Effects of acrylic‐based processing aids on processibility, rheology, thermal and structural stability, and mechanical properties of PVC/wood–sawdust composites

Abstract

Methyl methacrylate and ethylacrylate (MMA-co-EA) and methyl methacrylate and butylacrylate (MMA-co-BA) copolymeric processing aids were introduced into poly(vinyl chloride) (PVC)/33.3 wt % wood-sawdust composites containing 0.6 and 2.4 phr of calcium stearate lubricant. The properties of the composites were monitored in terms of processibility, rheology, thermal and structural stability, and mechanical properties. It was found that the mixing torque, wall shear stress, and extrudate swell ratio increased with increasing processing aid content because of increased PVC entanglement. MMA-co-BA (PA20) was found to be more effective than MMA-co-EA (K120 and K130), this being associated with the flexibility of the processing aids, and the dipole-dipole interactions between sawdust particles and polymeric processing aids. The sharkskin characteristic of the composite extrudate at high extrusion rate was moderated by the presence of processing aids. Adding the acrylic-based processing aids and lubricant into PVC/sawdust composites improved the thermal and structural stability of the composites, which were evidenced by an increase in glass transition and decomposition temperatures and a decrease in polyene sequences, respectively. The changes in the mechanical properties of the composites involved a composite homogeneity, which was varied by degree of entanglement and the presence of wood sawdust, and un-reacted processing aids left in the composites.

Shear and elongational flow properties of peroxide‐modified wood/low‐density polyethylene composite melts

“…Rheological properties and processing are found to have significant effect on the properties of WPCs. Consequently, the rheological properties of WPCs have been studied extensively in various aspects, such as fiber content [3], plasticizer [4], wood particle size [5], and coupling agents [6–7]. However, most studies involve shear measurements only.…”

Dynamic Rheological Behavior and Mechanical Properties of PVC/O-POSS Nanocomposites

“…As seen from Figure 1, the balance torque of blends and plastic time decrease with the increasing O-POSS content. In the plasticizing process, the PVC resin broken into primary particles and then turned to much smaller particle until the end of plasticizing process at high temperature and constantly mechanical stirring [16] .…”

Dynamic rheological behavior and mechanical properties of PVC/CPE/MAP–POSS nanocomposites

“…As seen from Figure 2, the balance torque of the nanocomposites and plastic time both decrease with increasing MAP-POSS content. 16 MAP-POSS has a much less volatile, lower viscosity, and an organic/inorganic-hybridized structure. In the plasticizing process, the PVC resin was broken into primary particles and then turned into much smaller particles until the end of plasticizing process at high temperature and constant mechanical stirring.…”

“…In the plasticizing process, the PVC resin was broken into primary particles and then turned into much smaller particles until the end of plasticizing process at high temperature and constant mechanical stirring. 16 MAP-POSS has a much less volatile, lower viscosity, and an organic/inorganic-hybridized structure. In the mixture, the MAP-POSS has a lower melting point, and the MAP-POSS molecule, which is equivalent to nanometer particles, will fill into free volume between PVC and CPE molecule chains.…”