Primers materials

Low surface energy substrates, such as polyethylene or polypropylene, are generally difficult to bond with adhesives. However, cyanoacrylate-based adhesives can be effectively utilized to bond polyolefins with the use of the proper primer/activa-tor on the surface. Primer materials include tertiary aliphatic and aromatic amines, trialkyl ammonium carboxylate salts, tetraalkyl ammonium salts, phosphines, and organometallic compounds, which are initiators for alkyl cyanoacrylate polymerization [33-36]. The primer is applied as a dilute solution to the polyolefin surface, solvent is allowed to evaporate, and the specimens are assembled with a small amount of the adhesive. With the use of primers, adhesive strength can be so strong that substrate failure occurs during the course of the shear tests, as shown in Fig. 11. 

Trinitrotoluene DNT Tetryl Primer materials < s Nitrocellulose j Nitroglycerin 1 j NC-based propellants j Ball Powder j 0> > o PL. -o ra 55 Acid manufacture J Filling of warheads Mfg of extruded rocket grains j Mfg of cast rocket grains... 

Figure 1. An example of cathodic blistering. The coating was a zinc chromate alkyd primer material. The electrolyte was 0.5M KCl and the potential of the metal was maintained at - 1.0 v vs, SCE.

An examination of the current anarchist literature enforces this point. The term anarchist literature is used to refer to the dozens of books that have historically been available through mail order companies such as Desert Publications and Paladin Press dealing with the production of explosives and bombs. Many of these sources are still copied today as primer material to train current A1 Qaeda bomb makers. The same information has been disseminated over the Internet in numerous bomb-making websites. 

K chlorate PA Pb nitrate Tetryl and Pb nitride TNT) 22-3 (Nature of priming compositions) 23-5 (Primer composition materials) 25 (Sampling of primer materials) 25 (Identification of primer materials) ... 

Primers, primer materials and detonators should never he stored with other high explosives. A separate building or annex to an explosive store is usually desirable for keeping detonators. Similarly, black powder must also be kept in separate locations away from high explosives. 

Perhaps because it can be made into primer material as well as other high-grade explosives, standard hexamine is increasingly more difficult to find in stores. Traditionally, boy scouts among us have used it for fire in their little camp stoves. In the past, it was easy to purchase almost anywhere-... 

Friction primers are any device composed of an energetic material which is capable of producing a flame from frictional energy. A frictional primer material common to all households is the kitchen match. When used in field-expedient applications, the kitchen match does have explosives application as a primer. However, the fihetion-... 

For the Boxer primer, a stiff, convex, two- or three-leaf circular metal foil is pressed into the cup after the primer material. This metal foil is bent so that the center is in contact with the primer material and the outer edges of the leafs are secured to the rim of the cup. In this way the center of the foil acts as an anvil when the outer surface of the cup is struck by a firing pin. 

The bond between rubber and the metal surface is essentially a mechanical one achieved by the use of various resins and chlorinated rubbers, which when heated and crosslinked within their mass form a rigid network. Subsequent application of a high temperature directly to the area of the bond will result in the loosening of the grip of the primer material, and under the application of a load the bond will fail. This method is sometimes used to reprocess metals from components which have been rejected by quality tests. 

When cultures or enzyme preparations of N. perfiava are allowed to act on a-D-glucose-l-phosphate, some amylopolysaccharide is produced, indicating the presence of a phosphorylase. However, the amylosucrase can be distinguished from the bacterial phosphorylase by its stability to heat and by the fact that the synthesis of the polysaccharide from sucrose is not suppressed in high concentration of inorganic phosphate. The synthetic reaction proceeds without a noticeable lag period, suggesting that primer material, if needed, is present in the preparations. Although there is no direct evidence for this, the fact that the formation of polysaccharide is completely inhibited in the presence of traces of salivary amylase indicates that a primer may be required. 

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. 

Materials and Reactions. Candle systems vary in mechanical design and shape but contain the same genetic components (Fig. 1). The candle mass contains a cone of material high in iron which initiates reaction of the soHd chlorate composite. Reaction of the cone material is started by a flash powder train fired by a spring-actuated hammer against a primer. An electrically heated wire has also been used. The candle is wrapped in insulation and held in an outer housing that is equipped with a gas exit port and rehef valve. Other elements of the assembly include gas-conditioning filters and chemicals and supports for vibration and shock resistance (4). 

The TH3 core is ignited by the primer, and the burning core then melts and ignites the magnesium alloy body of the bomb. The incendiary action on the target is localized. There is Utde scattering of the incendiary material. 

Powder coatings as a class are superior to Hquid coatings in abiHty to coat sharp edges and isolate the substrate from contact with corrosive environments. PVC coatings are softer and more flexible than any of the other powder coating materials. Primers used for PVC plastisols have been found generally suitable for powder coatings as weH (5). 

The wash primer is a special type of vinyl coating. This material contains a poly(vinyl butyral) resin, zinc chromate, and phosphoric acid in an alcohol-water solvent. The coating is so thin it is HteraUy washed onto a freshly blasted steel surface, where it passivates the metal surface by converting it to a thin iron phosphate-chromate coating. The alcohol solvent makes it possible to apply the coating over damp surfaces. The coating forms the first coat of... 

Hypalon CP 826. This is a chloriaated, maleic anhydride modified polypropylene having a chlorine content of about 25% and maleic anhydride content of about 0.8%, developed to promote adhesion of inks and coatiags to polypropyleae or bleads containing polypropyleae. It has a solutioa viscosity of 125 mPas(= cP) at 20% soHds ia xyleae and can be used ia dilute solutioas as a wash primer or a tie layer betweea materials that are difficult to adhere. CP 827 is a higher molecular-weight analogue with a solution viscosity of 280 mPas(= cP) at 20% soHds ia 80/20 xylene/methyl isobutyl ketoae. 

D. B. Williams. Practical Analytical Electron Microscopy in Materials Science. Verlag Chemie International, Weinheim, 1984. A good monograph discussing the use and applications of AEM, especially at intermediate voltages. The discussion on EDS is an excellent primer for using X-ray analysis on a TEM. 

The use of chemical mapping is demonstrated in the following example involving the delamination of a silicone primer and polytetrafluoroethylene (PTFE) material. The positive mass spectrum acquired from the delaminated interface contains peaks known to be uniquely characteristic of PTFE (CF3 at mass 69) and the silicone primer (Si(CH3)3 at mass 73). Figures 6 and 7 are secondary ion im es of the CF3 and (Si(CH3)3 fragments taken from a 1-mm area of the delaminated interface. These maps clearly indicate that the PTFE and the silicone primer exist in well-defined and complementary areas. 

Poly(vinyl acetal) itself is now of little commercial importance. The material may be injection moulded but has no particular properties which merit its use. It is occasionally used in conjunction with nitrocellulose in lacquers, as a vehicle for wash primers and as a stiffener for fabrics. 

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