Chemical modification of chlorinated microbial polyesters.
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.
Arkin
Ali Hakan
AH
Department of Chemistry, Zonguldak Karaelmas University, 67100 Zonguldak, Turkey.
Hazer
Baki
B
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
D002713:Chlorine; D006885:Hydroxybutyrates; D011091:Polyesters; C088151:poly(3-hydroxyoctanoic acid); C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates