Stress transfer in microfibrillated cellulose reinforced poly(vinyl alcohol) composites

Abstract

Combined homogenization and sonication treatments of micron-sized lyocell fibres were used to generate microfibrillated celluose (MFC) with fibril diameters of ~350 nm. No further reduction in fibril diameter was observed after 30 minutes treatment. Poly(vinyl alcohol) (PVA) composites reinforced with these fibrils were fabricated using solvent casting and physical and mechanical properties were investigated. The presence of MFC in PVA increased the thermal degradation of the polymer. An increase in both the tensile strength and modulus of the composites was observed for up to 3 wt.% of fibrils; beyond this point no significant increases were observed. An estimate of ~39 GPa is made for the fibril modulus based on this increase. Stress-transfer between the polymer resin and the fibrils was investigated using Raman spectroscopy. Stress transfer in the composite is shown to be greater than that of a pure network of fibres, indicating a good fibre-matrix bond.

Crosslinked poly(vinyl alcohol) composite films with cellulose nanocrystals: Mechanical and thermal properties

“…TGA thermograms of nPVA, XPVA, and CNCs are presented in Figure (a). The nPVA thermogram shows three main thermal degradation transition stages, similar to other observations . The initial transition region is found up to 100 °C and is due to water evaporation.…”

“…Moreover, no significant effect of CNCs on T m of the XPVA films could be found. Similar results for T m have been reported for PVA composites with CNCs . It is worth mentioning that the broadened melting peaks of the crosslinked PVA films with CNCs were observed compared to the sharp peak of the nPVA because the ordered association of the PVA molecules was changed by the presence of CNCs and crosslinking .…”

Cross-linked nanocomposite hydrogels based on cellulose nanocrystals and PVA: Mechanical properties and creep recovery

“…Generally, three main transition states can be observed from the neat PVA [23][24][25]. The first transition step is shown up to 100 °C due to the moisture evaporation.…”

Mechanical properties of individual fiber segments of electrospun lignocellulose‐reinforced poly(vinyl alcohol)

“…The elastic modulus of PVA mats containing 10 w/w % LCNF is above 0.50 GPa, exceeding the tensile modulus of neat PVA mats seven times. In previous studies on similar fibrous cellulose‐PVA nanocomposites, the improvement of mechanical properties have been attributed to the reinforcing cellulose particles that have a significantly higher elastic modulus and binds to the polymer through hydrogen bonding whereas the maximum values of elastic modulus have been associated to particle percolation, i.e., the formation of a continuous network of cellulosic particles . A similar mechanism can be proposed in the present case.…”