Preparation of Polyester PolyMIPEs by Polycondensation of Low-Molecular Weight Polyol and Divinyl Ester Using Microwave Activation

Several stable non-aqueous apolar-in-polar medium internal phase emulsions (MIPEs) containing divinyl adipate and pentaerythritol in the continuous phase are formulated by varying the nature of the hydrocarbon. Polycondensation is then conducted either under conventional heating or microwave irradiation after addition of a commercially available organocatalyst. Solvent elimination and drying lead to the corresponding polyester polyMIPEs. A tremendous morphological difference between materials is observed according to the heating method employed. The particular efficiency of microwave activation in the polycondensation of the continuous phase of a non-aqueous emulsion is discussed.

Fully bio-based aromatic–aliphatic copolyesters: poly(butylene furandicarboxylate-co-succinate)s obtained by ring opening polymerization

Fully bio-based poly(butylene furanoate-co-succinate) copolyesters were synthesized by ring opening polymerization using either organometallic or enzymatic catalysis.

Synthesis of aliphatic polyesters by polycondensation using inorganic acid as catalyst

An effective route for the synthesis of aliphatic polyesters made from adipic or sebacic acid and alkanediols, using inorganic acid as a catalyst is reported. The monomer composition, reaction time, catalyst type, and reaction conditions were optimized to yield polyesters with weight average molecular weights of 23,000 for adipic acid and 85,000 for sebacic acid-based polyesters. The polymers melt at temperatures of 52-65°C and possess melt viscosity in the range of 5600-19,400cP. This route represents an alternative method for producing aliphatic polyesters for possible use in the preparation of degradable disposable medical supplies.

Enhancing the functionality of biobased polyester coating resins through modification with citric acid

Citric acid (CA) was evaluated as a functionality-enhancing monomer in biobased polyesters suitable for coating applications. Model reactions of CA with several primary and secondary alcohols and diols, including the 1,4:3,6-dianhydrohexitols, revealed that titanium(IV) n-butoxide catalyzed esterification reactions involving these compounds proceed at relatively low temperatures, often via anhydride intermediates. Interestingly, the facile anhydride formation from CA at temperatures around CA's melting temperature ( T m = 153 degrees C) proved to be crucial in modifying sterically hindered secondary hydroxyl end groups. OH-functional polyesters were reacted with CA in the melt between 150 and 165 degrees C, yielding slightly branched carboxylic acid functional materials with strongly enhanced functionality. The acid/epoxy curing reaction of the acid-functional polymers was simulated with a monofunctional glycidyl ether. Finally, the CA-modified polyesters were applied as coatings, using conventional cross-linking agents. The formulations showed rapid curing, resulting in chemically and mechanically stable coatings. These results demonstrate that citric acid can be applied in a new way, making use of its anhydride formation to functionalize OH-functional polyesters, which is an important new step toward fully biobased coating systems.