A Review of Rubber Biocomposites Reinforced with Lignocellulosic Fillers

Lignocellulosic fillers have attracted considerable attention over the years as a promising alternative to conventional petroleum-based fillers (carbon black) in rubber composites due to their renewability, biodegradability, availability, high mechanical properties, low density and low cost. Based on the literature available, a comprehensive review is presented here of rubber biocomposites reinforced with plant-based fillers. The study is divided into different sections depending on the matrix (natural or synthetic rubber) and the type of lignocellulosic fillers (natural fiber, microcrystalline cellulose, lignin and nanocellulose). This review focuses on the curing characteristics, mechanical properties and dynamic mechanical properties of the resulting rubber biocomposites. In addition, the effect of hybrid filler systems, lignocellulosic filler surface modification and modification of the rubber matrix on the properties of these rubber biocomposites are presented and compared. A conclusion is finally presented with some openings for future works.

Recent Developments in Nanocellulose-Reinforced Rubber Matrix Composites: A Review

Research and development of nanocellulose and nanocellulose-reinforced composite materials have garnered substantial interest in recent years. This is greatly attributed to its unique functionalities and properties, such as being renewable, sustainable, possessing high mechanical strengths, having low weight and cost. This review aims to highlight recent developments in incorporating nanocellulose into rubber matrices as a reinforcing filler material. It encompasses an introduction to natural and synthetic rubbers as a commodity at large and conventional fillers used today in rubber processing, such as carbon black and silica. Subsequently, different types of nanocellulose would be addressed, including its common sources, dimensions, and mechanical properties, followed by recent isolation techniques of nanocellulose from its resource and application in rubber reinforcement. The review also gathers recent studies and qualitative findings on the incorporation of a myriad of nanocellulose variants into various types of rubber matrices with the main goal of enhancing its mechanical integrity and potentially phasing out conventional rubber fillers. The mechanism of reinforcement and mechanical behaviors of these nanocomposites are highlighted. This article concludes with potential industrial applications of nanocellulose-reinforced rubber composites and the way forward with this technology.

REINFORCEMENT OF RUBBER BY CARBON BLACK AND LIGNIN-COATED NANOCELLULOSE FIBRILS

The reinforcement of rubber by a co-filler system of carbon black and lignin-coated nanocellulose fibrils (LCNF) is investigated. Natural rubber (NR)–polybutadiene (BR) blend compounds containing LCNF loadings of up to 20% of the total filler package are prepared, and the dispersion state of the LCNF is determined using interferometric and electron microscopy. The LCNF is found to be well dispersed on macro- and micro-dispersion length scales, with discrete fibrils tending to align in the milling/calendering grain direction. Cure properties—scorch, rate, and total yield of crosslinks—are unaffected by the presence of LCNF in the compounds. Tensile to break and cyclic tensile properties are found to be reasonably consistent with those of a conventional all carbon black control compound. Tear and laboratory abrasion resistance properties are maintained versus the control compound, while a systematic and substantial reduction in compound Payne Effect with increasing LCNF content is observed. Basic aging properties of the compounds are unaffected by the presence of LCNF. The potential benefits of LCNF as a lightweight, sustainable, and bio-derived reinforcing filler are outlined.

A review on nanocellulose as a lightweight filler of polyolefin composites

Nanocellulose (NC) possesses low density, high aspect ratio, impressive mechanical properties, nanoscale dimensions, which shows huge potential applications as a reinforced filler. Polyolefin (PO), represented by polyethylene (PE) and polypropylene (PP), has been widely used in industries. Recently nanocellulose/polyolefin nanocomposites (NC/PO nanocomposites) have caught more attention from the application of automotive components, aerospace, furniture, building, home appliances, and sport. In this review, the surface modifications of nanocellulose and polyolefin are summarized respectively, such as surface adsorption modification, small molecule modification, and graft copolymerization modification. The common preparations of NC/PO nanocomposites are discussed, including the melting compounding, the solvent casting, and the in-situ polymerization. The lightweight, mechanical properties, and aging-resistant properties of NC/PO nanocomposites are highlighted. Finally, the potentials and challenges for industrial production development of NC/PO nanocomposites are discussed.

Structure and properties of particles/rubber composites applied on functionally graded lapping and polishing plate

To obtain uniform and controllable material removal on hard and brittle materials, a novel processing technology with functionally graded lapping and polishing plate (FG-LPP) was proposed. Taking application of particles/rubber composites and adjustable contact stress of workpiece as key point, the abrasive particles and rubber were mixed with different mass ratios; then the FG-LPP was formed with characteristics of required quasi-continuous distribution of Young’s modulus in the radial direction by two-step processing technique. The properties of Young’s modulus, loss factor, and glass transition temperature of different particles/rubber composites were tested and calculated. Through comparison and analysis, silicon carbide (SiC)/chloroprene rubber (CR) composites are the suitable application object of FG-LPP. Moreover, by laser particle size analyzer, scanning electron microscope, and X-ray diffraction, the size distribution of abrasive particles, micromorphology of particles/rubber composites and their phase composition were tested respectively to better reveal the structure and properties. The test results indicate that under the action of ZnO and MgO, CR undergoes a vulcanization reaction gently and forms a spatial three-dimensional structure. Thus, it helps to increase the intermolecular distance and weaken the intermolecular forces because the NO is easy to enter the CR molecules, which improves the intermiscibility between SiC and CR.