Copolymer classification/types

TABLE 1. lUPAC Source-Based Copolymer Classification No. Copolymer type Connective Example... 

The A-B type iniferters are more useful than the B-B type for the more efficient synthesis of polymers with controlled structure The functionality of the iniferters can be controlled by changing the number of the A-B bond introduced into an iniferter molecule, for example, B-A-B as the bifunctional iniferter. Detailed classification and application of the iniferters having DC groups are summarized in Table 1. In Eqs. (9)—(11), 6 and 7 serve as the monofunctional iniferters, 9 and 10 as the monofunctional polymeric iniferters, and 8 and 11 as the bifunctional iniferters. Tetrafunctional and polyfunctional iniferters and gel-iniferters are used for the synthesis of star polymers, graft copolymers, and multiblock copolymers, respectively (see Sect. 5). When a polymer implying DC moieties in the main chain is used, a multifunctional polymeric iniferter can be prepared (Eqs. 15 and 16), which is further applied to the synthesis of multiblock copolymers. 

Results from TEM experiments on solutions of a series of poly(styrene)-poly(cinnamoylethyl methacrylate) (PS-PCEMA) diblocks with short PS blocks and long PCEMA blocks have been compared (Tao et al. 1997) to the theories for block copolymer micelles described above. Micelles of type IV in the Zhulina-Birshtein classification (Fig. 3.18) formed in cyclopentane, which is a selective solvent for PCEMA (coronal A block), when the ratio of was... 

Another possibility of classification for systems copolymer/solvent is the selectivity of the solvent35. In a selective solvent for one block, copolymers exhibit, depending upon the respective volumes of the blocks, five types of structures body centered cubic (C), cylindrical hexagonal (H), lamellar (L), inverse cylindrical hexagonal (H), and inverse body centered cubic (C), the matrix being always formed by the component present in larger proportions. In a non-selective solvent, only three types of structures are observed cylindrical and inverse cylindrical structures on one hand, and cubic and inverse cubic structures on the other hand being equivalent. 

According to our earlier classification, the stationary phase can be a solid, a liquid, or a bonded phase. In the latter two cases, the phase must be coated on, or bonded to, particles of a porous solid support. Only a few materials have found widespread use as stationary solid supports they are silica, synthetic polymers such as the styrene-divinylbenzene copolymer, diatomaceous earths, and some polysaccharides. The most common types and uses are given in Table 2. 

Yet another type of classification of polymers is based on the type of repeating unit. A homopolymer has one type of repeat unit. Copolymers are polymers that have more than one type of monomers or repeat units. If the monomers in a copolymer are distributed randomly along the chain, it is called a regular or random copolymer. If, on the other hand, a sequence of one type of monomer is followed by a sequence of another type of monomer, it is called a block copolymer. If the main chain is one type of monomer and the branch chains are of another monomer, it is called a graft copolymer. 

Table 2. Classification of block copolymers according to their interaction type and composition ...

The classification of copolymers according to structural types and the nomenclature for copolymers have been described previously in Chapter 1. The present chapter is primarily concerned with the simultaneous polymerization of two mono-... 

Monomers are only occasionally symmetric the molecular arrangement is the same regardless of which end of the monomer molecule you are looking at. The arrangement of the monomers in a copolymer can be head-to-tail, head-to-head, or tail-to-tail. Since a copolymer consists of at least two types of repeating units, copolymers can be classified based on how these units are arranged along the chain. These classifications include ... 

Another classification of polymers is based on the number of different types of monomers and their distribution along the polymer chain. Thus, polymers are classified as homopolymers, alternating copolymers, random copolymers, block copolymers, and heteropolymers. They are schematically represented in Figure 12.2. Homopolymers are made up of one type of monomeric unit. Well-known examples of synthetic homopolymers are poly(styrene), poly(vinyl alcohol), poly(vinyl chloride), poly (ethylene), poly (ethylene oxide), and so on. Various natural polysaccharides, such as amylose, cellulose, dextran, chitin, and others, belong to this class as well. Copolymers contain two (or a few more) types of monomers that may be... 

There are several means to modify polymer properties, grafting is one of the effective methods. Grafting is a method in which monomers are covalently bonded (modified) onto the polymer backbone [16], as shown in Figure 3.2. Graft copolymers are special type of polymers that come under the classification of branched... 

Vinyl Resins n (1934) According to common chemical nomenclature, all resins and polymers made from monomers containing the vinyl group, H2C=CHX. In the chemical literature, polystyrene, polyolefins, polymethyl methacrylate and many other styrenic, ethenic, and acrylic copolymers are classified as vinyls (Mishra, M. K. M., and Yagci, Y., Handbook of Vinyl Polymerization Marcel Dekker, New York, 1998). In the plastics literature, the above materials are given their own classifications and the term vinyl is restricted to compounds in which X, above, is not H, a hydrocarbon radical, nor an acrylic-type ester. In daily use, the term vinyl plastics refers primarily to Polyvinyl Chloride and its copolymers, and secondarily to the following Polyvinyl Acetal, Polyvinyl Acetate, Polyvinyl Butyral, Polyvinyl Dichloride, Polyvinyl Formal, Polyvinylidene Chloride, Polyisobutylvinyl Ether, and Poly(l-Vinylpyrrolidone). 

Since plastic materials are seldom supplied without the addition of certain additives and fillers, a classification system must be used to avoid confusion. For example, the specification for acetal materials covers three main types of acetal resins homopolymer, copolymer, and terpolyerm. The resin types are subdivided into classes according to the grade descriptions. The group 1, class 1 represents general-purpose homopolymer acetal resin, and group 2, class 3 represents impact modified copolymer acetal resin. Table 1-1 lists the detailed requirements for acetal materials. 

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