Effect of different shell materials on the mechanical and thermal properties of core-shell structured bamboo-plastic composites

The purpose of the study was to inspect the mechanical and thermal properties of four kinds of core-shell structured bamboo-plastic composites (BPCs). The materials that were used for the fabrication of the BPCs were high density polyethylene (HDPE), bamboo pulp fibers (BPF)/HDPE, nano-CaCO3/HDPE, and white mud (WM)/HDPE. As verified by flexural properties and impact properties, the dispersion of the BPF, nano-CaCO3, and WM in the HDPE matrix was inhomogeneous. The fracture surface of the scanning electron microscope (SEM) images showed that some aggregates existed in the HDPE. Additionally, X-ray diffraction (XRD) was used to corroborate the results. The thermogravimetric analysis (TGA) showed that the samples with the WM/HDPE shell has little effect on the thermal stability. However, the apparent activation energy (Ea) values of the nano-CaCO3/HDPE shell were higher than those of the other samples, which indicated better thermal stability. The thermal stability had no remarkable changes with the addition of the WM and BPF. The differential scanning calorimeter (DSC) curves revealed that the relative crystallinity of the BPCs increased with the addition fillers, which suggested that the fillers can act as nucleating agents.

Effects of two-organic-acid-dissolved chitosan on antibacterial properties of bamboo pulp-based fabrics

Bamboo pulping fabrics (BPFs), one of the most important textile materials for clothing industry, has many excellent characteristics such as soft, skin-friendly, and hygroscopic, etc., but some drawbacks especially mildewed, causing customers’ concerns. This experiment evaluated effects of two organic acids, acetic acid (AA) and citric acid (CA), as solvents for dissolving chitosan on the antibacterial properties of chitosan-treated BPFs with the intention of replacing AA with CA because previous research finding indicated the strong acid smelling of BPFs treated with chitosan dissolved in AA. Experimental results indicated that BPFs treated chitosan dissolved in CA had a significantly higher antibacterial rate than ones treated with chitosan dissolved in AA within each of five chitosan mass fraction levels investigated. Antibacterial rates of BPFs treated with chitosan dissolved in AA and CA increased as chitosan mass fraction increased, but increasing rates were different between BPFs treated with chitosan dissolved in AA and CA. No acid sour smell was detected for BPFs treated with chitosan dissolved in CA.

Effect of nanofibrillated cellulose made from enzyme-pretreated bamboo pulp on paper strength

The applicability of bleached bamboo kraft pulp (Ba-BKP) was explored as a raw material for the manufacture of nanofibrillated cellulose (EN-NFC) made of enzyme-pretreated pulps and the effects of the EN-NFC on enhancing paper strength. The Ba-BKP was pretreated using an endo-glucanase enzyme at 50 °C and pH 6, after which the EN-NFC was made by micro-grinding. Bleached hardwood kraft pulp (Hw-BKP) was used as a control, and the non-enzymatic refining pretreatment of BKPs was compared with the enzyme pretreatment. The EN-NFC was incorporated into handsheets, and the sheet strengths were measured. The physical properties of the NFC made from the Ba-BKP were similar to those made from the Hw-BKP. The NFC prepared following enzyme pretreatment were smaller and more uniform than those pretreated with refining. The EN-NFC made from the Ba-BKP was effective at enhancing tensile index by 52.7%, and burst index by 210.2% when 2% of EN-NFC was added in the furnish, and those of handsheets containing the EN-NFC made from Hw-BKP showed the similar improvement. Therefore, Ba-BKP can be used as a raw material for the manufacture of EN-NFC that confers similar physical properties and strength enhancement to paper as those made from Hw-BKP.

Study on the Effects of Technology Parameters on the Bending Strength of Press Bamboo Powder Plywood

The application of bamboo by-products such as bamboo branches, debris... to recycle and produce bamboo powder plywood, perfectly saves high price natural resource of national wood with artificial wooden boards made from bamboo powder that ensures the reservation of natural source of raw materials and protecting of environment. Plywood that is made from bamboo powder has both economic and environmental benefits. It is an urgent task for providing a new version of material for civil engineering in Vietnam. The paper presents a study of the effect of technological parameters on the bending strength of pressed bamboo pulp plywood in order to enhance the mechanical properties of a new domestic product of construction in Vietnam.