木材／塑膠複合材料之研究與開發(V)廢棄竹幹、桉木、棕梠粒片與聚丙烯複合板之製作及特性比較

Research and Development of Wood/Plastic Composite Materials (V) Manufacturing and Property Comparisons of Waste Bamboo, Gum Wood, and Palm Particles/PP Composite Boards

彭武財(W. T. Peng) ； 黃國雄(G. S. Hwang)

《台灣林業科學》 11卷3期 (1996/09) Pp. 245-260

https://doi.org/10.7075/TJFS.199609.0245

摘要

本研究主要目的爲探討利用較大形（通過5.0mm篩目）之廢棄竹幹、桉木及棕櫚三類粒片作爲增強基材與聚丙烯爲母料複合而製成厚度9.0 mm，比重0.9及0%、30%、50%、70%粒片含率階之板類之可行性，並同時比較其類間、階間以及同一粒片製成之對照用粒片板、一般之商用木基板甚至針、闊葉材間之特性。
三類複合板之製作工程除了所設計之押擠機模頭不適、必須再敲碎與抄模熱壓之外，一切均極順利推行。粒片與塑膠之結合堅密，毫無剝離或脫落現象出現。其成板之加工如鋸、刨、釘等工程與一般木基板類無異。
由於製板條件之設定過於一致，致使較低之粒片含率階之複合板在其熱壓成板過程中塑膠容易溢流至模外，致使成板之厚度與密度均呈明顯之差異。
對機械特性言之，當粒片含率階之增加而三類複合板之抗彎及螺絲釘保持特性亦隨之而激烈地增加。其中，竹幹粒片者最佳，桉木及棕梠粒片者最差，但其值仍爲普通商用之粒片板及木基板之2-3倍大。此等特性在三種複合板類間及各四種粒片含率階間均有明顯之相互差異。
保釘力及衝擊彎曲吸收能量均隨粒片含率階之增加而減小。兩特性在本試驗範圍內仍較對照用之粒片板以及其他木基板高出2倍或以上。其中竹幹粒片者亦示最佳而桉木粒片者最差。各類間及率階間均有明顯之相互差異（竹幹粒片複合板在吸收能量時其四率階間之差異較不明顯）。
三類複合板之表面硬度幾乎與闊葉樹材者媲美，而高出針葉材及一部份南洋材2-3倍。亦爲竹幹粒片者最佳，桉木粒片者較軟。
24小時吸水率最高者（以70%含粒片率階者爲準）僅爲5.2%，而其厚度膨脹率最高亦不超過l.5%。即約爲其他木基板材之1/10以下。8星期吸水率亦最高爲28.8%，厚度膨脹率約爲5.2%而已。而其他粒片板或木基板材則無法或無從得較。其中，棕梠粒片複合板表現最優，桉木粒片者最差。

關鍵字

纖維質粒片／塑膠複合板 ； 木螺絲釘保持力 ； 保釘力 ； 衝擊彎曲吸能量 ； 長期浸水試驗

並列摘要

This study investigates and evaluates the feasibility and the applicability of using a comparatively larger size of three type particles (waste bamboo, gum wood and palm passing a 5.0-mm mesh) as the reinforcing materials and polypropylene as the matrix to fabricate composite boards of 0.9-cm thickness and 0.9 specific gravity with four levels (0%, 30%, 50% and 70%) of particles. The properties between and among the boards of three types and four levels were compared as well as the properties of particleboards formed from similar particles, commercially produced wood-based panels and some softwood and hardwood.
The fabrication of these composite hoards did not present any problems with the exception of the die which was incapable of molding the extruded molten composites to the desired form and shape. As a result, the composites hade to be broken into smaller pieces, formed into a specially built steel mold, and then, re-hot-pressed to the board size required.
The particles in the composites bonded strongly with the plastic polymer, and there was no peeling or flaking off of pieces found. Sawing, planing, screwing and nailing could be performed similarly as with wood-based panels and solid wood.
Notable variations were found in the thicknesses and the specific gravities between arid among the three types and four levels of composites caused by some of the molten plastic flowing out from the mold during hot pressing.
Increasing the level of particle content greatly improved the flexural properties and the screw-holding ability for all composites, with the bamboo boards showing exceptionally good and the gum wood boards showing poor properties, Overall mean values were 2-3 times greater than those obtained from particleboards and other wood-based panels. These properties also varied significantly between and within the three types and four levels of composite boards.
The values of nail withdrawal and impact bending energy absorption for alt composite boards were negatively correlated with levels of particle content. However, values still were more than 2 times greater than those obtained from other particleboards and wood-based panels. Bamboo boards had the highest value and gum wood boards had the lowest among the test pieces. The variations between and within the three types and four levels of composites were found to be significant (with the exception of the impact bending property of bamboo boards whose variations were not significant).
Face hardnesses of three type composite boards were almost as high as those obtained from hardwood, and were 2-3 times greater than those obtained from softwood and some south sea timbers. The bamboo boards were hardest and gum wood boards were the softest among the test pieces.
The highest 24-hour water absorption value (obtained from the boards with 70% particle content) was only 5.2%, and the thickness swelling was 1.5%. This amount to only about 1/10 the value obtained from the other wood-based panels.
Maximum 8-week water absorption, on the other hand, reached only 28.8%, with thickness swelling at 5.2%. It was impossible to obtain readings from the other particleboards or wood-based panels. The composite boards with palm particles performed best on these properties with those with gum wood particles performed the worst.

並列關鍵字

fibrous particle/plastic composite boards ； screw holding ； nail withdrawal resistance ； bending impact energy absorption ； long-term water immersion test