Preparation And Study On The Properties Of Nano-Eco-composites Reinforced By Bacterial Cellulose

By using bacterial cellulose as reinforcement, natural macromolecular starch and synthesized UPR (unsaturated polyester resin) as matrix, eco-composites were prepared by the method of aldehyde-initiated crosslinking reaction and RTM (resin transfer moulding) method. Systematical researches were carried out on the properties of mechanical, moisture absorption, degradation and effect of fibre surface treatment on these properties of composites.The results show that crosslinked network was formed in the microstructure of ST/BC composite. Chemical bonding was formed at the interface of UPR/BC composite by surface treatment of BC, which enhanced the mechanical properties of composites. Tensile strength, flexure strength, shear strength and Young's modulus were increased by 117.7%, 38.4%, 38.7% and 27.6% respectively. As fibre volume fraction increased, ST/BC composites got an increase in tensile strength as well as a decrease in elongation at break. The best tensile strength of 152.9 MPa could be obtained in UPR/BC composites with the fibre volume fraction of 20%.Under the condition of 75% RH, moisture absorption processes of ST/BC composites didn't fit Fick's law, absorption rate and equilibrium content of water were lower than the starch matrix, and continue to drop as the fibre volume fraction increase. The processes of moisture absorption of UPR/BC composites were described by Fick's Law. Coupling treatment of BC fibres lowered the absorption rate and equilibrium water content, but which will rise while BC volume fraction increases.Soil burial test and enzyme degradation test were carried out to testify the degradability of ST/BC composites. The results showed that mass loss of both starch matrix and composites reached 30% after buried for 30d, and the degradation rate of ST/BC composite was approximately 25% after enzyme degraded for 36h. UV radiation test was carried out on UPR/BC composites. XPS results proved that an oxidative degradation took place when the energy of ultraviolet was absorbed by the composites, contents of oxygenic functional groups increased after exposed to ultraviolet radiation. Photodegradation occurred to a certain extent.