Preparation And Properties Of Styrene Butadiene Rubber/Chitin Nanocrystal(CNCs) Nanocomposites

The use of bio-renewable resources to replace fossil resources not only solves the problem of raw materials, but also realizes the sustainable development and reduces the pollution. There are many potential applications in polymer nanocomposites for nano-sized chitin.Chitin whiskers(CNCs)prepared by acid hydrolysis show rod-like morphology with diameter of ~15 nm, length of 200~500 nm and aspect ratio of 13~33. The strong ultrasonic treatment made CNCs be peeled into a stable nano-dispersion state completely in the aqueous phase. Unvulcanized and vulcanized carboxylated styrene-butadiene rubber(x SBR) composites with CNCs were prepared by solution-casting method. There are hydrogen bonding interactions between the rubber and CNCs. CNCs can significantly increase the tensile strength, tensile modulus, and strain at break of x SBR. CNCs are uniformly dispersed in the rubber matrix. The storage modulus of the composites at rubber region increases by CNCs. The glass transition temperature of x SBR nearly does not change after the incorporation of CNCs. x SBR/CNCs nanocomposites also have the water response of mechanical properties. Upon submersion in deionized water, dramatic reduction of tensile modulus is observed for the nanocomposites. The mechanical properties of the composites are returned to the original level after drying again. These phenomenons are interpreted as the formation of percolating CNCs network by hydrogen bonding in the composites. x SBR/CNCs nanocomposites have the properties of shape memory. The addition of CNCs improves the water absorption and wettability of x SBR, and the bound rubber is formed in the composite materials.Styrene butadiene rubber(SBR) vulcanized compounds with chitin nanocrystals(CNCs) were prepared by mechanical kneading method. The addition of CNCs increases the elastic torque of SBR and reduces the value of TC90. CNCs can significantly increase the tensile modulus of SBR, but the strain at break of SBR decreases. The wettability of vulcanized compounds also increases and the relative weight loss after swelling in toluene decreases by the incorporation of hydrophilic CNCs.In summary, CNCs from renewable resources can be used as a new type of nanoparticles to reinforce rubber, and these advantages make x SBR/CNCs nanocomposites have a application in the field of high-performance elastomeric materials and intelligent materials.