Effect of wood sawdust content on rheological and structural changes, and thermo‐mechanical properties of PVC/sawdust composites

Abstract

The use of untreated sawdust as a filler in poly(vinyl chloride) (PVC) was examined—the effects of sawdust content on structural and thermal changes, and rheological and mechanical properties being of main interest. The results revealed that the torque and die entrance pressure drop values during mixing were independent of sawdust particles up to 23.1 wt%. The extrudate swell monotonically decreased up to 33.3 wt% sawdust content. Smooth wood‐like texture with controllable size of the extrudate could be obtained at a sawdust content greater than 33.3 wt%. Tensile, impact, flexural and hardness properties of the PVC/sawdust composites considerably decreased with up to 16.7 wt% sawdust content before leveling off for higher sawdust loadings. The composites having sawdust higher than 16.7 wt% showed a benefit of cost savings. The decreases in the mechanical properties of PVC with sawdust are explained in association with the presence of moisture, interfacial defects between fibre and polymer, and fibre dispersions in the PVC matrix. Thermal degradations of PVC in PVC/sawdust composites were evidenced by a decrease in decomposition temperature and an increase in polyene sequences, which were caused by Cl cleavage due to strong hydrogen bonds of fibre–PVC molecules. The maximum of tanδ transition and the glass transition temperature were found to improve with sawdust content as a result of re‐formation of hydrogen bonds between the macromolecules of the fibre and the polymer. The overall results in this work suggest that the properties of PVC/sawdust composites were strongly influenced by sawdust content up to 16.7 wt%. Beyond this value the effect of sawdust content on the properties was comparatively small. Copyright © 2003 Society of Chemical Industry

Effect of natural fibers on thermal and mechanical properties of natural fiber polypropylene composites studied by dynamic mechanical analysis

“…In case of wood flour PVC composites, the glass transition temperature was reported independent of moisture content 33 but increasing with wood flour content. 34 Crystallinity also increases the glass transition temperature. There is evidence that transcrystallinity occurs in natural fiber thermoplastic composites due to the nucleating properties of the cellulosic fibers.…”

Effect of Fiber Type and Coupling Treatment on Properties of High-Density Polyethylene/Natural Fiber Composites

“…Thermoplastics such as high-density polyethylene (HDPE) (Herrera-Franco and Valadez-Gonzalez 2004;Panthapulakkal and Sain 2007), low-density polyethylene (LDPE) (Georgopoulos et al 2005), polypropylene (PP) (Karmarkar et al 2007;Lopez et al 2012), poly(vinyl chloride) (PVC) (Shah and Matuana 2005;Sombatsompop et al 2003), poly(lactic acid) (PLA) (Huda et al 2006), polystyrene (PS) (Mansour et al 2006), and some recycled thermoplastics (Jayaraman and Bhattacharyya 2004;Lei et al 2007) have been compounded with natural fibers. Furthermore, some natural fibers such as bagasse (Sheshmani 2013), rice straw (Ashori 2013), palm (Abdullah et al 2012), flax (Bledzki et al 2009), and other agroforestry wastes (Hamid et al 2013) have been used as a reinforcement into thermoplastics.…”

Influence of type and concentration of maleic anhydride grafted polypropylene and impact modifiers on mechanical properties of PP/wood sawdust composites

“…Various thermoplastics, including polyethylene, 1,2 polypropylene (PP), [3][4][5] and poly(vinyl chloride) (PVC), 6,7 have been used for research and development, both on laboratory and industrial scales. Examples of polymer-wood composite products include decking, window and door profiles, automobile paneling, panel inserts, flower pots, and so on, mostly being manufactured through extrusion and injection molding processes.…”