Polylactide (Polylactic Acid)
Polylactides are polyesters and are biodegradable. The lactic acid that is formed in the hydrolysis serves as nourishment for microorganisms. Ease of degradation is influenced by factors such as the degree of crystallinity and the molecular weight of the polymer. A higher molecular mass results in a higher Temperatura di transizione vetrosaLa transizione vetrosa è una delle più importanti proprietà chimico-fisiche dei materiali amorfi e semi-cristallini, come, ad esempio, vetri, metalli (amorfi), polimeri, ingredienti farmaceutici e alimentari e definisce l’intervallo di temperatura in cui le proprietà meccaniche die materiali variano da duro e fragile a più morbido, malleabile o gommoso.glass transition, a higher Melting Temperatures and EnthalpiesThe enthalpy of fusion of a substance, also known as latent heat, is a measure of the energy input, typically heat, which is necessary to convert a substance from solid to liquid state. The melting point of a substance is the temperature at which it changes state from solid (crystalline) to liquid (isotropic melt).melting temperature, an increase in tensile strength, and a decrease in breaking elongation.
|DSC 204 F1 Phoenix®
|Al, pierced lid
|N2 (50 ml/min)
Polylactic acid showed a glass transition at 63°C in the 1st heating (midpoint, blue) which was overlapped by a RelaxationWhen a constant strain is applied to a rubber compound, the force necessary to maintain that strain is not constant but decreases with time; this behavior is known as stress relaxation. The process responsible for stress relaxation can be physical or chemical, and under normal conditions, both will occur at the same time. relaxation peak as well as a melting peak between approx. 130°C and 180°C (peak temperature 158°C with a preceding shoulder). The following controlled cooling at 10 K/min was too quick for the material to crystallize. Therefore, only a very small melting eff ect at 153°C and a larger glass transition step (with a higher Δcp of 0.57 J/(g·K) compared to 0.22 J/(g·K) in the 1st heating) occurred in the 2nd heating due to the higher percentage of amorphous material.