Effect of cellulose nanocrystals on the crystallization behavior and enzymatic degradation of poly(butylene adipate).

Cellulose nanocrystals (CNCs) are nature-resourced nanoparticles and have been widely used to improve performance of biodegradable polyesters. Two types of CNCs respectively prepared by sulphuric acid hydrolysis (aCNCs) and ammonium persulfate oxidation (oCNCs) processes were incorporated into poly(butylene adipate) (PBA) matrix to regulate its crystallization behavior and enzymatic degradation performance. Thermal and X-ray diffraction analysis revealed that both aCNCs and oCNCs could promote the crystallization ability and lamellar thickening of α-form PBA, while oCNCs showed stronger promotion than aCNCs.

Investigation of Structure and Crystallization Behavior of Poly(butylene succinate) by Fourier Transform Infrared Spectroscopy.

The detailed structure and crystallization behavior of poly(butylene succinate) (PBS) have been investigated by Fourier transform infrared (FTIR) and other methods systematically. For the first time, we confirmed that the C═O stretching modes of PBS can respond to three distinguish absorption bands in the FTIR spectrum, at around 1736, 1720, and 1714 cm respectively. The 1736 cm band is adopted as the stretching mode of C═O groups in free amorphous fraction (MAF); the 1714 cm band which is relevant to more stable structure, displays more anisotropic in polarized FTIR spectra, and has been confirmed as stretching vibrations of hydrogen-bonded C═O groups in the crystalline phase.

Characterizing the Structure and Phase Transformation of Poly(ethylene Oxide)-Urea Complexes Using Terahertz Time-Domain Spectroscopy.

Terahertz time-domain spectroscopy (THz-TDS) was employed to characterize the structure and α→β phase transformation of poly(ethylene oxide) (PEO)-urea complexes. While the THz responses of α- and β-form complexes are both originated from hydrogen bonding interactions, they possess different THz absorption bands. The α-form PEO-urea complex shows two bands at 1.