Synthesis of some novel blends of polylactide with polylactide-b-poly (ethylene glycol) block copolymers

The synthesis of polylactide (PLA)-b-polyethylene glycol (PEG) linear block copolymers and their use in blends with pure-PLA is described. PLA-b-PEG linear block copolymers were obtained by the reaction between poly(ethylene glycol) bis (2-aminopropyl ether) (molecular weight 2000 Dalton) with PLA in the presence of stannous octoate via trans esterification. Molecular weight measurements of the block copolymers indicated that AB and ABA type block copolymers were obtained by controlling the feed ratio in the trans esterification reactions. The copolymers obtained were purified by the fractional precipitation and then characterized by 1H-NMR, FTIR, GPC and DSC techniques. Blends of pure PLA with PLA-b-PEG displayed improved mechanical properties compared to pure PLA. Thermal, mechanical and morphological characterization of the blends were also conducted. © 2012 Taylor and Francis Group, LLC.Fundamental Research Fund of Shandong University: 2011.10.03.01 108T423This work was financially supported by TUBITAK (Grant #108T423) and Zonguldak Karaelmas University Research Fund (2011.10.03.01)

Synthesis and properties of chitosan-modified poly(vinyl butyrate)

Modification of chitosan by grafting of vinyl butyrate was carried out in homogeneous phase using potassium persulfate as redox initator and 1.5% acetic acid as solvent. The percent grafting and grafting efficiency were analysed and the high grafting efficiency up to 94% was observed. The effects of reaction variables such as monomer concentration, initiator concentration, temperature and reaction time were investigated. It was observed that the solubility of chitosan was markedly reduced after grafting with vinyl butyrate. The grafted product is insoluble in common organic solvents as well in dilute organic and inorganic acids. Characterization of the graft copolymers were carried out by using Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Scanning Electron Microscopy (SEM) technics. Characteristic signal of carbonyl group was observed at 1,731 cm-1 which belongs to the poly vinyl butyrate segments in the graft copolymer. The melting transition of the chitosan main chain in the copolymer shifted to 124°C from its original value 101°C. In addition to these, we have also studied topology of the graft copolymer and the SEM micrograph showed continuous homogenous matrix which means there is no phase separation. © Springer Science+Business Media B.V. 2007.2003/102Acknowledgment The authors gratefully acknowledge the financial support provided by the Uludag University Scientific Research Fund through Project 2003/102

Synthesis of Polylactide-b-Poly (Dimethyl Siloxane) Block Copolymers and Their Blends with Pure Polylactide

The synthesis of polylactide (PLA)-b-poly (dimethyl siloxane) (PDMS) linear block copolymers and their use in blends with pure-PLA are described. PLA-b-PDMS linear block copolymers were obtained by the transesterification reaction in chloroform solution between poly(dimethyl siloxane) bis (2-aminopropyl ether) (molecular weight 2,000 Da) with PLA in the presence of stannous octoate. Molecular weights (Mw) of the block copolymers were varied from 53,800 to 63,600 Da while that of pristine PLA was 73,600 Da. The copolymers obtained were purified by fractional precipitation and then characterized by 1 H NMR, FTIR, GPC, viscometry and DSC techniques. Blends of pure PLA with PLA-b-PDMS block copolymers displayed improved elastic properties (elongation up to 140%) compared to pure PLA (elongation ~9%). Thermal, mechanical and morphological characterization of the blends were also conducted. © 2011 Springer Science+Business Media, LLC.Fundamental Research Fund of Shandong UniversityAcknowledgments This work was financially supported by TUBI-TAK and Zonguldak Karaelmas University Research Fund. The Authors thank to Manolya Kukut (in Yusuf Yagci research group) and Amitav Sanyal (Bosphorus University, İstanbul) for GPC analysis of PLDMS-2), e PLA/PLDMS-2 blend (BL-4: 23 wt% of PLDMS-2). Bars shows (-) 1 µm for a, d and e, (-) 0.1 µm for b the Polymers; and to Gülden Albuz (Cilas Kauc¸uk Zonguldak, Turkey) for stres-strain measurements

Diethyl phthalate removal from aqueous phase using poly(EGDMA-MATrp) beads: kinetic, isothermal and thermodynamic studies

<div><p>In this study, poly(ethylene glycol dimethacrylate-N-methacryloyl-l-tryptophan methyl ester) [poly(EGDMA-MATrp)] beads (average diameter = 106–300 µm), which were synthesized by co-polymerizing of N-methacryloyl-l-tryptophan methyl ester (MATrp) with ethylene glycol dimethacrylate (EGDMA), were used for diethyl phthalate (DEP) adsorption. The various factors affecting the adsorption of DEP from aqueous solutions such as pH, initial concentration, contact time and temperature were analysed. Adsorption behaviour of DEP on the poly(EGDMA-MATrp) beads was investigated by varying pH values of solution, contact time, initial concentration and temperature. An optimum adsorption capacity of 590.7 mg/g for DEP was obtained at 25 °C. The present adsorption process obeyed a pseudo-second-order kinetic model. All the isotherm data can be fitted with the Langmuir, Freundlich and Dubinin–Radushkevich isotherm models. Thermodynamic parameters Δ<i>H</i> = 7.745 kJ/mol, Δ<i>S</i> = 81.92 J/K/mol and Δ<i>G</i> = −16.69 kJ/mol to −18.31 kJ/mol with the rise in temperature from 25 °C to 45 °C indicated that the adsorption process was endothermic and spontaneous.</p></div