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MINISTRY OF EDUCATION AND TRAINING MINISTRY OF AGRICULTURE AND RURAL DEVELOPMENT VIETNAMESE ACADEMY OF FOREST SCIENCES VU ĐINH THINH Study on some technological parameters to fabricate particle boards made from Acacia mangium Wild bark Specialty: Forest product processing technology Code : 9549001 SUMMARY OF TECHNICAL PROGRESSION THESIS Hanoi, 2020 The work was completed at the Vietnamese Academy of Forest Sciences Supervisor: Assoc Prof Dr Vu Huy Dai Assoc Prof Dr Nguyen Thi Bich Ngoc Chairman: Reviewer 1: Reviewer 2: Reviewer 3: The dissertation is defended in front of the Institute's thesis-judging council Vietnamese Academy of Forest Sciences At hours minute, day month year 20 The dissertation can be found at: National Library and Vietnamese Library Academy of Forest Sciences PUBLISHED SCIENTIFIC WORKS RELATED TO THE THESIS Ta Thi Phương Hoa, Vu Dinh Thinh, Vu Huy Dai, 2013 “Determining the main chemical and physical properties of Acacia mangium bark" Journal of Agricultural Science and Rural Development, 22: 117-120 Vu Dinh Thinh, Vu Huy Dai, 2016 “The influence of bark rate on the mechanical properties of A acacia bark composite boards ” Journal of Forestry Science, 4: 4749-4753 PREFACE Rationale and problem statement Currently, the recovery rate of plantation timber in Vietnam is very low, approximately 30% - 35% In a tree, the bark proportion is about 10 - 15%, branches: 25-30%, roots: 10-15% Bark, roots, leaves are all left in forest, and not being used for the production of fiberboard and particle board, and new types of products Study on the use of bark to produce composites is needed to improve the efficiency of using wood materials and open up a new trend of efficient use of bark in the wood processing industry Acacia species have outstanding advantages in growth rate and are suitable for many ecological regions in Vietnam Acacia forest area accounts for about 75% of the plantation forest area The volume of bark is relatively large Therefore, detailed study is required to investigate the effect of different parameters on the production of Acacia mangium bark-based composite Research objectives 2.1 Theoretical objectives: (1) Determine the effect of different parameters (time, temperature) on the quality of the composite without adhesives; (2) Determine the effect of bark and wood chips ratio on the quality of the composite with adhesive 2.2 Technical objectives: (1) Investigate parameters used for the production of the bark - based composite; (2) Determine the ratio of bark and wood chips; (3) Proposing suitable parameters for the production of the composite from A mangium bark that meet the standards of construction materials (soundproof and heatproof boards) Material: Acacia mangium bark of - 10 years old, selected from Hoa Binh Scope of research Fixed elements: The raw materials were the bark of Acacia mangium - 10 years old and scraps of Acacia mangium peeling process in Hoa Binh; Adhesives: UF glue (Urea-Formaldehyde), 10% glue Using molds with dimensions (length x width x thickness) of 400 x 400 x 16 mm; Expected a desity of composite board: γ = 0,750g / cm3; Pressing pressure (P): 1.6 MPa Change factors: Change the pressing parameters (time, pressing temperature) to make a bark composite with and without using adhesive: + levels of pressing time (τ): τmin = 16 minutes, τo = 18 minutes, τmax = 20 minutes + levels of temperature (T): Tmin = 160oC, To = 180oC, Tmax = 200oC Output factors: Main mechanical properties of bark composite boards: density, thickness swelling, water absorption, MOR and MOE and tensile strength perpendicular to the board surface Scientific and practical significance Scientific significance: The results of the thesis on the characteristics of the microscopic structure, chemical composition, major physical properties of the bark are the scientific basis for the effective use of bark in the wood processing industry The results of the thesis are also the scientific basis for the coming studies on composite technology from bark and wood scraps Practical significance: Preliminary study on the production of Acacia mangium bark-based has a great practical significance in effective use, improving the wood recovery rate and protecting the environment The results of the thesis are the technical basis for the selection of technological parameters of making Acacia bark composite boards used in construction and furniture as insulation, sound absorption which should be environmentally friendly materials New contributions of the thesis This is the first study to make composite boards from A mangium bark in Vietnam The microstructure, physical properties, chemical composition of Acacia mangium bark were determined and they were used for the production of the bark composite Determined the relationship and values of technological parameters of making acacia bark composite boards to meet the quality requirements of construction materials Determined the relationship of the proportion of composite board structure and the mixing ratio between bark chips and wood chips affecting the quality of composite boards Determination of sound absorption coefficient and insulation capacity of acacia bark composite materials as a basis for the use of such materials as sound absorption and heat insulating materials Dissertation layout The thesis was written with 123 pages in total, including 45 pictures and 33 tables, the thesis was prepared as follows: Introduction (5 pages) Chapter 1: General introduction (18 pages) Chapter Theoretical basis(14 pages) Chapter Materials and methods (22 pages) Chapter Results and discussion (61 pages) Conclusions, shortcomings and recommendations (3 pages) Totally, 94 documents were cited within thesis Among them, here were 45 Vietnamese documents and 49 foreign languages documents Chapter LITERATURE REVIEW 1.1 General introduction of composite materials 1.1.1 Composite material: Composite material is a material combined of two or more component materials in order to create a new type of material that is different from the original materials as isolating 1.1.2 Classification of composite materials: polymer composite (PC) materials is classified in two ways based on the characteristics of two phases: the polymer matrix phase: thermoset PC-based materials, thermoplastic PC-based materials; the reinforcement phase: dispersed reinforcement (powder); Short fiber or flake reinforcement; Continuous fiber reinforcement (carbon fiber, glass fiber ); Airpadded or porous; Polymer mixture - polymers 1.1.3 Composite boards made from bark: Composite bark is a type of artificial board product, like particle board Bark composite boards are made from bark chips which may or may not use any artificial composite to be an adhesive 1.2 Overview about research on using bark as composite material 1.2.1 Abroad study Chow and Pickles (1971), Hengst and Dawson, Place and Maloney (1975), Demirbas (2005) studied the coefficient of heat transfer, rate of heat, coefficient of thermal expansion Burrows (1960), Chow (1972, 1975), Wellons and Krahmer (1973), Troughton (1997) concluded that pressed at temperature ≥ 1800oC and the pressure can create bark boards without adhesive based on plasticizing the lighin and the metabolism of extracts like a glue to create the bonds in bark boards [54], [55], [84] Roger Pedieu, Bernard Riedl, André Pichette (2008) investigated the structure of birch bark board with outner layer (35, 40, 45) % with UF glue (UF 11%), inner layer (65, 60, 55) % with UF glue (7% UF), board size (560x460x12) mm, density 0.75 (g/cm3), temperature 180oC, pressing pressure 180 KPa Research has shown that Particle boards have the structure ratio: bark chips / wood chips / bark chips (20/60/20) % for the best mechanical properties [80] Research results of the US Forest Products Laboratory (1971) show that the chemical composition of bark is different from wood in both coniferous and broadleaf trees In broadleaf bark, lignin makes up 40-50%, polysaccharides 32-45%, extracts 510%, inorganic up to 20% Fengel and Wegener (1983) showed that compared to wood, bark has higher swell and lower anisotropic, but the insulation and sound insulation are higher Gireesh Kumar Gupta (2009) studied that bark boards with an expected thickness of 6.25mm and apparent density of 0.8 to 1g / cm3, pressing temperature varying from 170oC to 300oC The results showed that at a temperature higher than 230oC, the surface of the plank is burnt because it reduced the bark's chemical components, adversely affecting the properties of the board Roger Pedieu, Bernard Riedl, André Pichette (2008) studied the use of Birch bark for a 3layer particle board: the inner layer is wood chips, the two outer layers are bark chips, the results show that the generated board achieves some good characteristics like hydrophobic, soundproof and thermal insulation Chow (1975) showed that the phenolic substances in the bark of Douglas Fir and Red Fir can be polymerized at high temperatures Based on the study of heat softening, the heat softening of wood and bark at temperatures below 1800oC the wood and bark will be plasticized This plasticizing effect is very important in setting the parameters The reaction of bark at a temperature greater than 180oC is a partial polymerization and degradation of bark components These thermodynamic reactions are important in the manufacture of bark composite boards 1.2.2 Domestic research Tran Vinh Dieu et al (2003) studied the creation of composite based on PP reinforced with jute yarn The material is made by layering PP-MAPP films and jute yarn according to the design and then pressing on hydraulic presses (flat presses in closed molds) under a pressure of 7MPa for 50 minutes Trieu Van Hai (2016) studied some factors affecting the technology of creating composite materials from bark and polyethylene The author studied characteristics of Acacia mangium bark: average bark thickness of 1.1 cm; the rate of bark accounts for 6.03% of the timber volume; diameter of fiber from bark: 19.7 µm to 21.1 µm; The fiber length varies from 1,056 µm to 1,107 µm and produced the composite material from the bark of Mangrove Acacia and HDPE plastic (WPC) 1.3 Conclude the overview of research issues There are many researches over the world about bark composite boards with or without adhesive Various studies have confirmed the feasibility of using all or part of the bark as a raw material for composite board production Most bark composite boards have low to moderate mechanical and physical properties and this can be improved in further research In Vietnam, studies using bark in general and A mangium bark in particular are not many, especially researches about composite materials like some influencing factors of technology to create composite materials from bark and polyethylene Research to create bark composite materials with good soundproofing and heat insulation used in carpentry and construction Chapter THEORETICAL BASIS 2.1 Bark 2.1.1 Introduction of bark: The bark protects the trunk, stores nutrients, bark thickness will increase with age The ratio of bark to trunk depends on the tree species, age of trees and growth conditions Normally, the amount of bark of the trunk varies from to 15% depending on species and growth conditions The proportion of bark is highest in the branches and tops, accounting for 20-35% 2.1.2 Structure of bark: Bark is the outermost layer of the trunk From the outside into the shell is divided into parts: the epidermis, the epidermis, the posterior ring (the parenchyma layer) and the libe The bark is different from the wood The bark is heterogeneous, composed of two different layers: the inner layer and the outer bark 2.1.3 The chemical composition of bark: Bark is much different in chemical composition to wood Table 2.1 Basic chemical compositions of wood, coniferous bark and broadleaf wood (forestry research journal No 091, Forest Product Research Department, USA 1971) Compositions Lignin% Poly saccarite, % Extracts, % Ash content, % Heartwood Wood Bark 18-25 40-50 74-80 32-45 2-5 5-10 0.2-0.6
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