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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 3 wt%, at 50°C, the storage modulus of SFCM/UPR composite was 33.22% higher than that of pure UPR. In addition, the glass transition temperature (Tg) was shifted to a higher temperature by 7.5°C, and loss modulus was decreased by 16.24%. The equilibrium value of relaxation modulus at 120 min was 30.52% higher than that of pure UPR composite. Besides, the equilibrium value of creep strain at 120 min was decreased by 41.61% compared with pure UPR composite. Copyright © 2015 John Wiley & Sons, Ltd.

In this paper, the effects of preparation methods on mechanical and tribological properties of sisal fiber cellulose microcrystalline (SFCM)/unsaturated polyester (UP) composites were studied. Compared with the pure UP composites, the SFCM/UP composites prepared by in-situ polymerization had greatly improved the mechanical and tribological properties. The impact strength, flexural strength, and flexural modulus of SFCM/UP composites with 2 wt% SFCM were 6.8 KJ/M2, 105.53 MPa, and 14.29 GPa, increased by 74.81%, 33.38%, and 7.36% in comparison with pure UP composites, respectively. Meanwhile, the volume wear rate of SFCM/UP composites at 100, 150, and 200°C decreased 50.40%, 52.39%, and 50.06%, respectively. These results suggested that the properties of SFCM/UP composites prepared by in-situ polymerization were significantly improved, which may be attributed to the strong interface interactions between SFCM and UP matrix. Copyright © 2015 John Wiley & Sons, Ltd.

In this paper, sisal fiber cellulose microcrystal (SFCM) was prepared by the sulfate pulping method, and sisal fiber cellulose microcrystal/unsaturated polyester (SFCM/UP) in situ resin was polymerized. Furthermore, the SFCM/UP composite was prepared by rolling and molding techniques. Effects of SFCM content on mechanical and wear properties of the UP composites were studied. Structure and properties of the in situ SFCM/UP resin and its composites were characterized by using Fourier transform infrared, polarized optical microscopy, thermogravimetric analysis, scanning electron microscopy, and other methods. The results showed that the addition of SFCM by in situ polymerization significantly improves the thermal stability of UP: The decomposition temperature (Td5) of SFCM/UP in situ resin, at thermal weight loss of 5%, is increased by 16°C compared to that of the pure UP resin. On a condition that the SFCM content was 2%, the impact strength, flexural strength, and flexural modulus of SFCM/UP composites are higher than those of UP composites by 41.08%, 52.52%, and 32.31%, respectively. Moreover, the addition of SFCM significantly enhances the wear properties of unsaturated polyester composite at 200°C; the volume wear rate of SFCM/UP composite is lower than that of UP composites by 64%, indicating SFCM could significantly strengthen and toughen UP composites.