Potentially Biodegradable “Short-Long” Type Diol-Diacid Polyesters with Superior Crystallizability, Tensile Modulus, and Water Vapor Barrier

Abstract

Long-chain aliphatic polyesters are potential biodegradable polymers having PE-like structure and properties. To develop biodegradable long-chain polyesters for practical applications, a series of “short-long” type long-chain polyesters, PEsxy (x = 2–4, 6, y = 10–16), are designed and synthesized from C2–4,6 short-chain α,ω-diols and C10–16 long-chain α,ω-diacids via melt polycondensation. They showed intrinsic viscosity as high as 0.93–1.64 dL/g and PE-like crystal structure, rapid crystallization, and ductile tensile behavior. Their crystallization and melting temperature showed an increasing trend with diacid chain length and a clear odd–even effect. The highest melting temperature reached 94 °C, and the highest tensile strength reached 53 MPa. Chain length-dependent biodegradability in soil and hydrolytic degradation under neutral conditions at 30–60 °C was also observed. In comparison with the widely used biodegradable poly­(butylene adipate-co-terephthalatae) (PBAT) copolyester, these polyesters show comparable tensile strength, ductility, and oxygen barrier performance, but obviously superior and desirable crystallizability, tensile modulus, and water vapor barrier performance.

Crystallization Rate Minima of Poly(ethylene brassylate) at Temperatures Transitioning between Quantized Crystal Thicknesses

“…The peak crystallization and melting temperatures, heat of crystallization (Δ H c ), and total heat of fusion (Δ H m ) are listed in Table . Such multiple melting behavior has been found in many other precision polyethylenes with moieties either inserted in ,,,, or pendant from the backbone ,− at an equidistant number of CH 2 and is often associated with melting of a metastable structure and fast recrystallization into a more stable polymorph. ,, …”

Scale Synthesis of Poly(butylene carbonate-co-terephthalate) and Its Depolymerization–Repolymerization Recycling Process

“…Furthermore, the T g of PBCT 49 was higher than that of PBST 47 and PBAT 47 when aromatic molar ratios were similar. These results illustrated that the increase of the aromatic molar ratio and decrease in the length of flexible aliphatic segments in the repeating units of PBCTs were able to increase the rigidity of chain segments, which would decrease the motility simultaneously. − It is well known that T m is closely related to the regularity of the chain structure . As shown in Table , the X c values were increased with the increase of the aromatic molar ratio because of the symmetry of the benzene ring.…”

Cyclic Polycarbonates by N-Heterocyclic Carbene-Mediated Ring-Expansion Polymerization and Their Selective Depolymerization to Monomers

“…Recycled polymers are much more environmentally friendly than conventional plastic (e.g., polyethylene (PE)). In this regard, polycarbonates and polyesters with long (CH 2 )­n chains can be used as potential alternatives to traditional plastic, − as the long (CH 2 ) n chains enable efficient packing of the crystalline region in polymers, leading to PE-like properties in terms of thermal and mechanical characteristics. , In a recent study, the resemblance of PE by chemically recyclable polycarbonates having long (CH 2 ) n segments was examined through polycondensation of diols and dialkyl carbonates . Apart from the resemblence with PE, cyclic polymers with long alkyl segments in the main chain are attractive to yield preferred properties. − However, a few studies have focused on these properties mainly due to the significant entropic penalty of the cycling polymer chain through a ring-closure strategy. − …”