Differential scanning calorimetry, gel permeation chromatography and linear rheology measurements of poly(D,L-lactide) (Aldrich 805734)

Differential Scanning Calorimetry (DSC), Gel Permeation Chromatography (GPC) and linear rheology measurements of poly(lactic acid) (PLA) samples.

The sample was purchased from Sigma-Aldrich. The certificate of analysis from the company is included in the directory. The sample is acid-terminated and it is a copolymer including both, L and D monomers of lactic acid. 

The data set includes three directories with the corresponding method.

The DSC measurements were done at University of Cádiz, Spain. The following protocol was used:

1) Ramp 1.00 °C/min to 70.00 °C

2)  Ramp 1.00 °C/min to 25.00 °C

There are two file formats: txt and 001, which can be opened by the TA Instruments’ Universal Analysis program. 

The GPC measurements were done in Instituto de Ciencia y Tecnología de Polímeros (CSIC), Madrid by Laura Pascual Pascual. Equipment: Waters 1525 Binary HP2C Pump, Waters 2414 Refractive Index Detector, Waters 2489 UV/Visible Detector. A solution of LiBr in DMF at 1 g/L was used as eluent. 

Columns: Two columns thermostatted at 50°C, measuring 7.8 x 300 mm. The packing is a divinylbenzene polymer with a 5 μm pore size and a working pH range of 2-12.
1) Waters Styragel® HR 3 DMF (500-30,000 Da), 1000 Å pore size (WAT 044223)
2) Waters Styragel® HR 5 DMF (50,000-40,000,000 Da), 100,000 Å pore size (WAT 054466).
To calibrate the equipment, polymethylmethacrylate standards in DMF (1 g/l LiBr) with a concentration of 4 mg/mL and molecular weights between 2990 and 480,000 Da were used.

The linear rheology measurements, Dynamic Strain Sweep (DSS) and Dynamic Frequency Sweep (DFS), were performed during Petra Bacova's stay at IESL-FORTH in Heraklion, Greece in summer 2024.  

The data are saved in two formats, txt and TAD0X format used in rheometers of TA Instruments. The measurements were performed with ARES rheometer. 

DSS files are labeled as follows: method_Ttemperatureingrades.

DFS files are labelled as follows: method_referencegap_Ttemperatureingrades_maximumstrain

The description of each method, the sample preparation as well as the setting of the reference gap and other parameters is described in the technical note elsewhere. [1]

Data were not corrected for rheometer compliance. 

[1] Bacova, P., & Vlassopoulos, D. (2025). Notes on linear rheological measurements: Sample preparation, Dynamic Strain Sweep, Dynamic Frequency Sweep, Temperature Ramp Test. Zenodo. https://doi.org/10.5281/zenodo.17287461