhesion between the fibre and the polymer. b Note montmorillonite is surface treated with octadecylammonium or dioctadecyldimethylammo-nium ions. 

Joining is possible with adhesives such as epoxies, acrylates, cyanoacrylates, polyurethanes. Surface treatments can be useful. Preliminary tests are essential. 

Reference to Table 7 will show the data for the two-pack polyurethane paint, and indicate a similar improvement to that of the epoxide paint due to the use of silanes. Although there are differences in the values for particular silanes on the different substrates and surface treatments, the general picture is that AAMS and MPS are the most effective in epoxide and polyurethane paints. 

Presently DOE is funding Air Products Chemical Company for the development of a fluorine surface treatment of tire rubber (crumb rubber) to modify its adhesion properties. This modified rubber could be used in making polymers such as polyurethane and epoxies. The tire rubber might also be used in certain plastics such as polystyrene and PVC, and in rubber products (68). 

Surface treatment of textiles, leather, glass, wood, and paper is the second largest application for fluorinated polyurethanes. The coatings are applied in one-step treatment and impart resistance to soil, water, oil, and stains as well as a smoothness to fabrics and leather that resists removal by many cycles of laundering or dry cleaning.52... 

Cellulosics are normally solvent-cemented unless they are to be joined to another substrate. In these cases, conventional adhesive bonding is employed. Polyurethane, epoxy, and cyanoacrylate adhesives are commonly used to bond cellulosics. Surface treatment generally consists of solvent cleaning and abrasion. Cellulosics can be stress-cracked by uncured cyanoacrylate adhesives and some components of acrylic adhesives. A recommended surface cleaner is isopropyl alcohol. 

Polyurethane coatings can be used for remedial applications in sewers and effluent-treatment plants, but they are suitable for milder conditions only. Two-pack polyurethane coatings are employed in this case. However, difficulties may be encountered during application if the system is sensitive to surface moisture. Polyurethane coatings in such applications need several coats to attain the necessary film thickness. 

Both, aniline and anilium hydrochloride were polymerized in direct and in inverse miniemulsion, respectively [140]. The polymerization of anilium hydrochloride, which was initiated by hydrogen peroxide, yielded a highly crystaUine emeraldine polyaniline. In direct miniemulsions, additional stabilizers (e.g., poly(vinyl pyrroU-done) or PVA) were employed to preserve colloidal stability. The polymerization of aniline in direct miniemulsion has also been reported [141] in this case, following polymerization the polymer was first treated with stannous chloride and then doped with p-toluenesulfonic acid. A dramatic increase in conductivity after treatment with stannous chloride was considered due to pernigraniline moiety in the emeraldine base structure having been reduced. Such oxidative polymerization of aniline may be used to add an additional conductive shell to preformed latexes. For example, Li et al. polymerized aniline in the presence of dodecylbenzesulfonic acid on the surface of polyurethane and polyurethane/poly(methyl methacrylate) nanoparticles prepared in miniemulsion [142]. 

Effect of Amine Surface Treatment on the Adhesion of a Polyurethane to the Surface... 

In polyurethane synthesis, amines are used both as chain extenders and as curing agents. The chemical reactions that occur and the products that form are well known (9-11). The questions that this study addressed were two. How does the structure of the amine used affect the adhesive properties of the resulting polyurethane and how can the observed effects be explained This paper describes the synthesis and characterization of a new elastomeric polyurethane that shows remarkably high adhesion to glass and other substrates. A positive effect of amine surface treatment of the substrates on the adhesion of the polyurethane to the substrates is also reported. The results are interpreted in terms of the structure of the amines and of the polyurethane formed. 

EFFECT OF SURFACE TREATMENT ON POLYURETHANE Surface Treatment of Substrates... 

The chemical reactions occurring are probably similar to those described above for glass (22). Supporting evidence that amino compounds are chemisorbed by metal oxide surfaces has recently been obtained by inelastic tunnelling spectroscopy (23). Further investigations are being carried out to find explanations for the differences observed in the effects of amine surface treatment of glass and of metal on the adhesion of this polyurethane to the substrate. 

The predominant failure mode in bonded joints was cohesive failure of the adherend. Only in those adhesively bonded joints with the polyurethane adhesive (1897) was a cohesive failure of the adhesive encountered. No adhesive failures were detected, indicating that the surface treatments performed had been sufficient. The quality of adhesive layers was in general satisfactory. However, in joints of laminates with a woven roving or a uni-directional surface layer (Table 7) the adhesive layers were thick and of poor quality, having large voids. With laminates of a uni-directional surface layer, this... 

Segmented polyurethanes have good resistance to thromboresistance plus exceptionally good physical properties which makes them unique. Also special surface treatment of the PU is not usually required for heparin anticoagulant attachment, hydrogel grafting, nor blood treatment with... 

Rimplast (Trade name of Petrarch Systems, USA). These are a series of IPN blends of high molecular weight silicone rubber with polyurethane. Toyoho (Trade name of Toyobo, Japan). A series similar to those of Biomer. Transparent PU elastomers. These are based on aliphatic diisocyanates and used for artificial organs. Compatibility with blood is achieved through either the incorporation of polysiloxane or surface treatment of the PU with heparin or albumen. 

Although general purpose polyurethane adhesives have been used for over 40 years, it is only within the last two decades that structural adhesives based on polyurethanes have made significant inroads into the marketplace. This is due to the advances in urethane technology and to the advent of synthetic structural materials such as fiber-reinforced plastics (FRPs). These materials are readily bonded, with minimal surface treatment, using polyurethane structural adhesives. 

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