title: Effect of molecular weight on the physical properties of poly(ethylene brassylate) homopolymers.
abstract: Poly(ethylene brassylate) (PEB) is a biodegradable polyester that nowadays is of particular interest owing to its poly(ε-caprolactone)-like properties (with a Tg at -30°C and a Tm at 70°C) and the low-cost of its monomer. However, it is not simple to achieve high molar masses with conventional catalysts. In this work, high molar mass PEBs, characterized by SEC-MALS, were successfully synthesized using triphenyl bismuth (Ph3Bi) as catalyst. Then, with the aim of evaluating the impact of the molecular weight on the physical properties, several PEBs ranging from 27 to 247kgmol(-1) were prepared. It was demonstrated that above a Mw of 90Kgmol(-1), PEB behaved in a constant manner. PEBs with lower molecular weight (<46Kgmol(-1)) showed lower values of Tg (~(-35°C)) and presented a melting peak that was split into three or four different peaks while their crystallites started to melt earlier (at ~30°C). In addition, these PEBs were more sensitive to thermal degradation (two additional stages of degradation were observed) and, what is more important, were found to be prone to brittle fracture. As the Mw rose, the PEB samples became more ductile and those PEBs with a molecular weight above 90Kgmol(-1) possessed deformation at break values higher than 800%, secant modulus in the 296-324 range and ultimate tensile strength of >20MPa.
authors: Department of Mining-Metallurgy Engineering and Materials Science, POLYMAT, University of the Basque Country (UPV/EHU), School of Engineering, Alameda de Urquijo s/n, Bilbao 48013, Spain. Electronic address: jorge.fernandez@ehu.es.
authors: Jorge
authors: J
authors: Fernández
authors: Department of Mining-Metallurgy Engineering and Materials Science, POLYMAT, University of the Basque Country (UPV/EHU), School of Engineering, Alameda de Urquijo s/n, Bilbao 48013, Spain.
authors: Hegoi
authors: H
authors: Amestoy
authors: POLYMAT, University of the Basque Country (UPV/EHU), Joxe Maria Korta Center, Avenida Tolosa 72, Donostia/San Sebastian 20018, Spain.
authors: Haritz
authors: H
authors: Sardon
authors: POLYMAT, University of the Basque Country (UPV/EHU), Joxe Maria Korta Center, Avenida Tolosa 72, Donostia/San Sebastian 20018, Spain.
authors: Miren
authors: M
authors: Aguirre
authors: SGIker, General Research Services, University of the Basque Country (UPV/EHU), B. Sarriena S/N, Leioa 48940, Spain.
authors: Aitor Larrañaga
authors: AL
authors: Varga
authors: Department of Mining-Metallurgy Engineering and Materials Science, POLYMAT, University of the Basque Country (UPV/EHU), School of Engineering, Alameda de Urquijo s/n, Bilbao 48013, Spain.
authors: Jose-Ramon
authors: JR
authors: Sarasua
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D004988:Ethers, Cyclic / Q000737:chemistry*; D008970:Molecular Weight; D011091:Polyesters
chemical_list: D001672:Biocompatible Materials; D004988:Ethers, Cyclic; D011091:Polyesters; C016240:polycaprolactone; C519611:ethylene brassylate
keywords: Mechanical properties; Molecular weight; Poly(ethylene brassylate); Thermal properties; Triphenyl bismuth