Thermoplastic starch (TPS) consisting of corn starch and glycerol as a plasticizer, and TPS-montmorillonite (MMT) nanocomposite were stored at room temperature in the air with relative humidities (RH) of 11, 55 and 85% for seven weeks. Mechanical testing and dynamic mechanical thermal analysis (DMTA) were performed to detect changes in their mechanical properties. Solid-state NMR spectroscopy monitoring the changes in molecular mobility in the samples provided an insight into relations between mechanical properties and local structure. The results of mechanical testing indicated that the addition of MMT results in the increase in the tensile strength and Young’s modulus while elongation at break decreased, indicating the reinforcing effect of MMT. DMTA experiments revealed a decrease in glass transition temperature of starch-rich phase below room temperature for samples stored at higher RH (55 and 85%). This indicates that absorbed water molecules had additional plasticizing effect on starch resulting in higher mobility of starch chain segments. Recrystallization in these samples was deduced from the shape of cross-polarization magic-angle spinning ¹³C NMR spectra. The shape of broad-line ¹H NMR spectra reflected changes in molecular mobility in the studied samples during seven weeks of storage and revealed that a high amount of water molecules impacts the starch intermolecular hydrogen bond density.

Broad line ¹H and ¹³C CP MAS NMR spectra were used to characterize molecular motion and structure in two sets of poly(butylene-adipate-co-terephthalate) (PBAT) / thermoplastic starch (TPS) blends with weight ratios 70:30, 50:50 and 30:70. One set was prepared using a twin-screw extruder, and the second underwent additional mixing. The measured spectra show that ¹H-¹³C polarization transfer was less efficient in the TPS component in mixed blends, indicating enhanced molecular motion of TPS chains. In contrast, polarization transfer was more efficient in PBAT methylene groups, indicating that motion constraints were present in PBAT due to mixing. Structural information was obtained from the deconvolution of ¹H BL NMR spectra and the calculated second moment of their broad components. The results obtained show that blend components affected each other’s mobility more distinctly in blends prepared with additional mixing, in which the domain size of the minor blend component is expected to be smaller and the amount of interphase to be larger.

The paper focuses on the problem of control of accuracy of forming elastic-deformable shafts with low rigidity. In particular, results of analysis of basic factors affecting the accuracy of machining of low-rigidity shafts such as the...

Blends of copolyester poly(butylene adipate-co-terephthalate) (PBAT) with thermoplastic starch (TPS) were prepared by melt mixing and the interactions between p Blends of copolyester poly(butylene adipate-co-terephthalate) (PBAT) with thermoplastic starch (TPS) were prepared by melt mixing and the interactions between p