Papers by Author: Hai Peng Yu

Abstract: To convert the hydrophilic cotton fiber into hydrophobic, grafting methyl methacrylate (MMA) on cotton fiber surface using ARGET (activators regenerated by electron transfer) ATRP (atom transfer radical polymerization) was studied in this paper. Four parallel experiments with different reaction time (2h/4h/6h/8h) were designed. The modified cotton fibers and the untreated control were examined using FTIR, SEM and contact angle analysis. The results show that as the reaction time prolonged, the peak of carbonyl stretching band of 2-bromoester at 1730cm-1 was stronger and the surface of cotton fiber was rougher, which demonstrates MMA has been grafted on the surface of cotton fiber successively and its amount increases with the reaction time. As the results of contact angle measurement, it shows that the hydrophilicity of cotton fiber can easily be modified by grafting of MMA, but the increasing amount of grafting chain had no obvious effects on further improving its hydrophobicity.

Abstract: Cellulose micro/nano fibrils generated from biomass are relative new reinforcing materials for polymer composites, which have potential lightweight and high strength and are renewable. In the present study, the preparation method of extracting cellulose micro/nano fibrils from wood was introduced. After successful disintegration, the morphological characteristics of the wood fibers, purified cellulose fibers, cellulose fibers activated by ultrasonic-wave and cellulose micro/nano fibrils after homogenization treatment, were compared by visual examination and scanning electron microscopy. The results showed that cellulose micro/nano fibrils have been efficiently extracted from wood, which have great potential in the application areas of papermaking, bio-nanocomposites, food, cosmetics/skin cream, medical/pharmaceutical, and so on.

Abstract: Controlled anatase TiO2 was grown on cellulose surface using a fragile hydrothermal method in different conditions. With the analysis of FTIR spectra, the grown TiO2 was chemically attached to the cellulose surface. The morphologies and amount of grown TiO2 on cellulose surface could be controlled through the adjustment of reacting factors. From the observation of SEM images, the morphology and content of TiO2 grown on cellulose surface could be controlled under appropriate reaction conditions. Under the regulation of reactant conditions, the content ranging from 8.7%-34.2% of TiO2 could be grown on cellulose surface.

Abstract: Regenerated cellulose/polyvinyl alcohol (PVA) blend membranes were prepared from a solution of cellulose and PVA in an ionic liquid of 1-allyl-3-methyimidazolium chloride (AMImCl). SEM images showed that the phase separation on the mixture was severely formed when the content of PVA was higher than 10% by volume. However, when the content of PVA in the mixture was lower than 6%, the cellulose and PVA were well-distributed. The regenerated blend membranes using the AMImCl presenting reasonable crystallinity were superior to those of regenerated pure cellulose membrane. In conclusion, the compatible properties of blend membranes from regenerated cellulose/PVA (6%) were improved and the blend membranes kept original biodegradability.

Abstract: As the WAP (Wooden Acoustic Panel) is a kind of newly-emerged functional and decorative building material, this dissertation conducted a scientific analysis on its qualitative and functional design requirements. The method of QFD (Quality Function Deployment) was introduced in this dissertation. Through market survey, voice of customer about qualitative requirements on the WAP was obtained, while a customer needs deployment table was gained based on requirement transformation and clustering. Then a technical requirement deployment table was prepared corresponding to the customers’ requirements. Finally, the quality house for product plan and location of components were acquired. The result indicates that the quality and function requirement of WAP obviously cover the following perspectives: firstly attaching great importance to improvement in acoustic absorption and price reduction, specifically paying attention to material selection of core materials, panel thickness, punching rate and aperture; secondly taking environmental protection and decorative function into consideration which means to concern surface material selection, decorative function and glue joint technique, and finally thinking about the sizes of panels and convenience in installation.

Abstract: Standing wave tube was used to test the sound absorption abilities and analyze the influence factors of perforated medium density fiberboard (MDF). The test results show that bore diameter, perforated rate and different depth of space from the structure are the key factors influencing the absorption performance of wooden perforated panels, but decorative facing and bore shape have a little contribution to absorption abilities. Research finds that absorption peak will move towards high-frequency with decreasing the bore diameter so as to increase absorption effect in high-frequency, and excellent high-frequency absorption performance can be achieved by increasing perforated rate. On the other hand, larger depth of space from the structure will raise the absorption abilities in low-frequency of the panel.

Abstract: Based on the fast-growing and abundant lightwood as ground mass, the study applies the formation principle of aerogel, uses such low-carbon treatment technologies as sol-gel method, Lowry method and supercritical drying method, prepares and forms an environment-friendly aerogel-type wood. The result of study shows that the new type of material not only has the natural biological structure of wood, but also has some fine features of aerogel, and is easily accepted by the environment.

Abstract: In this paper, we focus on a new wood-based panel unit, which was named Micron Wood Flake for its large size in length, a very small size in thickness, and especially its wooden color in appearance. The flakes were obtained by mechanical processing on waste wood based on the micro-processing theory and technique. In order to design the device and determine the key processing parameters, a simulation of micron wood flake was proceeded based on a mathematical model of single wood cell proposed here. Comparing with the experiments results, it showed that the model is feasibility to some extent. In contrast to the other methods of disposing waste woods, the method proposed here is no environment pollution absolutely, consequently, as an application of this kind flakes, a new environment-friendly decorative board was developed, and the physical and mechanical properties of the samples reaches Japanese light particleboard standard JISA5908.

Abstract: According to the three-factor theory, the surface roughness of different wood-based environmental materials was evaluated using the surface roughness profiling instrument, and the underlying effective factors of the differences were analyzed. The psycho-physiological examination of the materials’ roughness on human psychology and physiology was also carried out. During the examination, physical roughness factors of the materials were treated as the independent variable, and the heart rate variability (HRV) and dynamic blood pressure (DBP) were chosen as the dependent variables. The sympathetic and parasympathetic activities of human autonomic nervous system as toughing material surface were investigated depending on the time domain analysis of HRV. The results showed that there exists a negative linear correlation between the physical roughness of materials and the human psycho-physiologic indexes. Overall, wood materials were proper to physiological stimulate of the body, they can’t cause the risk of physiological imbalance and would soon return to normal mentation after touching. Mental capacity with HRV of the body could illustrate the suitable tactile sense characteristics with the performance of the basic physical quantities of wood materials.

Abstract: Microfibrillated cellulose (short for MFC) has rapidly advanced due to its unique nano-order-unit web-like network structure and such special properties as extremely high strength, large specific surface area and high aspect ratio. In the present paper, the processing technology and the research progress of the preparation methods of MFC with mechanical and it combined with enzymatic treatment are briefly reviewed, then the four main challenges about preparation of MFC are figured out. In the last section, the direction of this research field is also highlighted.