Polyolefins–biofibre composites: A new way for an industrial production

Abstract

Low density polyethylene (LDPE) composites based on cellulose fibres have been processed by high shear extrusion with water injection to help dispersion of fibres and release nanofibres from cellulose. Influence of extrusion parameters as shear, residence time, storage conditions of the matrix, and effect of water injection on the morphological properties of the composites have been studied using microscopy. Optimization of the extrusion parameters is necessary to reach a dispersion of the fibres. Increasing shearing forces and residence time allows limiting the presence of large aggregates of cellulose fibres. Use of powdered LDPE, even for short residence time and low shear, is efficient to produce well‐dispersed composites. Injection of water during the extrusion also improves the quality of the dispersion. However, no nanofibres are observed. The main effect is a spectacular decrease of the discoloration (yellowing) due to cellulose degradation. Mechanical properties of the composites have been investigated. Young modulus increases with cellulose content and reinforcing effect is more important above 10% by weight. For well‐dispersed composites, the extrusion parameters have no significant influence on the stiffness of the composites. However, due to the weakness of the interface, the ductility of composites is reduced compared with LDPE. POLYM. ENG. SCI., 47:467–476, 2007. © 2007 Society of Plastics Engineers.

Efficient one-step melt-compounding of copolyetheramide/pristine clay nanocomposites using water-injection as intercalating/exfoliating aid

“…On the contrary, water prevents the matrix from any thermal degradation in the barrel by plasticizing and lubricating the processing medium. This observation has already been reported even though the mechanism is still unclear [52]. Injecting water during extrusion prevents PEBA from thermal degradation and does not lead to the hydrolysis of the polyamide blocks, due to rather slow kinetics and short residence time (less than 30 seconds in contact with water).…”

“…A similar phenomenon is reported in the literature for polymer/cellulose composites prepared with water injection into the melt. Cellulose degradation products responsible for the coloration of the material were steam-extracted and resulting material exhibited a limited coloration [52]. Finally, it is worth noticing that materials exhibiting similar structures detected by XRD and TEM (and limited differences in rheological responses) present different thermomechanical behaviors because of slight changes in the chemical composition (organo-modifiers account for less than 2 wt% of the PEBA/OMMT nanocomposites).…”

Nanofilled and/or toughened POM composites produced by water-mediated melt compounding: Structure and mechanical properties

“…the nanoparticles are already embedded in the polymer which guarantees easy handling and minimized health risk. Water-mediated melt compounding techniques to disperse various nano-and microfillers were already tried for various thermoplastic systems, such as polypropylene and clay [8], low density polyethylene and cellulose [9]. However, the use of latices to produce nanofiller containing masterbatches for subsequent melt compounding has received far less attention up to now [10,11].…”

Characterisation of low-odour emissive polylactide/cellulose fibre biocomposites for car interior

“…Many types of fibres, natural (wood, flax, hemp, kenaf…) or synthetic (glass, carbon, aramide), were associated to petroleum-based polymers and more recently to bio-based plastics [10][11][12][13][14][15][16]. The vegetal fibres are an interesting eco-friendly reinforcement system, as they are annually renewable, lighter, cheaper and less reliant on foreign oil sources than synthetic fibres [17].…”