Poly(ether esters) from pivalolactone, alkanediols, and dimethyl terephthalate. 2. Synthesis and characterization

Abstract

Thermal properties of poly(ether ester)s prepared from pivalolactone (PVL), a homologous series of alkanediols (nG), and dimethyl terephthalate via a two-stage melt process were studied. Both the melting and crystallization temperatures of the poly(ether ester)s decreased with increasing length of the alkanediol used. An odd/even effect was observed, which was explained by assuming a planar zigzag structure. Furthermore, it was shown that the structure of the poly(ether ester)s could be described as consisting of crystalline alkylene terephthalate sequences, responsible for the melting behavior, and amorphous nG-PVL units. A Mark-Houwink equation was determined from viscometric data and from the molecular weights of the poly(ether ester)s. It was found that copolymers with molecular weights M" > 10 000 can be prepared by performing the polycondensation step at 275°C for 2.5 h or by applying a postcondensation. Furthermore, upscaling of the process could be carried out from 25 to 1000 g. The poly(ether ester)s were thermally stable up to 280°C and showed a melting behavior dependent upon the alkylene terephthalate block length.

Polyesters

“…Aromatic-aliphatic polyesters with even numbers of methylene groups melt at higher Repeating-Unit temperature than odd-numbered ones. This odd-even effect has been reported for a number of polyesters 4 and copolyesters 67,68 as well for many other stepgrowth polymers. 69,70 It is generally assigned to variations in the planar zigzag packing of polymer chains.…”

Poly(ether esters) from pivalolactone, alkanediols, and dimethyl terephthalate. 1. Synthesis, structure analysis, and reaction mechanism

“…These results as well as the effect of the composition of the copolymers on the properties will be discussed in more detail in a forthcoming paper. 15 The influence of the catalyst on the synthesis of the copolymers from PVL, alkanediols, and DMT was also studied (see Table I). In one run (exp.…”

“…(The properties of the copolymers will be discussed in a forthcoming paper. 15) In this paper, results are presented of processes carried out in the molten state for the synthesis of copolymers from PVL, alkanediols, and DMT, i.e., with R = CH3 and R' = (CH2)" (Scheme I). In these syntheses x mol of PVL, y mol of DMT, and 2y mol of alkanediol were reacted in the melt in the presence of tetrabutylorthotitanate as a catalyst.…”

Effects of Poly(Ethylene Glycol) Segment on Physical and Chemical Properties of Poly(Ether Ester) Elastomers

“…All the chemicals not mentioned were purchased from Sinopharm Chemical Reagent Co. (Beijing, China) and used as received. Preparation of PET-PEG based poly(ether ester)s. Poly(ether ester)s were synthesized by catalzying two-step reactions involving transesterification and polycondenzation in the melt status under the optimal conditions [20,21]. The synthesis was carried out in a 5L reactor and the representative polymerization procedure was operated as follows: PTA and EG with the feed molar ratio of 1:1.25 were added into the reactor where the catalyst (Sb 2 EG 3 ) and thermal stabilizer (Triphenyl phosphate) were supplemented simultaneously.…”