Homopolymer definition

CAS 9002-84-0 EINECS/ELINCS 204-126-9 Synonyms Poly (ethylene tetrafluoride) Polytef Polytetrafluoroethene Polytetrafluoroethylene resin PTFE (INCI) Tetrafluoroethene homopolymer Tetrafluoroethylene polymer Tetrafluoroethylene polymers Tetrafluoroethylene resin Classification Thermoplastic homopolymer Definition Polymer of tetrafluoroethylene Emprkal (CiF,),... 

Synonyms Acetic acid, elhenyl ester, homopolymer Acetic acid, vinyl ester, polymer Acetic acid vinyl ester polymers Ethenyl acetate, homopolymer Poly (vinylacetate) Polyvinyl acetate homopolymer Polyvinyl acetate resin PVA PVAc Vinyl acetate homopolymer Vinyl acetate polymer Vinyl acetate resin Classification Homopolymer Definition Homopolymer of vinyl acetate Empirical (C HsOJ,... 

Synonyms a-L-Fucose-1,3-a-D-galactose-1,3-a-D-galacturonic acid homopolymer Definition Fermentation gum derived from sorbitol Uses Skin conditioner, film-former, moisturizer, emulsifier in cosmetics Trade Name Synonyms Fucogel 1000 [Solabia Barnet Prods.] Softbase [Solabia Barnet Prods.]... 

Synonyms Crospolyvidone Crospovidinum Crosslinked PVP 1-Ethenyl-2-pyrrolidinone homopolymer Insoluble polyvidone Insoluble PVP Polyvidonum insoluble, crosslinked Poly(vinyipoiypyrroiidone) Polyvinylpyrrolidone, crossiinked PVPP 2-Pyrrolidinone, 1-ethenyi-, homopolymer 1-Vinyi-2-pyrrolidinone homopolymer Definition Water-insol. synthetic crosslinked homopolymer of N-vinyl-2-pyrrolidinone Empincal (C6HsNO)n... 

Synonyms Acrylic acid homopolymer Acrylic acid polymer Acrylic acid, polymers Acrylic acid resin Acrylic polymer Acrylic polymer resins Acrylic resin Atactic poly(acrylic acid) PAA Polyacrylate Poly (acrylic acid) 2-Propenoic acid, homopolymer Propenoic acid polymer Propenoic acid, polymers, homopolymer Definition Polymer of acrylic acid Empiricai (C3H402)x Formuia [CH2CHCOOH]x Properties M.w. 50,000-250,000 dens. 1.02 kg/l anionic... 

Polydimethylaminoethyl methacrylate Synonyms 2-Methyl-2-propenoic acid, 2-(dimethylamino) ethyl ester, homopolymer 2-Propenoic acid, 2-methyl-, 2-(dimethylamino) ethyl ester, homopolymer Definition Polymer of dimethylaminoethyl methacrylate Empirical (C8HisN02)x Uses Film-former in cosmetics... 

Tetrafluoroethene homopolymer Tetrafluoroethylene polymer Tetrafluoroethylene polymers Tetrafluoroethylene resin Ciassification Thermoplastic homopolymer Definition Polymer of tetrafluoroethylene Empiricai (C2p4)x Formuia [CF2CF2]x, x 20,000 Properties Wh. translucent to opaque solid m.w. 400,000-9,000,000 dens. 2.2 useful temp, range cryogenic to 260 C melts to vise, gel 327 C Shore hardness 55-56 tens. str. 3500-4500 psi elong. 200-300% ( break) chem. inert exc. thermal/chem. resist. lowcoeff. of friction high elec, insulation nonflamm. 

Classification Homopolymer Definition Homopolymer of vinyl acetate Empirical (C4H602)x Formula [CHzCHOOCOCHaJx Properties Water-wh. clear solid resin sol. in benzene, acetone insol. in water dens. 1.191 ref. index 1.4670... 

Just as it is not necessary for polymer chains to be linear, it is also not necessary for all repeat units to be the same. We have already mentioned molecules like proteins where a wide variety of different repeat units are present. Among synthetic polymers, those in which a single kind of repeat unit are involved are called homopolymers, and those containing more than one kind of repeat unit are copolymers. Note that these definitions are based on the repeat unit, not the monomer. An ordinary polyester is not a copolymer, even though two different monomers, acids and alcohols, are its monomers. By contrast, copolymers result when different monomers bond together in the same way to produce a chain in which each kind of monomer retains its respective substituents in the polymer molecule. The unmodified term copolymer is generally used to designate the case where two different repeat units are involved. Where three kinds of repeat units are present, the system is called a terpolymer where there are more than three, the system is called a multicomponent copolymer. The copolymers we discuss in this book will be primarily two-component molecules. We shall discuss copolymers in Chap. 7, so the present remarks are simply for purposes of orientation. 

A polymer blend is a physical or mechanical blend (alloy) of two or more homopolymers or copolymers. Although a polymer blend is not a copolymer according to the above definition, it is mentioned here because of its commercial importance and the frequency with which blends are compared with chemically bonded copolymers. Another technologically significant material relative to the copolymer is the composite, a physical or mechanical combination of a polymer with some unlike material, eg, reinforcing materials such as carbon black, graphite fiber, and glass (see Composite materials). 

Note An alternating copolymer may be considered as a homopolymer derived from an implicit or hypothetical monomer, see Note 1 to Definition 2.4. 

A polymer derived from the polycondensation of a single actual monomer, the molecules of which terminate in two different complementary functional groups (e.g. 6-aminohexanoic acid) is, by definition, a (regular) homopolymer. When two different monomers of this type react together, the product is a copolymer that can be named in appropriate fashion. For example, if 6-aminohexanoic acid is copolycondensed with 7-aminoheptanoic acid, leading to a statistical distribution of monomeric units, the product is named poly[(6-aminohexanoic acid)-stoi-(7-aminoheptanoic acid)]. 

Turning to the low temperature transition of the homopolymer of PHBA at 350 °C, it is generally accepted that the phase below this temperature is orthorhombic and converts to an approximate pseudohexagonal phase with a packing closely related to the orthorhombic phase (see Fig. 6) [27-29]. The fact that a number of the diffraction maxima retain the sharp definition at room temperature pattern combined with the streaking of the 006 line suggests both vertical and horizontal displacements of the chains [29]. As mentioned earlier, Yoon et al. has opted to describe the new phase as a smectic E whereas we prefer to interpret this new phase as a one dimensional plastic crystal where rotational freedom is permitted around the chain axis. This particular question is really a matter of semantics since both interpretations are correct. Perhaps the more important issue is which of these terminologies provides a more descriptive picture as to the nature of the molecular motions of the polymer above the 350 °C transition. As will be seen shortly in the case of the aromatic copolyesters, similar motions can be identified well below the crystal-nematic transition. 

This technique is based on the use of a linear polymer with pendant functional groups that can be activated to initiate the polymerization of a second monomer. Based on this definition, the linear precursor polymer can be considered as a multifunctional macromolecular initiator. The importance of the grafting from technique by cationic polymerization of the second monomer increased considerably with the advent of living cationic polymerization. The advantage is the virtual absence of homopolymer formation via chain transfer to monomer. 

---