Self‐crosslinkable lignin/epoxidized natural rubber composites

Abstract

Self-crosslinkable lignin/epoxidized natural rubber composites (SLEs) were prepared through a high-temperature dynamic heat treatment procedure followed by a postcuring process. Because of the ring-opening reaction between lignin and epoxidized natural rubber (ENR), lignin as a crosslinker and reinforcing filler was uniformly dispersed into the ENR matrix and was highly compatible with the polymer matrix; this was confirmed by scanning electron microscopy. The curing behavior, mechanical properties, and dynamic mechanical properties of the SLEs were studied. The results show that the crosslinking degree, glass-transition temperature, modulus, and tensile properties of the SLEs substantially increased with the addition of lignin. A physical model was used to verify the strong interactions between lignin and ENR. Stress-strain curves and X-ray diffraction suggested that the reinforcement effect on the SLEs mainly originated from lignin itself rather than from strain-induced crystallization.

Reinforcing styrene butadiene rubber with lignin-novolac epoxy resin networks

“…The M H of N-SBR/50lignin/F51 compounds increases significantly with the increasing loading of F51. As an increase in torque is proportional to the crosslinking density [18]. It is evident that the crosslinked networks are formed due to the crosslinking reactions between lignin and F51.…”

“…Numerous scientific articles relating to preparations of lignin as curing agent in epoxy resin have been published [16,17]. Self-crosslinkable lignin/epoxidized natural rubber composites were prepared by the ring-opening reaction between lignin and epoxidized natural rubber in our research group [18]. Epoxy resins also have been synthesized by an insitu vulcanization to reinforce SBR [19].…”

A New Class of Renewable Thermoplastics with Extraordinary Performance from Nanostructured Lignin‐Elastomers

“…At higher magnifi cation, lignin particles are visualized as interconnected lamellae of less than 100 nm thickness in NBR-41 matrix (Figure 3 c), and as tiny protruding particles less than 50 nm in diameter in NBR-51 (Figure 3 e). [ 14 ] In that case, the lignin improved the tensile property of ENR matrix and achieved moderate tensile strength (12 MPa). The SAXS pattern of NBR-33 blend exhibited asymptotic decay in scattered intensity, implying that phase-separated domains larger than the measurable size range (1-160 nm) of our SAXS occurred in the blend.…”

“…Previous reports [11][12][13][14] on incorporation of lignin into rubbers as a potential candidate for the replacement of the conventional reinforcement, carbon black, showed little effect on rubber reinforcing due to its large particle size and lack of interfacial interactions. Our method involves fractionating a rigid, thermally malleable lignin that then can be melt-mixed with appropriate soft commodity rubbers to form high-performance polymers with precisely controlled morphology.…”

The Effect of Epoxidation on Strain‐Induced Crystallization of Epoxidized Natural Rubber

“…Since then, Hashim and Kohjiya reported the SIC behavior of ENR crosslinked with sulfur, peroxides, amines through mechanical experiments, and Mooney–Rivlin plots. Jiang et al performed X‐ray experiments on the lignin‐crosslinked ENR, but did not observe SIC. Imbernon et al used X‐ray measurements to reveal the SIC behavior of ENR‐25 crosslinked with dodecanedioic acid and describe the orientation of amorphous phase during cyclic stretching.…”