Synthesis of bio-based polycarbonate via one-step melt polycondensation of isosorbide and dimethyl carbonate by dual site-functionalized ionic liquid catalysts

A synthetic pathway for high molecular weight isosorbide-based polycarbonate was developed via one-step direct melt polycondensation of isosorbide and dimethyl carbonate catalyzed by dual site-functionalized ionic liquids.

Branched PLGA derivatives with tailored drug delivery properties

Despite several shortcomings such as extreme hydrophobicity, low drug capacity, characteristic triphasic drug release pattern with a high burst effect, poly(lactic-co-glycolic acid derivatives are widely used in drug delivery. Most frequent attempts to improve their properties are blending with other polymers or synthesis of block copolymers. We introduce a new class of branched poly(lactic-co-glycolic acid) derivatives as promising biodegradable carriers for prolonged or targeted drug release systems, employed as thin adhesive films, solid dispersions, in situ forming implants or nanoparticles. A series of poly(lactic-co-glycolic acid) derivatives with lower molar mass and star or comb architecture were synthesized by a simple, catalyst free, direct melt polycondensation method not requiring purification of the obtained sterile product by precipitation. Branching monomers used were mannitol, pentaerythritol, dipentaerythritol, tripentaerythritol and polyacrylic acid. The products were characterized by molar mass averages, average branching ratio, rheological and thermal properties.

Synthesis, Characterization and in vitro Antimicrobial, Antioxidant and Anticancer Activity of Random Copolyester Using 1,4-Dithiane-2,5-diol

A random copolyester was prepared by direct melt polycondensation method using 1,4-dithiane-2,5-diol, 1,4-cyclohexane diol and Sebacic acid in the mole ratio 1:1:2 using titanium tetra isopropoxide as catalyst. The synthesized copolyester poly(1,4-dithiane-2,5-diol sebacate–co–1,4-cyclohexane diol sebacate) (PDCSe) was characterized by FT-IR, 1H NMR and 13C NMR to determine the chemical structure, while wide angle XRD, differential scanning spectroscopy and Inherent viscosity were determined to study its physical properties. Further the antioxidant, antimicrobial and anticancer activities of the synthesized copolyester were determined to study its biological property.

1, 4 Dithiane 2, 5 Diol : An Versatile Monomer to Synthesis Aliphatic Random Copolyester with Biomedical Application

This article uses 1, 4-dithiane-2, 5-diol as a monomer to synthesize aliphatic random copolyester (PDDD).PDDD was synthesized by direct melt polycondensation method and characterized by FT-IR and 1H- NMR. The physical properties of PDDD were characterized by X-ray diffraction, differential scanning calorimetry, as well as viscosity and solubility measurements. The anticancer, antioxidant, and antimicrobial activity of PDDD were evaluated to investigate its potential biomedical applications. Generally, good results were obtained. It is evident that the copolyester exhibits favorable and tunable physical, thermal and biological properties and so is a suitable candidate for biomedical applications.

Effect Dehydrants to Increasing Molecular Weight of Condensed Polylactic Acid

The polylactic acid (PLA) was prepared by direct melt polycondensation using lactic acid aqueous solution as raw material. Considering of the difficulty to rule out small molecules of water, magnesium or magnesium methoxide which could react with water were used as dehydrant and added in the PLA polycondensation, respectively. The determination of moisture, GPC and DSC results showed that both the magnesium and magnesium methoxide are effective in dehydration, the molecular weight of final products PLA is significantly improved and the latter is better. Both of them have a good promoting effect on polycondensation reaction to get a higher molecular weight polylactic acid products. For the time of adding magnesium and magnesium methoxide, it is better to add in the late stage of polycondensation reaction rather than early stage. Furthermore, magnesium has a smaller influence on crystallization of PLA, whereas the crystallinity of PLA is greatly reduced after adding magnesium methoxide.

Synthesis of a Biodegradable Material Poly(lactic acid-co-melamine) via Direct Melt Polycondensation

Directly starting fromD,L-lactic acid (LA) and melamine (MA), novel star-shaped biodegradable material poly (lactic acid-co-melamine) [P(LA-co-MA)] as a kind of potential flame retardant is synthesized via melt polycondensation. When the molar feed ration(LA)/n(MA) is 60/1, the optimal synthetic conditions are discussed. After the prepolymerization at 140 °C for 8 h, using 0.4wt% stannous chloride as the catalyst, the melt copolymerization at 160 °C for 8 h gives the copolymer with the biggest intrinsic viscosity 0.87 dLg-1.