木陶瓷製造條件對其基本性質及石墨化度行為之影響

Abstract

本研究結合木質廢棄物再利用與木質系新素材開發兩目的，嘗試發展以木質材料為原料之木質系新素材「木陶瓷」，即以木質材料與合成樹脂或無機黏結劑製成複合材料後經高溫碳化處理，碳化燒成後所得之碳材料。本研究針對木陶瓷之製備條件與其基本性質及微結構結晶行為進行討論分析，期藉以瞭解木陶瓷之基本性質及新用途發展之可能性。 經針對木陶瓷之製備條件（不同基材組合比例、碳化燒成溫度、昇溫速度等）與其基本性質（比重、收碳率、收縮率、電阻係數、熱輻射係數等）及微結構結晶行為（微結晶面尺寸、晶體層間距離等）進行探討，各實木、粒片板、硬化粒片板及木質膨礦土複合材之碳化物收碳率大致均隨燒成終溫昇高而降低，並依據收碳率變化，歸納出炭化溫度於500℃、800℃、1100℃時，所得碳化物微結構有特殊變化。而各試材碳化物收縮率依燒成溫度、方向不同等有所差異，燒成溫度愈高則收縮率愈增加。實木、粒片板、硬化粒片板及木質材料膨礦土複合材碳化物尺寸收縮率，均隨炭化/碳化/燒成溫度昇高而增加，而不同昇溫速度則對收碳率、收縮率無顯著影響。 硬化粒片板碳化物碳元素含量（C％），於300、400℃有最低值，而後隨著燒成溫度昇高而增加。其電阻係數則隨碳化溫度增加而急速降低，板面平行方向電阻（ρ//）較粒片層積方向之電阻係數（ρ⊥）為低；另含脂率低之試材有較大之電阻係數，含脂率高之硬化粒片板碳化物電阻係數較小。此外，泡桐硬化粒片板、泡桐膨礦土複合材之碳化物熱輻射係數高，為良好之吸熱材料。 木陶瓷試材，實木、粒片板及硬化粒片板之碳化物經X射線繞射之002面繞射峰約出現於22∼23°，隨燒成溫度提高向較大角度集中移動，且相對002面層間距離（d值）變小。木質材料與膨礦土複合之材料燒成後之碳化物經X射線繞射所得002面繞射峰約出現於26°，隨燒成溫度提高向26.5°集中之趨勢。其可能於燒成碳化之過程中，複合材料中之木材因熱解而釋出高分子隨後並鑲入膨礦土之蒙脫石層間，受蒙脫石微結構之八面體所限制。隨著燒成溫度提高，各種熱解之高分子因受矽酸鹽層間距離之限制，致無法形成立體交鏈之碳化物，進而轉成層狀之碳平面結構，並有接近石墨結晶（002）面之繞射角出現。又木質膨礦土複合材之木陶瓷碳微結構中石墨與鑽石結構之吸收峰面積比例，隨著燒成溫度提高而增加，其值自0.13∼1.19，石墨結構（sp2）有增加之趨勢。至結晶構造內結晶面的延伸擴張程度（La值）為0.95∼6.83，當木質材料重量比率較高且燒成溫度高時，所得La值相對較大。 依據各不同製備條件所得之木陶瓷中，以木質膨礦土複合材碳化後之基本性質及結晶行為有明顯異於實木、粒片板、硬化粒片板等之基本性質，其中以石墨化度之行為尤有顯著變化差異，建議未來應可進一步探討木質膨礦土複合材之石墨化度行為、電磁波遮蔽、保溫等功能，繼續新材料之開發與運用。

The purpose of this research is to develop a new composite woody material, called 'woodceramics', by utilizing recycle woody wastes. Woodceramics are components of wood and synthetic resin or the inorganic and procceed with high-temperature carbonization. This research is about real wood, particleboard, compreg particleboard and wood-Bentonite composite carbides’ basic properties and graphitization. To understand the woodceramics and to assess the potential usage of it, the study would focus on analyzing the physical properties (specific gravity, carbide yield, shrinking ratio , resistance coefficient, heat emissivity, etc.) and microstructure crystallization properties(size, distance among layer of crystal, etc.) related to their procedure conditions, such as different proportion of materials, carbonization temperature, intensified speed, etc. The carbide yields in solid wood, particleboard, compreg particleboard and wood-Bentonite composite decreased as carbonization temperature increased, and the microstuctures had significantly change as temperature at 500℃, 800℃, 1100℃. The shrinkage ratio of real wood, particleboard, compreg particleboard and wood-Bentonite composite increased as the carbonization temperature increased. Temperature rising rates were no siginificantly related to carbide yield and shrinkage ratio. Compreg particleboard carbide (C% ) has the minimum value in 300, 400℃, and increased as carbonization temperature raised. The electronic resistance coefficients dropped down as carbonization temperature increasing. The electronic resistance property had direction, and the resistance coefficient in parallel direction is lower than perpendicular direction. The electronic resistance coefficients had opposite relationship with the proportion of PF in impregnated particleboards, lower PF resin contain with higher resistance coefficient, and higher PF resin contain with lower resistance coefficient. Besides, the Fortune Paulownia PF impregnated particleboard and Fortune Paulownia-Bentonite composites carbide had higher radiation emissivity than metal, in the other words, these materials are excellent in heat absorption. The X-ray diffraction spectra's 002 peak of carbide from solid wood, particleboards and impregnated particleboard are nearly appeared in 22∼23°, and the peak angle increased with increasing carbonization temperature, but the d value reduced. The X-ray diffraction spectra's 002 peak of carbide from wood-Bentonite composites are nearly 26°, and increased to 26.5° with increasing carbonization temperature. In other words, the diamond and graphite structure ratio（G/D） in the wood-Bentonite composite's microstructure increased as carbonization temperature increased, the G/D vaule is around 0.13 to 1.19. The extension of the crystallization（La value） is around 0.95 to 6.8, which increased with increasing carbonization temperature. No matter the difference of woodceramics procedure conditions, the wood-Bentonite carbides have signicantly different in both physical and crystallization properties, especially in graphitization properties, with solid wood, particalborads and impregnated particleboard. I would suggest further reseraches on how woodceramics properties in graphitization behavior , electromagnetic wave cover and emissibity etc.