lactide was synthesized by reverse polymerization of low molecular weight poly(lactic acid) with two different molecular weights:1500 and 2500. two different lactide purification processes such as: recrystallization in ethyl acetate and washing the crude lactide with ether before recrystallization in ethyl acetate were evaluated. it has been demonstrated that increasing the molecular weight of ...

Abstract In this study, poly (L-lactide) (PLLA), (D-lactide) (PDLA), and their blend (stereocomplex; SC) were investigated by terahertz spectroscopy. Absorption spectra obtained for PLLA isothermally crystallized in a temperature range of 80 °C–140 °C, eight characteristic peaks observed the frequency 1–15 THz. No obvious spectral difference between PDLA was observed, indicating that chirality ...

Group 4 metal initiators with a tetradentate bis(phenolato) ligand polymerized meso-lactide efficiently under ring-opening to give syndiotactic polylactide. L-Lactide was converted faster than rac-lactide and meso-lactide.

the effects of magnesium hydroxide and l-lactide dimer as additives on thermal properties and morphology of poly(l-lactide) (plla) films were studied. hence, neat plla films and films containing additives (10% w/w) were prepared in dichloromethane at room temperature via solution casting. to evaluate thermal history on polymer properties, plla films were annealed by different processes. in one ...

In this work, new biodegradable ABCBA type pentablock copolymers with different mole ratio of L-lactide and PPDO-b-PEG-b-PPDO triblock copolymer were synthesized and characterized. In the first step, PPDO-b-PEG-b-PPDO triblock copolymer was synthesized via a ring-opening polymerization of P-DiOxanone (PDO) monomer with Poly (Ethylene Glycol) (P...

Lactide-based polymers have been widely investigated as materials for tissue engineering. However, characteristics such as low flexibility and elongation tend to limit particular applications, although these can be enhanced by adding plasticizers such as trimethylene carbonate (TMC) to the polymer chain of the copolymer poly(L-lactide-co-D,L-lactide) (PLDLA). The aim of this work was to synthes...

The synthesis of chiral aluminum and yttrium alkoxides and their application for lactide polymerization are reported. The complexes (SalBinap)MOR [4, M = Al, R = (i)Pr; 5, M = Y, R = (CH(2))(2)NMe(2)] are synthesized by reacting the ligand (SalBinap)H(2) [2,2'-[(1,1'-binaphthalene)-2,2'-diylbis(nitrilomethylidyne)]bisphenol] with the appropriate metal trisalkoxide. While enantiomerically pure y...

in this work, new biodegradable abcba type pentablock copolymers with different mole ratio of l-lactide and ppdo-b-peg-b-ppdo triblock copolymer were synthesized and characterized. in the first step, ppdo-b-peg-b-ppdo triblock copolymer was synthesized via a ring-opening polymerization of p-dioxanone (pdo) monomer with poly (ethylene glycol) (peg) using stannous octoate (sn(oct)2) as the cataly...

The helium and oxygen gas barrier properties of poly(lactide) were investigated as a function of stereochemistry and crystallinity degree. Poly(L-lactide) and poly(D,L-lactide) films were obtained by extrusion and thermally cold crystallized in either a0or a-crystalline form with increasing crystallinity degree. Annealing of the films at low temperatures yielded to a0-crystals as well as the cr...

Terpolymers of L-lactide, D,L-lactide and trimethylene carbonate (TMC) were synthesized via the ring-opening polymerization reaction for cyclic monomers using stannous octoate as the initiator at a ratio of ~0.05 mol% (monomers/(SnOct) 2 ). Synthesis was done at 130 °C for 48 h. The inclusion of TMC, an aliphatic elastomeric polycarbonate, alongside polymer chain segments containing L-lactide a...