%0 Journal Article
%T Novel Microwave-Assisted Synthesis of Poly(D,L-lactide): The Influence of Monomer/Initiator Molar Ratio on the Product Properties
%A Ljubisa Nikolic
%A Ivan Ristic
%A Borivoj Adnadjevic
%A Vesna Nikolic
%A Jelena Jovanovic
%A Mihajlo Stankovic
%J Sensors
%D 2010
%I MDPI AG
%R 10.3390/s100505063
%X Poly(D,L-lactide) synthesis using tin(II) 2-ethylhexanoate initiated ring-opening polymerization (ROP) takes over 30 hours in bulk at 120 ˇăC. The use of microwave makes the same bulk polymerization process with the same initiator much faster and energy saving, with a reaction time of about 30 minutes at 100 ˇăC. Here, the poly(lactide) synthesis was done in a microwave reactor, using frequency of 2.45 GHz and maximal power of 150 W. The reaction temperature was controlled via infra-red system for in-bulk-measuring, and was maintained at 100 ˇăC. Different molar ratios of monomer and initiator, [M]/[I], of 1,000, 5,000 and 10,000 were used. The achieved average molar masses for the obtained polymers (determined by gel permeation chromatography) were in the interval from 26,700 to 112,500 g/mol. The polydispersion index was from 2.436 to 3.425. For applicative purposes, the obtained material was purified during the procedure of microsphere preparation. Microspheres were obtained by spraying a fine fog of polymer (D,L-lactide) solution in tetrahydrofuran into the water solution of poly(vinyl alcohol) with intensive stirring.
%K poly(D
%K L-lactide)
%K novel microwave synthesis
%K ring-opening polymerization (ROP)
%U http://www.mdpi.com/1424-8220/10/5/5063