Preparation And Properties Of Alkali And Xylanase Cooperating With Hydroxyapatite Modified Bamboo Powder/Polylactic Acid Composites

Improving the interfacial compatibility of natural bamboo fibers and thermoplastic polymers is the key to the preparation of bamboo fiber reinforced thermoplastic polymer composites;in the current research,collaborative modification has gradually become a research trend,including biological modification,inorganic nanoparticles modification can be used as a major development direction for future research on bamboo fiber reinforced resin matrix composites.In this thesis,nano-particle nano-hydroxyapatite?N-HA?and hemicellulose hydrolase-xylanase are used as modification materials,the modified bamboo powder and polylactic acid?PLA?were hot-pressed by four modified methods of alkali,alkali/N-HA,xylanase,xylanase/N-HA bamboo powder and the composites was taken as the research object,and the modified composites was tested.Based on the chemical modification and biological enzyme modification of inorganic particles on the surface treatment of bamboo powder,the development of a new method of enhancing the bamboo-plastic interface after compounding with plastic,the conclusion after analysis is as follows:?1?After alkali treatment with different concentrations,when the alkali concentration is 5 wt%,the mechanical properties of the composites are the best;the crystallinity is increased to 43.74%.The Fourier transform infrared spectroscopy?FTIR?,water absorption,scanning electron microscope?SEM?,thermogravimetric?TG?analysis also show that proper alkali concentration modification can improve the compounding of bamboo powder and PLA.?2?After the alkali/N-HA synergistic modification treatment,the synergistic effect is better than the single alkali treatment,and when the content of N-HA is in the range of less than 15 wt%,the performance of mechanics,crystallinity,water absorption,and TG analysis are improved,taking the mechanical performance results as the main reference,the synergy ratio is 5 wt%alkali and 5 wt%N-HA.?3?After treatment with different concentrations of xylanase,when the concentration of xylanase is 2.67mg.L^-1,the composites has the best comprehensive mechanical performance;the comprehensive performance shows that the modification effect of xylanase is more gentle than alkali treatment,and the improvement effect is weaker than that of alkali treatment.?4?After the synergistic modification treatment of xylanase/N-HA,the synergistic effect is better than that of single xylanase.When the content of N-HA is10 wt%,the composites has comprehensive performance and the synergistic treatment condition is 2.67 mg.L^-1xylanase and 10 wt%N-HA;the effect of the amount of N-HA added on the composites after xylanase/N-HA treatment is weaker than that of alkali/N-HA modification.