Poly never synthesized

The word "polymer" (first proposed by Berzelius in 1833) is made of "poly" from the ancient Greek word "mlvq" meaning "many" and "pepot " meaning "part". Polymers are molecules built up from numerous identical chemical "units" spatially repeated to form a chain. From the early times and still nowadays, a distinction is often made between "natural" and "synthetic" polymers, but it is somewhat artificial as natural polymers can now sometimes be synthesized (e.g., synthetic "natural rubber") and some synthetic polymers, which are never found in nature, can be synthesized by natural ways (enzymatic syntheses). 

PREPARATIVE TECHNIQUE H-H polystyrene has never been obtained directly from styrene monomer. It is synthesized by the selective hydrogenation of l,4-poly(2,3-diphenyl-1,3-butadiene) (PDPB) using potassium/ethanol. PDPB is prepared by the free radical polymerization of 2,3-diphenyl-l,3-butadiene to give a 45% cis, 55% trans structure. H-H PS is then given in the Scune ratio of erythro and threo linkages after the chemical reduction of the internal double bond of the PDPB. ... 

PolyCtrimethylene terephthalate) (PTT, also abbreviated as 3GT) is an aromatic polyester made by the melt poly condensation of 1,3-propanediol (PDO) with either terephthalic acid (TPA) or dimethyl terephthalate (DMT). Although available commercially only since 1998, it was one of the three polyesters first synthesized by Whinfield and Dickson (1) in 1941. Two of which, the so-called even-munhered polyCethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT) for the number of methylene units in their chemical structures, are well-estabhshed high volume polymers. However, the odd-numbered PTT remained an obscure polymer. It was never commercialized until recently because PDO was very expensive and was available only as a small volume line chemical. 

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