title: Chemical modification of chlorinated microbial polyesters.
abstract: Chlorination of microbial polyesters poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxyoctanoate) (PHO) was carried out by passing chlorine gas through their solutions. The chlorine contents in chlorinated PHB (PHB-Cl) and chlorinated PHO (PHO-Cl) were between 5.45 and 23.81 wt % and 28.09 and 39.09 wt %, respectively. Molecular weights of the chlorinated samples were in the range of between one-half to one-fourth of the original values because of hydrolysis during the chlorination process. Thermal properties of the PHO-Cl were dramatically changed with an increase in its glass transition (T(g) = 2 degrees C) and the melting transition (T(m)). The T(g) of PHB-Cl varied from -20 to 10 degrees C, and its T(m) decreased to 148 degrees C. The chlorinated poly(3-hydroxyalkanoate)s (PHA-Cl) were converted to their corresponding quaternary ammonium salts (PHA-N(+)R(3)), sodium sulfate salts (PHA-S), and phenyl derivatives (PHA-Ph). Cross-linked polymers were also formed by a Friedel-Crafts reaction between benzene and PHA-Cl. The modified PHO derivatives were characterized by (1)H NMR and (13)C NMR spectrometry, Fourier transform infrared spectroscopy, gel permeation chromatography, and differential scanning calorimetry techniques.
authors.affiliation: Department of Chemistry, Zonguldak Karaelmas University, 67100 Zonguldak, Turkey.
authors.forename: Ali Hakan
authors.initials: AH
authors.lastname: Arkin
authors.forename: Baki
authors.initials: B
authors.lastname: Hazer
mesh_terms: D002713:Chlorine / Q000737:chemistry*; D006885:Hydroxybutyrates / Q000737:chemistry; D015394:Molecular Structure; D011091:Polyesters / Q000138:chemical synthesis* / Q000737:chemistry; D013057:Spectrum Analysis; D013696:Temperature; D000094122:Polyhydroxybutyrates
chemical_list: D002713:Chlorine; D006885:Hydroxybutyrates; D011091:Polyesters; C088151:poly(3-hydroxyoctanoic acid); C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates