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Inter- and intramolecular interactions in multicomponent polymer systems influence their physical and chemical properties significantly and thus have implications on their synthesis and processing. In the present study, chemical images were obtained by plotting the peak position of a spectral band from the data sets generated using in situ attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopic imaging. This approach was successfully used to visualize changes in intra- and intermolecular interactions in poly(3-hydroxybutyrate)/poly(L -lactic acid) (PHB/PLLA) blends during the isothermal melt crystallization. The peak position of ν(C＝O) band, which reflects the nature of the intermolecular interaction, shows that the intermolecular interactions between PHB and PLLA in the miscible state (1733 cm−1) changes to the inter- and intramolecular interaction (CH3⋯O=C, 1720 cm−1) within PHB crystal during the isothermal melt crystallization. Compared with spectroscopic images obtained by plotting the distribution of absorbance of spectral bands, which reveals the spatial distribution of blend components, the approach of plotting the peak position of a spectral band reflects the spatial distribution of different intra- and intermolecular interactions. With the process of isothermal melt-crystallization, the disappearance of the intermolecular interaction between PHB and PLLA and the appearance of the inter- and intramolecular interactions within the PHB crystal were both visualized through the images based on the observation of the band position. This work shows the potential of using in-situ ATR FT-IR spectroscopic imaging to visualize different types of inter- or intramolecular interactions between polymer molecules or between polymer and other additives in various types of multicomponent polymer systems. Graphical Abstract [ABSTRACT FROM AUTHOR]

Natural fibre-reinforced biopolymer composites are of special interest because they are entirely bioresourced, recyclable and biodegradable. Poly(lactic acid) (PLA), poly(hydroxybutyrate- co -hydroxyvalerate) (PHBV) and poly(butylene succinate) (PBS) are among the most known environment-friendly biodegradable thermoplastics. Unfortunately, they present unbalanced mechanical characteristics when they are taken separately. The aim of this work is to overcome this problem using a blending process accompanied with fibre reinforcement. For this purpose, entirely biodegradable composite materials were fabricated and characterized. These biocomposites are based on two different ternary PLA/PHBV/PBS blends reinforced with twill flax fabrics and fabricated using extrusion and film-stacking techniques. Monotonic and cyclic load–unload tensile tests followed by acoustic emission and scanning electron microscopy observations were performed. In particular, the obtained biocomposites present interesting mechanical properties with a tensile modulus of 20 GPa and an ultimate tensile strength of 110 MPa. [ABSTRACT FROM AUTHOR]