Dissertation > Excellent graduate degree dissertation topics show

Research on Manufacturing of MDF from Rice and Wheat Straws with Modified UF Resin and Pretreated Straw

Author: LianHaiLan
Tutor: YouJiXue;ZhouDingGuo
School: Nanjing Forestry University
Course: Forest Chemical Process Engineering
Keywords: Urea-formaldehyde resin Melamine Medium Density Fiberboard Enzyme Rice straw Wheat straw
CLC: TS653.6
Type: PhD thesis
Year: 2006
Downloads: 660
Quote: 7
Read: Download Dissertation


Due to the particularities of raw materials and the surface substances which inhibit water-based resin bonding, medium density fiber boards (MDFs) from rice straw and wheat straw bonded with conventional urea-formaldehyde resin (UF) do not have satisfactory properties as required, and commercial production line of those kinds of MDFs has not been built yet in China., In order to provide some theoretical foundation for manufacturing MDFs from rice and wheat straw, this research work dealt with the manufacturing optimization, performance modification and structure of the environment-friendly UF resin, investigated the influences of straw pretreatment both with chemicals and biology enzymes on the properties of the straw fiber boards bonded with UF resin, analyzed the differences existed among different layers of straw stalk and discussed the mechanism of manufacturing straw MDFs by different pretreating as well. The following conclusions were drawn based on the research:1. Urea-formaldehyde resin modified with Melamine ( MUF ) was a proper resin to bond rice and wheat straw fiber boards, and was an alternative to MDI resin in this application. The best 1 synthesis parameters of this resin were as follows: Moore ratio of formaldehyde to urea was.3, the pH value of the synthesis was 4.9-5.0, the reaction temperature was 85(?), and the addition amount of the melamine was 5%.2. By analyzing of mechanism of UF and MUF resins which prepared at the same molar ratio, it was found that the degree of glue joining improved with lower contents of methylol end groups and higher resistance to water attack. And DSC showed that MUF resin demanded higher curing temperature compared to UF resin. The surface tension of the MUF resin was 6.3% less than that of UF resin, hence the wetting ability of MUF to straw fiber was improved, which was good for MUF glue to diffuse and penetrate into fiber element and resulted in higher bond strength.3. Though all the straw pretreatments improved performances of straw-based fiberboards, straw pretreated with xylan enzyme was the best in terms of properties of the final boards. The best condition for this pretreatment were reached at a pH value was 4.5, a temperature of 45℃, a mass ratio of 6 to 1( water to straw), a time period of 2h and an enzyme dosage of 20IU·g-1. It was observed that the surface of wheat-straw became rougher and there were lots of pinholes in the cell wall by scanning the enzyme-pretreated straw with electricity microscope (SEM). Furthermore analysis of the fibers showed that among all fibers defibrated from straws pretreated with different methods, fibers refined from xylan enzyme pretreated straw had the longest average fiber length, the largest length-to-width ratio, the highest proportion

Related Dissertations

  1. Studies on Fermentation Optimization, Purification and Enzyme Characteristics of Lipase from Aspergillus Oryzae FS-1,TQ925.6
  2. Directed Evolution of Lipase from Penicillium Expansum FS1884 by Error Prone PCR,Q78
  3. Effects of Enzyme/Chemical Agents on Refining of Plant Fiber,TS713
  4. Study on the Preparation of the Low Molecular Weight Fuciodan from Sargassum Henslowianum (C.Agardh) and Anti-tumor Activity,TS254.9
  5. Establishment of ELISA for Detecting Cd-MT of Pteria Penguin and Preliminary Study of ELISA-kit,X835
  6. Melamine Residue and Disappearance in Tilapia,S963
  7. The Environmental-Friendly Method and Process of Removing Non-Cellulosic Matters from Bamboo for Textile Fiber,TS652
  8. Effects of Different Reconciled Corn Oils on Antioxidative Stress, Lipid Metabolism Enzymes, and Abundance of Immune-related Genes of Broilers,S831.5
  9. Stereoselective Metabolism of Tetrahydropalmatine and Its Effect on Hepatic Drug Metabolism Enzymes,R96
  10. Research on Melamineanalysis Method in Milk Powder and Establish the System of Rapid Determination,O657.3
  11. Fire Retardancy Performance of Poly (Ethylene Terephthalate) Containing Melamine Cyanurate,TB383.1
  12. Research on Anaerobic Fermentation Processing Technology of Dead Tilapia,TS254.4
  13. Assessment of Resistance Risk in Spodoptera Exigua (Hubner) and Spodoptera Litura (Lepidoptera: Noctuidae) to Chlorantraniliprole,S433
  14. Theeffect of Environmental Factor on Rooting Culture of Paeonia Suffruticosa in Vitro,S685.11
  15. Comparative Analysis of Growth, Digestive Enzyme Activities and Pearl-SAC Development Between Two Different Sized Pinctada Martensii during Pearl Culturing,S917.4
  16. The Difference of Proteome Expression of Low Light Stress and Regular Light Recovery on Growth of Maize Seedling,S513
  17. Study on the Mechanism of Night Temperature to Grain Filling of Inferior in Rice,S511
  18. Coparative Analyses of Carbon and Nitrogen Metabolism of Flue-cured Tobacco Growing in Henan and Yunnan,S572
  19. Effects of Organic, Specially Grown and Conventiinal Farming Systems on Vegetable Yield, Quality and Soil Fertility in Nanjing Region,S63
  20. The Effectr of Lactic Acid Bacteria and Rice Bran on Dynamic Change of Rice Straw Silage Fermentation,S816.53
  21. Study of a Thermophilic Bacteria Chitin-binding Domain and Its Application in Immobilized Enzyme,Q814

CLC: > Industrial Technology > Light industry,handicrafts > Wood processing industry,furniture manufacturing industry > Processing > Wood-based panel production > Fiberboard
© 2012 www.DissertationTopic.Net  Mobile