Injection Molding and Appearance of Cellulose‐Reinforced Composites

Abstract

Composite materials based on an ethylene-acrylic acid (EAA) copolymer and 20 wt% cellulose fibers were compounded by two runs in a twin-screw extruder. The composite material with cellulose fibers (CF) and a reference of unfilled EAA were injection molded into plaques using three different temperature profiles with end zone temperatures of 170 C, 200 C, and 230 C. The injection molded samples were then characterized in terms of their mechanical properties, thermal properties, appearance (color and gloss), and surface topography. The higher processing temperatures resulted in a clear discoloration of the composites, but there was no deterioration in the mechanical performance. The addition of cellulose typically gave a tensile modulus three times higher than that of the unfilled EAA, but the strength and strain at rupture were reduced when fibers were added. The processing temperature had no significant influence on the mechanical properties of the composites. Gloss measurements revealed negligible differences between the samples molded at the different melt temperatures but the surface smoothness was somewhat higher when the melt temperature was increased. In general, addition of the cellulose to the EAA reduced the gloss level and the surface smoothness.

Water‐assisted melt processing of cellulose biocomposites with poly(ε‐caprolactone) or poly(ethylene‐acrylic acid) for the production of carton screw caps

“…When cellulosic materials are processed for long periods of time, at a high-temperature degradation can occur, and this might result in discoloration of the composites. 26 The presence of larger agglomerates in CS micrographs in Figure 4 showed that there is a clear difference between the cryo-fractured surfaces of the PCL-CNC and the EAA7-CNC samples with regard to voids and roughness, regardless of the method of compounding. The CNC aggregates seem to be embedded in the EAA7 with a good adhesion and no pull-out, Figure 4a, c, whereas they appear to be dislodged in the PCL-based samples.…”

Nanocellulose: A Fundamental Material for Science and Technology Applications

“…There are several methods available for the fabrication of nanocomposites. The important methods are in situ polymerization, solvent casting, melt intercalation, extrusion, and injection molding [141][142][143][144]. In the in-situ polymerization method, the monomer is mixed with the nanofiller in the presence of an initiator.…”

Recent Developments in Cellulose Nanomaterial Composites

“…Reproduced with permission. [ 162 ] Copyright 2019, Society of Plastics Engineers, published by John Wiley and Sons. f) Freeze‐dried 3D‐printed CNF hydrogel chair; the scale bar corresponds to 10 mm.…”