دانلود رایگان مقاله آمیزه قالب گیری ورقه (SMC) مواد مرکب حاوی نانوبلور سلولز

Abstract

A scalable technique was introduced to produce high volume lightweight composites using sheet molding compound (SMC) manufacturing method by replacing 10 wt% glass fibers (GF) with a small amount of cellulose nanocrystals (CNC). The incorporation of 1 and 1.5 wt% CNC by dispersing in the epoxy matrix of short GF/epoxy SMC composites with 25 wt% GF content (25GF/CNC-epoxy) produced 7.5% lighter composites with the same tensile and flexural properties of 35GF/epoxy composites with no CNC. The addition of 1 wt% CNC in 25GF/CNC-epoxy SMC composites resulted in increases of 15% in elastic modulus, 11% in flexural modulus and 14% in flexural strength, reaching the corresponding properties of 35GF/epoxy SMC composites. Moreover, it was found that although addition of CNC did not alter the impact energy, removing 10 wt% GF resulted in reduction of impact energy.

5. Conclusions

The idea of high volume production of light weigh composites with no compromise in mechanical properties was verified by replacing part of the GF with CNC in GF/epoxy composites made using SMC manufacturing method. It was demonstrated that introducing small amount of CNC, i.e. 1 and 1.5 wt%, in epoxy resin used in the SMC manufacturing process allowed removing 10 wt% GF from SMC composites reducing the composite weight by 7.5% without any reduction in tensile and flexural properties. Enhancement in storage and rubbery moduli were also recorded for both CNC/epoxy and GF/CNC-epoxy SMC composites, demonstrating the stiffening effect of CNC. In addition, Tg of 25GF/CNC-epoxy SMC composites with 1.5 wt% CNC slightly increased compared to that of the corresponding composite with no CNC. Specifically, incorporation of 1 and 1.5 wt% CNC in 25GF/CNC-epoxy SMC composites increased the tensile and flexural modulus by 15% and 11% respectively and flexural strength by 14% with respect to the properties of the corresponding SMC composites with no CNC. Significantly, the enhanced properties of 25GF/CNC-epoxy SMC composites increased to the level of 35GF/epoxy SMC composites with no CNC, indicating that a 7.5% lighter (lower density) composite achieved the required mechanical properties of a composite with 10 wt% more GF. Further, it was found that introducing CNC does not alter the impact energy; however, taking out GF reduced the impact energy. The results of this study indicate that producing high volume lightweight SMC composites that meet industrial standards is feasible through using cellulose nanomaterials.