No abstract

No abstract

Poly (3-hydroxy butyrate) (PHB), cellulose nano crystal (CNC) and a plasticizer (TBC) are mixed together with PLLA with the aim to increase the elongation at break for use in the food packing sector. Spherical (CNC) and fibril nano crystal (CNF) were prepared by hydrolysis of microcrystalline cellulose (MCC) in distilled water, and then stirred using a magnetic stirrer for 15 days and ultrasonic treatment without using any acids as green method. The morphology, thermal, and mechanical properties were studied using POM, DSC, WAXD, SEM and tensile testing, respectively. DSC demonstrated that the addition of PHB, CNC and TBC to PLLA matrix lead to reduce Tg, TCC and Tm than pure PLLA. FT-IR verified that the carbonyl group C=O appeared broad and some peaks in the PLLA composites 5, 6 and 7 shifted from 3.98 × 108 to 4.07 × 108 Hz, at 3.54 × 108 to 3.44 × 108 Hz, at 3.19 × 108 to 3.13 × 108 Hz. Mechanical testing shows that pure PLLA is brittle, and the elongation at break of PLLA composites reaches up to 205%, making it suitable to use in food packaging.

Two semicrystalline poly(3-hydroxybutyrate) (PHB) and polylactic acid (PLLA) blends with and without poly (vinyl acetate) (PVAc) were prepared by dissolving different ratios in hot chloroform at 50 8C to obtain promising alternative biodegradable materials for eliminating plastic waste. The miscibility, crystallization, melting behavior and vibration modes of the prepared samples were characterized by differential scanning calorimetry (DSC), polarized optical microscopy (POM), Fourier transform infrared spectroscopy (FTIR), and wide angle X-ray diffraction (WAXD) techniques. DSC analysis showed that only one crystallization temperature for blends with PVAc (single homogeneous phase) and two crystallization temperatures for blends without PVAc (immiscible blends) were obtained. The POM results indicated that the morphological structures of B 381 , B 551 , and B 831 samples consist of two types of spherulites (fibrils and banded) which created at different crystallization temperatures. The irrelevant interaction between PHB and PLLA structures was detected from FTIR spectra. The addition of PVAc caused an obvious decrease in the peak position of the carboxyl group C¼ ¼O from 1752 to 1724 cm 21 due to dipoledipole interactions. WAXD indicated that the lattice parameters are changed in blends with PVAc and unchanged without PVAc. Our results indicated that, the PVAc can be used as compatibilizer and improved the compatibility between PHB and PLLA. POLYM. ENG.