From Polyethylene to Polyester: Influence of Ester Groups on the Physical Properties

Abstract

Aliphatic long-chain polyesters (ALCPEs) were synthesized using the ring-opening metathesis copolymerization of ambrettolide and cis-cyclooctene followed by exhaustive hydrogenation, yielding saturated ALCPEs with methylene-toester ratios (M/E) varying from 15 to 223 and ∞ (polyethylene), of which the ester groups were pseudo randomly distributed over the backbone of the polymer. The melting temperature of these ALCPEs showed an inverse proportional trend with respect to the amount of ester groups in the polymer structure, ranging from 132.1 °C (M/E = ∞) to 91.5 °C (M/E = 15), of which the former is comparable to the melting temperature of high-density polyethylene. The crystallinity and the orthorhombic unit cell of the polymers did not significantly change with increasing M/E. Solid-state NMR was used to show the uniform partitioning of the ester groups over the crystalline and amorphous phase. Even though the lamellar thickness showed a decrease with increasing amount of ester groups, this did only partly explain the decrease in melting temperature. The main factor determining the decrease in melting temperature is the inclusion of ester groups in the crystal lattice, which causes the crystal lattice to be less stable.

Dually Actuated Triple Shape Memory Polymers of Cross-Linked Polycyclooctene–Carbon Nanotube/Polyethylene Nanocomposites

“…It can be seen that for the pure PE, there are two strong diffraction peaks at 2θ of 21.5 ° and 23.7 °, which is consistent with the reported values in the literature [61][62][63]. For the pure PCO, there are two strong diffraction peaks at 2θ of 20.2 ° and 23.2 ° and two weak peaks at 21.5 ° and 25.9 °, which are actually consistent with the reported two strong diffraction peaks at 30.0 ° and 34.8 ° and two weak peaks at 31.9 ° and 37.0 ° by using different wavelength of ca.…”

Tuning the thermal properties of poly(ethylene)‐like poly(esters) by copolymerization of ε‐caprolactone with macrolactones, in the presence of a pyridylamidozinc(II) complex

“…34 In the framework of our interest in the ROP of macrolides, we wish to report the achievement of the homo-and copolymerization of 6HDL with ω-PDL and CL in the presence of a pyridylamidozinc(II) complex, which has been recently described by some of us for the copolymerization of CO 2 and epoxides 35 and for the block copolymerization of CL and lactides. 36 The copolymerization of ω-PDL with other lactones, having conventional ring-size, has been already described in the literature 27,[37][38][39][40][41][42][43][44] to give both block and random copolymers. Conversely, the copolymerization of other macrolactones, such as ethylene brassilate, with smaller lactones was also described in the literature.…”

Influence of the Main-Chain Configuration on the Mechanical Properties of Linear Aliphatic Polyesters

“…7 The most profound effect of the inclusion of ester groups is an enthalpic penalty reducing the heat of fusion of the crystal, which simultaneously decreases the melting temperature. 8,9 Nevertheless, the crystallinity remains high (>50%) independent of the amount of ester groups in the backbone of the polymer.Even though there are many reports on the synthesis and thermal properties of ALCPEs, 10−15 a systematic investigation into the influence of the amount and configuration of the ester groups on the mechanical properties has to our knowledge not been performed. Copolymers of ω-pentadecalactone (PDL) and ε-caprolactone (CL) are ideal candidates for such an investigation, since the random copolymers are easily synthesized in large quantities, while the amount of ester groups is readily determined by the ratio of the two monomers copolymerized.…”