## 4 Properties
### Thermal Properties
#### 4.1.2 Tga  
TGA is a commonly used technique to characterize the thermal stability and decomposition pattern of materials under various conditions and to detect the occurring physicochemical processes by measuring the weight changes as a function of temperature. In APs, TGA can be employed to investigate the effect of copolymerization and nanoparticle presence and content on the polymer matrix. Furthermore, important information on sample processability can be gained. In particular, two main data should be taken into consideration: the thermal decomposition temperatures and the residual mass (usually measured under nitrogen atmosphere at 600 \({}^{\circ}\)C). At this temperature, the macromolecular backbone is completely degraded, hence the residual mass can be ascribed only to the presence of nanofillers. Furthermore, by performing more replicates, the standard deviation error in the residual mass can give information on filler dispersion, i.e., nanocomposite homogeneity. Thermal stability of block and random copolymers is usually comprised between that of the parent homopolymers, and it slightly varies with the molar composition [51; 76]. On the other hand, thermogravimetric analysis performed on numerous APs-based nanocomposites demonstrated the beneficial influence of nanoparticles, which are responsible of an improvement of the thermal stability, that is, higher thermal degradation onset. This effect is particularly important for APs that display not excellent thermal resistance, such as PLA [83]. On the contrary, other APs, such as PBS and PBCE, show thermal stability well above 300 \({}^{\circ}\)C; in the latter case even superior to the corresponding aromatic polyester, i.e., poly(butylene therephthalate) (PBT) [73]. Different works have analyzed the thermal stability of PLA containing carbon-based nanomaterials (CBN), and an increase in the degradation temperatures has been ascribed. This effect has been correlated to different factors: (a) good dispersion and compatibility between polymer and fillers, leading to PLA restricted chain motions which can retard degradation; (b) formation of a crystallization layer on nanocomposite surface capable of absorbing some of the heat supplied during TGA experiments; and (c) CBN can create a \"tortuous path\" which delays oxygen permeation and out-diffusion of volatile decomposition products [79]. The introduction of nanosilica in PLA matrix also permitted to increase the polymer thermal stability, making the nanocomposite processable [81]. The addition of montmorillonite to poly(3-hydroxybutyrate-_co-_3-hydroxyvalerate) (PHBV) resulted in an intercalated structural morphology with improved thermal stability, as it supplied an effective oxygen permeation barrier [84]. In another study, scaffolds loaded with cellulose nanocrystals (CNC) and reduced graphene oxide (rGO) showed an increased thermal stability as compared to neat PLA. The addition of both fillers generated a synergistic action [85]. On the other hand, recent work demonstrated that cellulose nanocrystals did not have any influence on the thermal decomposition of PBS and PBS-based copolymers [14], as well as that SWCNTs did not affect the degradation behavior of PBCE and PBCE-based copolymers at low weight content [13].