Crystallization and Melting Behavior of Polylactides

Abstract

Six polylactides, polymerized with Salen−Al−OCH3 initiator and having optical purities between 43% and 100%, were analyzed by differential scanning calorimetry, X-ray diffraction, and optical microscopy, following various crystallization conditions. It was found that each of those polylactides can crystallize, even those with low optical purities; their crystallization rate is, however, slower than those for high optical purity polyesters. Moreover, the low optical purity polymers tend to form stereocomplexes between the l and d sequences of the same polylactide, which behavior is ascribed to their multiblock microstructure. A correlation was found between the measured melting temperature of optically active polylactides and their average sequence length.

Electrospun scaffolds of polylactide with a different enantiomeric content and loaded with anti-inflammatory and antibacterial drugs

“…Determined by considering an estimated melting enthalpy of 106 J·g -1 for a 100% crystalline sample. 39,40 Left and right values correspond to crystallinities deduced for the as electrospun material (i.e., considering ΔH m -ΔH c as the enthalpy associated to crystalline phase of the electrospun sample) and those attained after cold crystallization (i.e., considering ΔH m as the enthalpy associated to the final crystalline phase), respectively. of TCS and KTP from PLA 2002D scaffolds after 8 h of exposure to PBS medium rose to 40% and 30%, respectively (Figure 6(a)), while these percentages decreased to 30% and 5% for a similar exposure time when PLA 4032D scaffolds were employed (Figure 6(c)).…”

The Formation and Characterization of Nanocrystalline Phases by Mechanical Milling of Biphasic Calcium Phosphate/Poly-L-Lactide Biocomposite

“…30) Apart from certain similarities, DSC curves shown in Fig. 3 have significantly different shapes, positions, and peak areas compared to the molten BCP/PLLA composite biomaterial, which is the result of structural changes in the phase of PLLA caused by mechanical milling.…”

“…34) The theoretical value of the melting enthalpy for completely crystalline PLLA is 93.7 J/g. 12,[30][31][32][33] The enthalpy of crystallization is proportional to the quantity of the crystalline part in the sample. A decrease in (ÁHc) corresponded to an increase in small and imperfect crystals.…”

Effects of L-lactic acid and D,L-lactic acid on viability and osteogenic differentiation of mesenchymal stem cells

“…These materials exhibit advantages such as good processibility [6][7][8][9] and tunable degradability [9][10][11][12][13]. That is why polyesters have been studied for a long time [14][15][16][17][18][19][20].…”