Syntheses of random PET‐co‐PTTs and some related copolyesters by entropically‐driven ring‐opening polymerizations and by melt blending: Thermal properties and crystallinity

Abstract

A library of random poly(ethylene terephthalate) (PET), poly(trimethylene terephthalate) (PTT), and seven PET-PTT copolymers has been prepared in a high throughput manner by entropically-driven ring-opening polymerizations of the corresponding macrocyclic oligomers. The products have been investigated by differential scanning calorimetry and wide angle X-ray diffraction. They show that the 50:50 copolymer displays a crystalline phase. The same phase can be formed by in situ transesterification when a 50:50 mixture of PET and PTT is melt blended. Poly(butylene terephthalate) (PBT)-PET and PTT-PBT 50:50 copolymers also show crystal phases. V C 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: [995][996][997][998][999][1000][1001][1002][1003][1004][1005] 2011 An alternative synthetic approach to copolyesters is entropically-driven ring-opening polymerization (ED-ROP). [18][19][20] This involves the ring-opening polymerization of macrocycles at high concentrations. Recently, we have developed a novel method for the high throughput (HTP) synthesis of libraries of polyesters. 21

Plasticized and nanofilled poly(lactic acid)‐based cast films: Effect of plasticizer and organoclay on processability and final properties

“…The possibility of transesterification reactions is in agreement with the observed increase in the polydispersion index (Table IV). 20–22…”

Structural investigation of Poly(ethylene terephthalate)/Poly(trimethylene terephthalate) transesterificated blends

“…Conzatti et al [16] showed that at relative short blending time, the blend forms a block copolymer, while, with increasing the time, the block lengths shortened till to form a random copolymer. In the light of these results, the conditions adopted to prepare the C1 sample should produce a copolymer with marked block features.…”

“…Previous works demonstrated that mechanical and thermal conditions adopted in preparing the PET/PTT 50/50 blend induced transesterification reactions between the polyesters to produce a new molecular features based on PET/ PTT copolymer. The ability of the generated copolymer to form crystal is affected by the length of the blocks and by the distribution of the crystallisable segments of different lengths [15,16].…”

“…By controlling the extent of the interchange reactions, tailored block and random copolyesters can be formed with desirable properties. Several examples of transesterification reactions in polyester blends have been reported in literature [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17].…”

“…Transesterification in PTT/ PET blends was evidenced by the variation of thermal and structural properties with composition and preparation modalities [13][14][15]. The melt mixing time played an important role in the evolution of the interchange reactions, determining the production of copolymers with block or random characteristics [16]. Ko et al [17] synthesized a series of poly(ethylene terephthalate-co-trimethylene terephthalate) copolyesters in a random sequence; the copolymer with equal amount of monomers displayed a X-ray pattern different from those of the PET and PTT homopolymers, thus indicating a new crystal form.…”