Sealants commercially available

Hydrocarbon resins are used extensively as modifiers in adhesives, sealants, printing inks, paints and varnishes, plastics, road marking, flooring, and oil field appHcations. In most cases, they ate compounded with elastomers, plastics, waxes, or oils. Selection of a resin for a particular appHcation is dependent on composition, molecular weight, color, and oxidative and thermal stabiHty, as weU as cost. A listing of all hydrocarbon resin suppHers and the types of resins that they produce is impractical. A representative listing of commercially available hydrocarbon resins and their suppHers is included in Table 6. 

A partially cross-linked, isobutylene—isoprene—divinylbenzene terpolymer containing some unreacted substituted vinylbenzene appendages is commercially available from Polysar Division, Bayer AG. Because of the residual reactive functionality, it can be cross-linked by peroxides that degrade conventional butyl mbbets. It is employed primarily in the manufacture of sealant tapes and caulking compounds (31). 

Prior to May of 1998 when the commercial product was approved by the FDA in the United States, surgeons in this country formed fibrin sealant by using topical bovine thrombin, which is a commercially available product, together with concentrated fibrinogen most frequently obtained from the blood bank. Standard blood bank cryoprecipitate is a good source of concentrated fibrinogen. Also... 

Operating conditions are important determinants of the choice of filter media and sealant used in the cartridges. Some filter media, such as cellulose paper filters, are useful only at relatively low temperatures of 95 to 150"C (200 to 300°F). For high-temperature flue gas streams, more thermally stable filter media, such as nonwoven polyester, polypropylene, or Nomex, must be used. A variety of commercially available sealants such as polyurethane plastic and epoxy will allow fabric operating temperatures up tol50°C (300°F). Selected sealants such as heat cured Plasitcol will withstand operating temperatures up to 200°C (400°F). 

Silicones. Commercially available silicone sealants are typically one of three curing types moisture-reactive (curing) sealants, moisture-releasing (latex) sealants, and addition-curing sealants. Of these three types, moisture-curing silicones make up the vast majority of silicone sealants sold. 

Highest molecular weight and most permanent monomeric phthalate plasticizer commercially available. Used for high temperature rated PVC insulation. Other end uses include traffic cones, automotive sealants, fabric coatings, fishing lures and shoe compounds. 

The hydroxyl-terminated homo- and copolymers of butadiene have been utilized in the preparation or modification of urethane elastomers and sealants (102). Owing to the presence of unsaturation in these polymers, reinforcement with certain fillers such as carbon black can be achieved. Hydroxyl-terminated polyisobutylenes have also been used for the preparation of NCO-terminated prepolymers (103). Very recently (104). a,u-di-(hydroxy)polyisobutylenes have been prepared by a different route. Polyurethane films prepared from these polyisobutylene glycols have exhibited excellent hydrolytic stability and very low water absorption (105). However, these materials are not yet commercially available. 

Elastomeric materials are used in thermal solar collectors as gasket and caulking compounds. In addition to these sealant applications, polymeric materials are also widely employed as thermal insulation and occasionally as glazing and frame components. This paper provides a supplement and a continuation of a previously reported study( 1) of the endurances of several commercially available sealants to the harsh environment of the collector. 

The various silicone sealants now available provide a broad spectrum of physical properties. For example, ultimate elongation (as measured by ASTM-D-412) varies from 50% to 1200% and one commercially available silicone sealant- has a typical value of >1200% with almost 100% recovery. Tensile strengths vary from 100 to 1000 psi, while moduli at 100% extension range from <50 to >500 psi. Durometer hardnesses can range from 15 to 80 (Shore A). 

In the preceding discussion we dealt with BTZs and HALSs as classes of light stabilizer without much attention to structure variations within each class. As demonstrated by the numerous chapters of this book, many polymers are used for adhesive applications. Each of these materials may have unique photostability concerns. It is beyond the scope of this chapter to address the stabilization of specific adhesives. Similarly, it is beyond our scope to discuss the many structural variations of UVA and HALS chemistry. Many derivatives of these compounds are commercially available, and some adhesive and sealant formulations and/or applications may dictate the use of one stabilizer over another. 

Today, flowable materials are used not only for most classes of restoring teeth, but also as fissure sealants. Current products differ considerably in formulation and filler content (Beun et al., 2008). Fissure sealants contain less than 25% inorganic filler, while conventional flowable filling materials have about 50-70% filler. Consequently there are considerable differences in properties between commercially available products. Beun et al. (2008) have studied the effect of these variations on rheological properties including storage modulus, and classified the products into three groups, based on their sohd-like behavior. 

Actually, a few years ago, Hergenrother [86] stated the precise requirements of the technology for high speed civil transports (HSCTs) the sealants must exhibit a combination of properties such as elongation, moderate peel strength, fuel resistance and performance for 60000 h at 177 °C. He said that the most popular commercially available fuel tank sealant that can be used at a temperature of around 177°C is based upon poly(3,3,3-trifluoropropyl methylsiloxane), but this product may degrade after continued exposure to high temperature. 

Isobutylene-lsoprene-Divinylbenzene Terpolymers. A partially cross-linked terpolymer of isobutylene, isoprene, and partially reacted divinyl benzene is commercially available from Rubber Division, Bayer Inc., Canada. The residual vinyl functionality may be cross-linked with peroxides, a treatment that would normally degrade conventional butyl rubbers. This material is used primarily in the manufacture of sealant tapes and caulking compounds (45). 

Fillers, especially high surface area silicas, are commercially available with such hydrophobic surface coatings. They are expensive and seem to be mainly used in sealant and adhesive applications rather than in polymer composites, where they produce low particle matrix adhesion similar to fatty acid and other cheaper additives. 

Concrete sealants have often been used as a means of finishing industrial floors for spillproofing or wear resistance. These coating techniques have some applicability to PCB contamination situations on the principle that a sound coating material would at least temporarily inhibit human exposure in the work place. Several coating materials are commercially available and touted as specifically applicable to PCB decontamination. 

As mentioned above, both thermoplastic and thermosetting type acrylic resins are commercially available for coatings, elastomers, sealants and adhesive applications. These resins are supplied in many different delivery forms such as powders or pellets, solutions in organic solvents and aqueous dispersions. These resin types are briefly described below. 

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