Graft copolymers, alternating copolymer

The present chapter is primarily concerned with the simultaneous polymerization of two monomers to produce random, statistical, and alternating copolymers. Graft copolymers and block copolymers are not synthesized by the simultaneous polymerization of two monomers. These are generally... 

XXXI. Alternating Copolymer Graft Copolymers VI. Synthesis in the Absence and Presence of Complexing Agents... 

The radical-catalyzed copolymerization of isoprene and maleic anhydride in the presence of polystyrene gives the corresponding alternating copolymer graft copolymer (Table IX). Similar results are obtained with other dienes and appropriate substrate polymers. 

Alternating copolymer graft copolymers are also produced when comonomers that yield alternating copolymers with but not without a complexing agent are copolymerized in the presence of a complexing agent and a suitable polymer, either with or without a free-radical precursor (14). 

The results in Table XIV were obtained by adding an aqueous zinc chloride solution to a poly (butyl acrylate) latex. After precomplexation at 30°C, the monomer mixture and the redox catalyst were added, and the polymerization was carried out at 30°C. Because of the heterogeneity of the reaction mitxure, a large amount of alternating copolymer accompanied the alternating copolymer graft copolymer. 

Similarly, an alternating copolymer containing complexed complexing agent may be prepared from a comonomer mixture and then mixed with different comonomers to form an alternating copolymer graft copolymer. 

A polymer resulting from polymerisation of two or more different monomers i.e., ter-polymer, tetra-polymer for two- and three monomers, respectively. (see also RANDON COPOLYMER, ALTERNATING COPOLYMER, GRAFT COPOLYMER, BLOCK COPOLYMER.)... 

A homopolymer consists of only one type of constitutional repeating unit (A). A copolymer, on the other hand, consists of two or more constitutional repeating units (A, B, etc). Several classes of copolymer are possible block copolymers, alternating copolymers, graft copolymers and statistical copolymers (Fig. 1.10). 

Gaylord, N. G. and Anand, L.C. (1971). Alternating Copolymer Graft Copolymers. III. Cellulose Graft Copolymers. I. Grafting of Alternating Styrene-Acrylonitrile Copolymers onto Cellulose in Presence of Zink Chloride. J. Polym. Scl Part B Polym. Phys., 9,617—621. 

Other copolymer forms are alternating copolymers, block copolymers and graft polymers. 

Polymer Blends, Statistical and Alternating Copolymers, Graft and Block Copolymers. 147... 

Copolymers may be described as alternating copolymers, block copolymers or graft copolymers. The molecular architecture of copolymers may, however, be more complicated than represented in Fig. 8.1. Homopolymers can be linear, star or branched (Fig. 8.2), giving rise to so-called star block copolymers defined by the number of arms (n). 

In their structure the copolymers may contain the monomeric units randomly, and their overall composition is determined by the composition of the initial feed mixture of monomers (see Section 2.3). Alternating copolymers (a//-copolymers) also are known, where the monomers alternate regularly along the chain. Other types include block polymers where a linear arrangement of groups of one type of monomers is present, graft polymers that have side chain blocks connected to a polymer main chain, per-copolymers where ordered sequences of more than two units are present, etc. 

Random Copolymers Alternating Copolymers Graft Polymers Block Copolymers... 

Alternating copolymer Random copolymer Block copolymer Graft copolymer... 

Theoretical models for other systems, such as star, branched, and ring polymers, random and alternating copolymers, graft and block copolymers are discussed in the book by Mattice and Suter [1]. Block copolymers are discussed in Chap. 32 of this Handbook [2]. Theories of branched and ring polymers are presented in the book by Yamakawa [3]. Liquid-crystalline polymers are discussed in the book by Grosberg and Khokhlov [4], and liquid crystalline elastomers in the recent book of Warner and Terentjev [5]. Bimodal networks are discussed by Mark and Erman [6,7]. Molecular theories of filled polymer networks are presented by Kloczkowski, Sharaf and Mark [8] and recently by Sharaf and Mark [9]. 

The first case concerns particles with polymer chains attached to their surfaces. This can be done using chemically (end-)grafted chains, as is often done in the study of model colloids. Alternatively, a block copolymer can be used, of which one of the blocks (the anchor group) adsorbs strongly to the particles. The polymer chains may vary from short alkane chains to high molecular weight polymers (see also section C2.6.2). The interactions between such... 

Moreover, commercially available triblock copolymers designed to be thermoplastic elastomers, not compatihilizers, are often used in Heu of the more appealing diblock materials. Since the mid-1980s, the generation of block or graft copolymers in situ during blend preparation (158,168—176), called reactive compatibilization, has emerged as an alternative approach and has received considerable commercial attention. 

Figure 2.16. (a) Random copolymer, (b) alternating copolymer, (c) block copolymer, (d) graft... 

The epoxy-acrylic resin referred to above is a graft copolymer prepared by the polymerisation of acrylic monomers in the presence of the epoxy resin in such a way that grafting of the acrylic onto the epoxy takes place. Water dispersibility is achieved by neutralising carboxyl groups in the acrylic polymer chain with ammonia or amine. Amino or phenolic resins are used as crosslinkers. Alternatively, solvent-borne epoxy-amino or epoxy-phenolic lacquers can be used. 

Two other forms of copolymers that can be prepared under certain conditions are called block copolymers and graft copolymers. Block copolymers are those in which different blocks of identical monomer units alternate with each other graft copolymers are those in which homopolymer branches of one monomer unit are "grafted" onto a homopolymer chain of another monomer unit. 

When the same monomer is used to build up a polymer, it is termed a homopolymer. Copolymers have two different monomers or functional groups, and terpolymers have three groups. There are even tetrapolymers available. These polymers may be further classified, for example, as random, graft, or block copolymers. Block copolymers, which have alternating sections of specific molecular chains, are used in BW formulations (but are more commonly found in CW programs). 

---