Fabrication of Crack-Free Flattened Bamboo and Its Macro-/MicroMorphological and Mechanical Properties

This work aimed to help the bamboo industry develop methodology for producing imperfection-free bamboo boards that can serve either decorative or structural benefit to consumers seeking to engage with the bioeconomy.Specifically,softened and slotted bamboo tubes were handled by a roller device with nails to render crack-free flattened bamboo board.Softening temperature and time were optimized herein according to findings regarding chemical composition and board mechanical properties.The optimal softening parameters for saturated steam heat treatment is proved to be 160°C for 8 min.The flattened bamboo board possesses an increased bending strength of 101.5 MPa and a decreased bending modulus of 7.7 GPa,being compared with only-softened bamboo.The corresponding changing mechanism is determined in-depth by the micro-morphological and mechanical results based on in-situ SEM and AFM technologies.Under the action of nails and rolling processes,the bamboo texture becomes compact with crushed and fragmented conduit walls.The resulting cell cavity then becomes stretched and compressed,taking on a morphology which allows for the mechanical penalties associated with flattening to be avoided.According to the micro-mechanical results obtained by AFM,compared with unflatten bamboo,the Young’s modulus of the cell membrane in transverse direction(YT)decreases to 1.00 GPa while the corresponding Young’s modulus in radial direction(YR)increases to 7.29 GPa.

Study on Preparation of Lignin-Containing Nanocellulose from Bamboo Parenchyma

Bamboo vascular bundle fiber and parenchyma(BP)are separated by high-temperature treatment with saturated steam.Bamboo vascular bundle fiber is widely used in the market,but how to develop and utilize parenchyma tissue is a difficult problem.The sulfated cellulose nanofibers(ANFs)were obtained by sulfating BP with a deep eutectic solvent(DES),which provided a theoretical basis for the value-added utilization of BP.Using DES as the reaction medium and reagent,the BP was grafted with a sulfonic acid group to form a gel substance in water,ANFs and nanocellulose gel were obtained by ultrasonic cell crusher.The highest yield of ANFS was 75%.The width of the ANFs was about 3 nm,and a small number of nanofiber aggregates existed at the same time.A high aspect ratio of ANFs,due to their high viscosity,has potential applications as enhancers at low concen-trations.Lewis acid(ZnCl 2)added based on binary(DES)greatly improved the thermal stability of the ANFs and maintained the crystal form of cellulose I.