Surface modification of spruce wood flour and effects on the dynamic fragility of PLA/wood composites

Abstract

Poly (lactic acid) (PLA), a biodegradable aliphatic semicrystalline polyester was filled with 40 wt% spruce wood flour (WF), to produce composite materials. Hydrothermal treatment, as well as maleic anhydride, vinyltrimethoxysilane, and stearic acid surface treatments were applied. The influence of surface modifications for WF was tested in terms of thermal, mechanical, and viscoelastic properties. The recorded results show that in both, the untreated and treated PLA/WF composites, the rigid amorphous phase content has been enhanced. The presence of WF causes a stiffness increase of the PLA/WF composites, while damping factor was decreased. The effect of wood surface modifications on interfacial compatibility with PLA was estimated by dynamic fragility parameter m calculated according the Williams‐Landel‐Ferry equation. The incorporation of untreated WF increased dynamic fragility of PLA/WF composites markedly, whereas used silane, maleic anhydride and hydrothermal treatments lead to lower values of parameter m. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers

Characterization of Extruded Poly(lactic acid)/Pecan Nutshell Biocomposites

“…All the biocomposite formulations showed a tan peak at higher temperatures (>50 ∘ C), with the biocomposites formulated with defatted PNSP showing temperatures above 65 ∘ C. This result is indicating that the defatted treatment in the PNSP produced a higher restriction in the molecular mobility of the biocomposites. Similar results were reported by Gregorova et al for the PLA-wood flour composites [21]. Moreover, different investigations of the biocomposites have discussed the effect of rigid fillers in polymeric matrices, which report that the fillers contribute to higher mechanical and thermal losses in the biocomposites [21,35].…”

“…Similar results were reported by Gregorova et al for the PLA-wood flour composites [21]. Moreover, different investigations of the biocomposites have discussed the effect of rigid fillers in polymeric matrices, which report that the fillers contribute to higher mechanical and thermal losses in the biocomposites [21,35].…”

“…An extrusion process is ideal in order to fabricate biocomposites with good homogenization, because this procedure can melt the polymer matrix while being mixed with the particulate filler passing through a screw process. This processing technique has been used since the 1950s, but its application in biocomposites when using biodegradable matrices is recent [21]. In this regard, Tisserat et al discussed the limitations of moisture in the particulate fillers used in the extrusion process and reported that a reduction of the moisture content improves the interaction particle-matrix [22].…”

Processing and characterization of high environmental efficiency composites based on PLA and hazelnut shell flour (HSF) with biobased plasticizers derived from epoxidized linseed oil (ELO)

“…Other successful coupling systems include silane-based coupling agents, alkali soaking, maleic anhydride treatment. All these coupling systems have demonstrated their usefulness in improving PLA-cellulosic particle interactions, with a considerable increase in elongation at break of PLA/cellulosic composites as well as reducing their impact behavior [31][32][33][34][35][36][37]. Other researchers analyzed the effectiveness of acrylic core-shell rubbers, coconut oil, sodium-montmorillonite, ionic liquids, etc.…”

Multicomponent Polymer Composite/Nanocomposite Systems Using Polymer Matrices from Sustainable Renewable Sources

“…However, the moisture resistance of natural fibers in composite structures can be improved through fiber treatments like chemical modifications (Csizmadia et al 2013;Rowell 2012a;Gregorova et al 2011;Bettini et al 2010;Singha et al 2009a, b;Stark and Gardner 2008). These modifications influence the thermal and mechanical properties of resulted composite materials.…”