Using microcantilever sensors to measure poly(lactic-co-glycolic acid) plasticization by moisture uptake. (February 2018)

• Record Type: Journal Article
• Authors: Alves, Gustavo Marcati A.; Goswami, Sanjukta Bose; Mansano, Ronaldo D.; Boisen, Anja
• Is Part Of: Polymer testing. Volume 65(2018)
• Page Start: 407
• Page End: 413
• Publication Date: 2018-02
• Subjects: Microcantilever -- Thermal analysis -- Plasticization -- Poly(lactic-co-glycolic acid) -- Glass transition; Polymers -- Testing -- Periodicals; Polymères -- Tests -- Périodiques; 620.1920287
• DOI: 10.1016/j.polymertesting.2017.12.017
• Languages: English
• ISSNs: 0142-9418

Abstract

Abstract: Polymeric materials absorb water when exposed to humidity or in contact with aqueous solutions. The polymer and water molecules interact, changing the physicochemical parameters of the material; the most noticeable effect is a decreased glass transition temperature ( T g ), known as plasticization. We used microcantilever sensors to measure the T g versus moisture content in poly(lactic-co-glycolic acid) (PLGA), a biodegradable polymer used in implants and as a drug carrier. We demonstrate a concomitant measurement of the mass absorption and T g using nanograms of material and an inexpensive setup. The standard deviation of T g for this system was 0.025 °C, and the variation in T g with respect to a 1% RH change was clearly resolved. The decrease in the T g of PLGA was linear (R 2 = 0.99) at a rate of 6.03 ± 0.57 °C per mass% of water absorbed. The initial dry T g of PLGA was extrapolated to 41.24 ± 0.07 °C. Highlights: Simultaneous measurement of glass transition and water uptake using nanograms of material. Inexpensive cantilever measurement setup using CD-ROM pickup. Fast equilibration times decrease total measurement time from several days to hours. Tg versus mass of water in polymer agrees with Gordon-Taylor equation.