Dynamic mechanical properties of sisal fiber cellulose microcrystalline/unsaturated polyester in-situ composites

Sisal is a natural material and a potential additive to reinforce composites. In this paper, sisal fiber cellulose microcrystalline (SFCM) was obtained from sisal fiber, and SFCM/unsaturated polyester (SFCM/UPR) in-situ resins were prepared via in-situ polymerization. Moreover, SFCM/UPR composites were produced with methods of rolling and molding. Effect of SFCM on dynamic mechanical properties of composites was studied. It is demonstrated that SFCM could significantly improve the dynamic mechanical properties of composites; the effect is closely related with the amount of SFCM, its dispersion in UPR matrix, and interfacial interaction. When the content of SFCM was 3wt%, at 50 degrees C, the storage modulus of SFCM/UPR composite was 33.22% higher than that of pure UPR. In addition, the glass transition temperature (T-g) was shifted to a higher temperature by 7.5 degrees C, and loss modulus was decreased by 16.24%. The equilibrium value of relaxation modulus at 120min was 30.52% higher than that of pure UPR composite. Besides, the equilibrium value of creep strain at 120min was decreased by 41.61% compared with pure UPR composite. Copyright (c) 2015 John Wiley & Sons, Ltd.