Poly repeating unit

Polymer—A large molecule (a macromolecule) made up of many (poly) repeat units (mers). A sample of macromolecules. 

Repeating Unit, poly (repeating unit) % Crystalline T, rc) T , rc)... 

Poly(tetmfluoroethylene). Poly(tetrafluoroethylene) is prepared from tetrafluoroethy-lene and consists of repeating units in a predominantly linear chain ... 

Poly(vinylidene Fluoride). Poly(vinylidene fluoride) consists of linear chains in which the predominant repeating unit is... 

Poly(butylene Terephthalate). Poly(butylene terephthalate) is prepared in a condensation reaction between dimethyl terephthalate and 1,4-butanediol and its repeating unit has the general structure... 

Those polymers which are the condensation product of two different monomers are named by applying the preceding rules to the repeat unit. For example, the polyester formed by the condensation of ethylene glycol and terephthalic acid is called poly(oxyethylene oxyterphthaloyl) according to the lUPAC system, as well as poly (ethylene terephthalate) or polyethylene terephthalate. 

Strauss and Williamst have studied coil dimensions of derivatives of poly(4-vinylpyridine) by light-scattering and viscosity measurements. The derivatives studied were poly(pyridinium) ions quaternized y% with n-dodecyl groups and (1 - y)% with ethyl groups. Experimental coil dimensions extrapolated to 0 conditions and expressed relative to the length of a freely rotating repeat unit are presented here for the molecules in two different environments ... 

It has been observedt that poly(1,1-dimethyl propane) is the product when 3-methylbutene-l is polymerized with AICI3 in ethyl chloride at -130°C. Write structural formulas for the expected repeat units and those observed and propose an explanation. 

Poly(viaylidene fluoride) [24937-79-9] is the addition polymer of 1,1-difluoroethene [73-38-7], commonly known as vinylidene fluoride and abbreviated VDF or VF2. The formula of the repeat unit in the polymer is —CH2—CF2—. The preferred acronym for the polymer is PVDF, but the abbreviation PVF2 is also frequently used. The history and development of poly(vinyhdene fluoride) technology has been reviewed (1 3). 

Poly(l,3,4-oxadia2ole-2,5-diyl-vinylene) and poly(l,3,4-oxadia2ole-2,5-diyl-ethynylene) were synthesi2ed by polycondensation of fumaramide or acetylene-dicarboxamide with hydra2ine sulfate in PPA to study the effect of the two repeating units on polymer electronic and thermal properties (55). 

Polymer Solutions. Perhaps the most extensively studied macromolecular Hquid crystals are the synthetic polypeptides, such as poly( y-benzyl L-glutamate) [25513-40-0] (PBLG). PBLG is a homopolymer of the L-enantiomorph of a single amino acid with the foUowiag repeat unit. 

The ester linkage in the repeating unit characterizes polyesters. R and R represent portions of the monomer molecule that do not participate in the polymerization. They may vary widely, giving rise to many different polyesters. Poly(ethylene terephthalate) (PET), made from ethylene glycol... 

Similarly, the random introduction by copolymerization of stericaHy incompatible repeating unit B into chains of crystalline A reduces the crystalline melting point and degree of crystallinity. If is reduced to T, crystals cannot form. Isotactic polypropylene and linear polyethylene homopolymers are each highly crystalline plastics. However, a random 65% ethylene—35% propylene copolymer of the two, poly(ethylene- (9-prop5lene) is a completely amorphous ethylene—propylene mbber (EPR). On the other hand, block copolymers of the two, poly(ethylene- -prop5iene) of the same overall composition, are highly crystalline. X-ray studies of these materials reveal both the polyethylene lattice and the isotactic polypropylene lattice, as the different blocks crystallize in thek own lattices. 

The Eastman Chemical Company has pubHshed extensively in the patent Hterature (65—74) and the scientific Hterature (75—77) on processes for making poly(phenylene sulfide)- (9-(phenylene disulfide), and related copolymers. The Eastman process involves the reaction of elemental sulfur with Ndiiodobenzene to yield a phenylene sulfide polymer that also contains phenylene disulfide repeating units in the polymer. The fraction of repeating groups containing... 

Mention should be made of the nomenclature for the polymer. Industrially the materially is invariably known in the English-speaking world as polypropylene. However, the lUPAC name for the monomer is propene and until 1975 the recommended lUPAC name was polypropene, a term very rarely used. The latest lUPAC rules base the name of a polymer on the constitutional repeating unit, which in this case is a propylene unit (c.f. a methylene unit for polyethylene) and this leads to the name poly(propylene) (i.e. with brackets). In this volume the more common, unbracketed but still unambiguous name will be used. 

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