Crystallization behavior of α‐cellulose short‐fiber reinforced poly(lactic acid) composites

Abstract

The isothermal crystallization behavior of a-cellulose short-fiber reinforced poly(lactic acid) composites (PLA/a-cellulose) was examined using a differential scanning calorimeter and a petrographic microscope. Incorporating a natural micro-sized cellulose filler increased the spherulite growth rate of the PLA from 3.35 lm/min for neat PLA at 105 C to a maximum of 5.52 lm/min for the 4 wt % PLA/a-cellulose composite at 105 C. In addition, the inclusion of a-cellulose significantly increased the crystallinities of the PLA/a-cellulose composites. The crystallinities for the PLA/a-cellulose composites that crystallized at 125 C were 48-58%, higher than that of the neat PLA for $13.5-37.2%. The Avrami exponent n values for the neat and PLA/a-cellulose composites ranged from 2.50 to 2.81 and from 2.45 to 3.44, respectively, and the crystallization rates K of the PLA/a-cellulose composites were higher than those of the neat PLA. The activation energies of crystallization for the PLA/a-cellulose composites were higher than that of the neat PLA. The inclusion of a-cellulose imparted more nucleating sites to the PLA polymer. Therefore, it was necessary to release additional energy and initiate molecular deposition.

Effects of Compressed CO2 and Cotton Fibers on the Crystallization and Foaming Behaviors of Polylactide

“…This was attributed to the crystal nucleating effect of the cellulose fibers, which can provide more heterogeneous nucleating sites. 51 With a fixed cotton fibers composition, the lower crystallinity of the foamed samples generated a more significant cold crystallization during the first heating process. This agreed with our observation in Figure 3.…”

“…At the same saturation pressure, the X c DSC value improved slightly with increased cotton content. This was attributed to the crystal nucleating effect of the cellulose fibers, which can provide more heterogeneous nucleating sites . With a fixed cotton fibers composition, the lower crystallinity of the foamed samples generated a more significant cold crystallization during the first heating process.…”

Thermoplastic composites of polyamide‐12 reinforced by cellulose nanofibers with cationic surface modification

“…CNFs are also environmentally friendly, safe, and biodegradable . These outstanding characteristics have attracted much attention and hundreds of research papers dealing with CNFs (including nanocrystal) have been published during the last decade . In particular, the automotive industry is interested in finding materials that are lightweight, renewable, and bio‐based and yet also exhibit good mechanical properties.…”

Polyblends and composites of poly (lactic acid) (PLA): a review on the state of the art

“…Also the water absorption of PLA was reduced by 18% due to the incorporation of modified flax fibers. Wu et al [95] prepared α-cellulose short-fiber reinforced PLA composites and investigated the isothermal crystallization behavior of these composites. The crystallinity of the composites was greatly improved due to the presence of cellulose fibers.…”