title: Polymers from fatty acids: poly(ω-hydroxyl tetradecanoic acid) synthesis and physico-mechanical studies.
abstract: This Article describes the synthesis and physicomechanical properties of bioplastics prepared from methyl ω-hydroxytetradecanoic acid (Me-ω-OHC14), a new monomer available by a fermentation process using an engineered Candida tropicalis strain. Melt-condensation experiments were conducted using titanium tetraisopropoxide (Ti[OiPr](4)) as a catalyst in a two-stage polymerization (2 h at 200 °C under N(2), 4 h at 220 °C under 0.1 mmHg). Poly(ω-hydroxytetradecanoate), P(ω-OHC14), M(w), determined by SEC-MALLS, increased from 53K to 110K as the Ti(OiPr)(4) concentration increased from 50 to 300 ppm. By varying the polymerization conditions (catalyst concentration, reaction time, second-stage reaction temperature) a series of P(ω-OHC14) samples were prepared with M(w) values from 53K to 140K. The synthesized polyesters with M(w) ranging from 53K to 140K were subjected to characterization by DSC, TGA, DMTA, and tensile testing. Influences of P(ω-OHC14) molecular weight, melting point, and enthalpies of melting/crystallization on material tensile properties were explored. Cold-drawing tensile tests at room temperature for P(ω-OHC14) with M(w) 53K-78K showed a brittle-to-ductile transition. In contrast, P(ω-OHC14) with M(w) 53K undergoes brittle fracture. Increasing P(ω-OHC14) M(w) above 78K resulted in a strain-hardening phenomena and tough properties with elongation at break ~700% and true tensile strength of ~50 MPa. Comparisons between high density polyethylene and P(ω-OHC14) mechanical and thermal properties as a function of their respective molecular weights are discussed.
authors.affiliation: NSF I/UCRC for Biocatalysis and Bioprocessing of Macromolecules, Department of Chemical and Biological Sciences, Polytechnic Institute of NYU, Six Metrotech Center, Brooklyn, New York 11201, United States.
authors.forename: Chen
authors.initials: C
authors.lastname: Liu
authors.forename: Fei
authors.initials: F
authors.lastname: Liu
authors.forename: Jiali
authors.initials: J
authors.lastname: Cai
authors.forename: Wenchun
authors.initials: W
authors.lastname: Xie
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Long
authors.forename: S Richard
authors.initials: SR
authors.lastname: Turner
authors.forename: Alan
authors.initials: A
authors.lastname: Lyons
authors.forename: Richard A
authors.initials: RA
authors.lastname: Gross
mesh_terms: D001672:Biocompatible Materials / Q000032:analysis / Q000737:chemistry*; D019149:Bioreactors; D041022:Candida tropicalis / Q000235:genetics / Q000378:metabolism*; D003460:Crystallization; D005227:Fatty Acids / Q000378:metabolism*; D005285:Fermentation; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D009227:Myristic Acids / Q000032:analysis / Q000737:chemistry*; D030781:Organisms, Genetically Modified / Q000235:genetics / Q000378:metabolism*; D011091:Polyesters / Q000032:analysis / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013718:Tensile Strength; D013816:Thermodynamics
chemical_list: D001672:Biocompatible Materials; D005227:Fatty Acids; D009227:Myristic Acids; D011091:Polyesters