Polymeric plasticizers class

Plasticizers can be classified according to their chemical nature. The most important classes of plasticizers used in rubber adhesives are phthalates, polymeric plasticizers, and esters. The group phthalate plasticizers constitutes the biggest and most widely used plasticizers. The linear alkyl phthalates impart improved low-temperature performance and have reduced volatility. Most of the polymeric plasticizers are saturated polyesters obtained by reaction of a diol with a dicarboxylic acid. The most common diols are propanediol, 1,3- and 1,4-butanediol, and 1,6-hexanediol. Adipic, phthalic and sebacic acids are common carboxylic acids used in the manufacture of polymeric plasticizers. Some poly-hydroxybutyrates are used in rubber adhesive formulations. Both the molecular weight and the chemical nature determine the performance of the polymeric plasticizers. Increasing the molecular weight reduces the volatility of the plasticizer but reduces the plasticizing efficiency and low-temperature properties. Typical esters used as plasticizers are n-butyl acetate and cellulose acetobutyrate. 

There are five classes of plasticizers normally employed for polychloroprene vulcanization (1) organic esters, (2) petrolenm oils, (3) vegetable oils, (4) chlorinated paraffins, and (5) polymeric plasticizers (Table 8). Some attributes of the different classes follow ... 

The class of specialty plasticizers includes a variety of different products, which share two things in common they are used in relatively few applications and are usually available at often significant price premiums over GP plasticizers. Consequently they are used in those applications where the added performance benefits are required and the ultimate customer is willing to pay extra for that added performance. Examples of plasticizers in this classification would include polymeric plasticizers, epoxides, phosphate esters, citrates, brominated phthalate esters, polyol ester plasticizers, and a variety of natural product based plasticizers. 

The largest class of polymeric plasticizers is polyesters, which are prepared by the reaction of differing diols, dibasic acids (such as adipic acid or phthalic anhydride), and an aliphatic primary alcohol or an aliphatic acid acting as a chain stopper to help control the molecular weight. These products typically range from high viscosity liquids to gels or semisolids at room temperature. Polymeric plasticizers offer improved performance in resistance of plasticizer extraction by solvents or oils, resistance to... 

Besides polymeries and benzoates, there are several other important classes of specialty plasticizers. Citric acid esters form another such class, as well as those of adipates, trimellitates, specialty phthalates, epoxidized soybean oil, and phosphates. All of these add value to vinyl compositions that general pmpose plasticizers cannot. The focus for this chapter is on benzoates, polymeries and citrates. Not every benzoate, polyester polymeric plasticizer, and citrate ester will be catalogued in this chapter. An understanding of these plasticizers, how they function, and how to use them to advantage in formulation of flexible vinyl compositions is the desired outcome of the investment in reading time. 

Different types of polymers can be used to plasticize PVC compositions. For example, nitrile mbber (NBR), thermoplastic polyurethane, and ethylene vinyl acetate(EVA) co- and terpolymers can be used to alloy with PVC. These types of compositions are discussed in Chapter 15. This section will focus on the class of polyesto polymeric plasticizers. These have average molecular weights ranging from less than 1000 to about 25,000, and are viscous liquids to semisolids at room temperature. 

Polymeric plasticizers are specialty types that are used in PVC formulations when extraordinary migration and extraction resistance are required. While different chemical classes of polymeric plasticizers are used, the most common type in the PVC market are liquid or near liquid polyester adipates. Typically, these polymeric plasticizers are in the 1000 to 13,000 molecular weight range (MW). While polymeric plasticizers have been used in PVC compounding for many years, developments continue. New polymeric plasticizers were developed for improved printing with waterborne inks and improved processing characteristics. This paper focuses on two new products and how they provide the required printability and processing characteristics. 

Nylon A class of synthetic fibres and plastics, polyamides. Manufactured by condensation polymerization of ct, oj-aminomonocarboxylic acids or of aliphatic diamines with aliphatic dicarboxylic acids. Also rormed specifically, e.g. from caprolactam. The different Nylons are identified by reference to the carbon numbers of the diacid and diamine (e.g. Nylon 66 is from hexamethylene diamine and adipic acid). Thermoplastic materials with high m.p., insolubility, toughness, impact resistance, low friction. Used in monofilaments, textiles, cables, insulation and in packing materials. U.S. production 1983 11 megatonnes. 

Random copolymers of vinyl chloride and other monomers are important commercially. Most of these materials are produced by suspension or emulsion polymerization using free-radical initiators. Important producers for vinyl chloride—vinyUdene chloride copolymers include Borden, Inc. and Dow. These copolymers are used in specialized coatings appHcations because of their enhanced solubiUty and as extender resins in plastisols where rapid fusion is required (72). Another important class of materials are the vinyl chloride—vinyl acetate copolymers. Principal producers include Borden Chemicals Plastics, B. F. Goodrich Chemical, and Union Carbide. The copolymerization of vinyl chloride with vinyl acetate yields a material with improved processabihty compared with vinyl chloride homopolymer. However, the physical and chemical properties of the copolymers are different from those of the homopolymer PVC. Generally, as the vinyl acetate content increases, the resin solubiUty in ketone and ester solvents and its susceptibiUty to chemical attack increase, the resin viscosity and heat distortion temperature decrease, and the tensile strength and flexibiUty increase slightly. 

Polyphosphates are also an important class of organophosphorus polymers. In addition to their flame-retardant characteristics, they possess attractive plasticizing properties and can be used as polymeric additives to other polymers [123-128]. In general, polyphosphates can be prepared by interfacial [119,129], melt [130], or solution polycondensation [131,132a,b]. Kricheldorf and Koziel [133] prepared polyphosphates from silylated bisphenols. 

Surfactants used as lubricants are added to polymer resins to improve the flow characteristics of the plastic during processing they also stabilise the cells of polyurethane foams during the foaming process. Surfactants are either nonionic (e.g. fatty amides and alcohols), cationic, anionic (dominating class e.g. alkylbenzene sulfonates), zwitterionic, hetero-element or polymeric (e.g. EO-PO block copolymers). Fluorinated anionic surfactants or super surfactants enable a variety of surfaces normally regarded as difficult to wet. These include PE and PP any product required to wet the surface of these polymers will benefit from inclusion of fluorosurfactants. Surfactants are frequently multicomponent formulations, based on petro- or oleochemicals. 

BFRs are one of the last classes of halogenated compounds that are still being produced worldwide and used in high quantities in many applications. In order to meet fire safety regulations, flame retardants (FRs) are applied to combustible materials such as polymers, plastics, wood, paper, and textiles. Approximately 25% of all FRs contain bromine as the active ingredient. More than 80 different aliphatic, cyclo-aliphatic, aromatic, and polymeric compounds are used as BFRs. BFRs, such as polybrominated biphenyls (PBBs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), and tetrabromobisphenol A (TBBPA), have been used in different consumer products in large quantities, and consequently they were detected in the environment, biota, and even in human samples [26, 27]. 

The main classes of plasticizers for polymeric ISEs are defined by now and comprise lipophilic esters and ethers [90], The regular plasticizer content in polymeric membranes is up to 66% and its influence on the membrane properties cannot be neglected. Compatibility with the membrane polymer is an obvious prerequisite, but other plasticizer parameters must be taken into account, with polarity and lipophilicity as the most important ones. The nature of the plasticizer influences sensor selectivity and detection limits, but often the reasons are not straightforward. The specific solvation of ions by the plasticizer may influence the apparent ion-ionophore complex formation constants, as these may vary in different matrices. Ion-pair formation constants also depend on the solvent polarity, but in polymeric membranes such correlations are rather qualitative. Insufficient plasticizer lipophilicity may cause its leaching, which is especially undesired for in-vivo measurements, for microelectrodes and sensors working under flow conditions. Extension of plasticizer alkyl chains in order to enhance lipophilicity is only a partial problem solution, as it may lead to membrane component incompatibility. The concept of plasticizer-free membranes with active compounds, covalently attached to the polymer, has been intensively studied in recent years [91]. 

In his famous work of 1920 Hermann Staudinger first described the correct structure of polystyrene (10). It was Staudinger, too, who gave polystyrene its name and elucidated the mechanism of its formation (11). The polymerization of styrene provided access to a big class of substances and made a significant contribution to the understanding of natural polymers and to the synthesis of industrial plastics. A whole new branch of the chemical industry is based on the key substance polystyrene. 

Ihe polymers of the 2-cyanoacrylic esters, more commonly known as the alkyl 2-cyanoacrylates, are hard glassy resins that exhibit excellent adhesion to a wide variety of materials. The polymers are spontaneously formed when their liquid precursors or monomers are placed between two closely fitting surfaces. Tile spontaneous polymerization of these very reactive liquids and the excellent adhesion properties of the cured resins combine to make these compounds a unique class of single-component, ambient-temperature-curing adhesive of great versatility (Table 3). The materials that can be bonded run the gamut from metals, plastics, most elastomers, fabrics, and woods to many ceramics. 

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