A High Strength Nanocomposite Based on Microcrystalline Cellulose and Polyurethane

Abstract

A high-strength elastomeric nanocomposite has successfully been prepared by dispersing microcrystalline cellulose in a polyurethane matrix. The resulting nanocomposites show increased strain-to-failure in addition to increased stiffness and strength compared to the unfilled polyurethane. The optimal composite contained 5 wt % cellulose. The average true strength for this composition was 257 MPa, compared with 39 MPa for the neat polyurethane, and showed the highest strain-to-failure. The improvements of stiffness, strength, as well as strain-to-failure are believed to be due to good interaction, by both covalent and hydrogen bonds, between the polyurethane and the cellulose nanofibrils.

High‐strength composites based on tung oil polyurethane and wood flour: Effect of the filler concentration on the mechanical properties

“…Besides, higher strength can also be observed in systems with good interfacial interactions, while deformation at break decreases significantly [8,[20][21][22]. In general, the reason for the failure of microcomposites at low strains is the initiation of the failure by interfacial debonding at multiple sites, which is followed by the coalescence of the cracks and final catastrophic crack growth [9,23,24]. In our system, the mentioned failure mechanism is not present because of the excellent interfacial adhesion, which largely delays the final breakage of the material.…”

“…In our system, the mentioned failure mechanism is not present because of the excellent interfacial adhesion, which largely delays the final breakage of the material. Besides, the WF added to the composites and coreacted with the polyurethane can act as a chain extender, much in the same way as short diols added to segmented polyurethane formulations [9]. However, as more WF is added, the increased crosslinking and rigidity of the particles produce the overall traditional effect of increasing the composite modulus and reducing deformability of the material.…”

“…In general, the incorporation of fillers to polyurethanes results in higher modulus due to the stiffness of the particles and also higher strength when the interface fiber-matrix is good, but the ultimate strain is reduced. Recently, a work on nanoparticles reinforcing rubbery polyurethanes has reported an increase in modulus and strength without sacrificing the high deformation at break of the polymer matrix [8,9].…”

Cellulose Whisker/Epoxy Resin Nanocomposites

“…The formidable mechanical enhancement observed in these materials was explained by the formation of a percolating whisker network in the polymer matrix, in which stress transfer among the whiskers is facilitated by hydrogen-bonding. Since then, an extensive list of nanocomposites comprising cellulose whiskers has been explored, involving different kinds of cellulose whiskers as well as a broad range of polymeric matrixes, including poly(ethylene oxide) (13,14), poly(vinyl chloride) (15), poly( -hydroxyoctanoate) (16), starch (17), polypropylene (18), poly(caprolactone) (19), ethylene oxide/epichlorohydrin copolymers (20)(21)(22)(23)(24), polystyrene (21), polybutadiene (21), poly(vinyl alcohol) (25), poly(butyl methacrylate) (26), and polyurethanes (27,28).…”

Structure and Mechanical Properties of Thermoplastic Composites Using Microcrystalline Cellulose Nanofibers

“…특히 최근의 극세화와 경량화 제품개발 경향에 따라 나노소재에 대한 관심이 매우 높아졌고, 섬유복합재 료의 보강재로 MCC나 MFC를 통해 나노크기를 갖도록 제 조된 셀룰로스 나노섬유(cellulose nanofiber, CNF)가 적용 되고 있다 [12]. 폴리우레탄(polyurethane, PU)과 MCC의 복 합재료에 대한 선행연구 [13] …”