Development of green composites using thermoplastics and bamboo fiber

以毛竹（中国）和竹（日本）为原料，采用三种方法提取竹纤维。(1)采用常规纤维松脱机进行机械加工。它有一个旋转的钉鼓，里面用的是细竹条。未满一年的竹子适合这种方法。(2)碱（NaOH）处理：首先将竹条浸泡在热碱浴中几个小时，然后进行加工。(3)蒸汽爆炸法：将生竹片置于蒸汽室中，蒸汽室将充满高压的过热蒸汽。然后，蒸汽突然被释放。微细胞爆炸发生在细胞内。然后，用脱模机从蒸汽爆破竹中提取纤维。竹材经碱处理和蒸汽爆破法可得到较长的纤维，机械加工可得到较短的纤维。然而，只要竹子非常年轻，就可以通过混合热塑性（TP）纤维获得足够长的纤维，用于制造无纺布。利用较短的竹纤维以及PP、PE等TP纤维，成功开发了无纺布。可作为绿色复合材料，形成汽车顶棚、后托盘等内部部件。由玉米制成的PIA（聚乳酸）纤维也可以用来代替PP纤维。使用双螺杆挤出机将短于50mm的纤维与TP混合，制备绿色复合材料颗粒。为了提高注塑件的拉伸/弯曲强度，竹纤维直径和长径比是一个关键。竹纤维的标称直径应小于0.1毫米，长径比应大于20。通过双挤出路径，竹纤维在复合材料中的长径比减小。竹纤维（50%wt含量）/PP复合材料的最大拉伸强度约为50 Mpa。马来酸改性有利于提高竹纤维绿色复合材料的力学性能。测定了随机竹纤维垫/聚酯复合材料（BFRP）的力学性能。采用RTM（树脂传递模塑）法制备BFRP，碱处理后从MOSO竹中提取长竹纤维。采用梳绒机与打孔机配合制作竹席。垫层非常厚，合成的BFRP强度很低，不足以用于制造小船（5米长）。然后，为了提高竹纤维的分数，将竹席提前压缩并使用。观察到改进后的BFRP的强度足以用于船只。然而，关于吸水率的研究告诉我们要非常重视水。强烈建议在使用过程中进行适当的处理以防止吸水。本研究表明，微纤竹纤维的加入不仅可以提高PIA的力学性能，还可以提高其高温耐热性。短竹纤维可以提高拉伸强度和耐热性，但由于竹纤维的原因，其冲击强度变低。另一方面，如果竹纤维轻微纤化，则冲击强度得到很好的提高。最后，基于PLA的复合材料的机械和热性能有时高于20% wt%的玻璃纤维/ABS复合材料。纤维化竹纤维还可用于制造半导体验证盘。少

Bamboo fibers were extracted from raw bamboo such as Moso (Chinese) and Madake (a typical Japanese bamboo) by following three methods. (1) Mechanical processing by using the conventional fiber loosening machine. It has a rotating nail drum where thin bamboo strips are used. Younger bamboo than one year old is suitable for this method. (2) Alkali (NaOH) treatment: First, bamboo strips are immersed in a hot alkali bath for a couple hours, then, they are machined(3) Steam explosion method: Raw bamboo is set in a steam chamber which will be filled with super heated steam at high pressure. Then, the steam is abruptly released. Micro-cell explosion occurs in cells. Then, fibers are extracted by using the loosing machine from steam exploded bamboo. Relatively long fibers are obtained by the alkali treatment and the steam explosion method while short fibers are extracted when bamboo is mechanically processed. However, long fibers can be obtained enough to be used for fabricating non-woven fa … More brics by mixing thermoplastic (TP) fibers as long as the bamboo is very young. Non-woven fabrics using relatively short bamboo fibers as well as TP fibers such as PP and PE were successfully developed. It can be used as a green composite material to form inner components of automobiles such as ceiling and rear trays. PIA (Poly Lactic Acid) fibers made from corns can also be used instead of PP fibers. Fibers shorter than 50 mm are mixed with TP using a twin screw extruder to fabricate green composites pellets. In order to increase the tensile/bending strengths of the injection molded parts, the bamboo fiber diameter is a key as well as the aspect ratio. Thinner than 0.1 mm is desirable for the nominal diameter of bamboo fibers as well as a high aspect ratio greater than 20. Through the twin extruder path, the aspect ratio of bamboo fibers in a composite decreases. The maximum tensile strength of a bamboo fiber (50%wt content) /PP composite is about 50 Mpa. The maleic acid modification is obliged to increase the mechanical properties of bamboo fiber green composites.The mechanical properties of random bamboo fiber mats/Polyester composites (BFRP) were measured. The BFRP was fabricated by RTM (Resin Transfer Molding) while long bamboo fibers were extracted from MOSO bamboo by the alkali treatment. The bamboo mats were fabricated by using a carding machine in conjunction with a needle punching machine. The mats was very thick and the resultant BFRP had a low strength not enough to use for fabricating small boats (5 m long). Then, in order to increase the bamboo fiber fraction, bamboo mats were compressed in advance and used. The observed strength of the improved BFRP is strong enough to use for the boats. However, the study on water absorption tells us to pay a lot of attention on water. An appropriate treatment to prevent the water absorption during service is strongly suggested.The present study shows that not only the mechanical properties of PIA but also the heat resistance at elevated temperature are well improved due to inclusion of micro-fibrillated bamboo fibers. Short bamboo fibers can enhance the tensile strength and heat resistance, but the impact strength becomes low due to bamboo fibers. On the other hand, if the bamboo fibers are slightly fibrillated, the impact strength is well improved. Finally, the mechanical and thermal properties of the composite materials based on PLA are sometimes higher than those of 20 wt% glass fiber/ABS composite. The fibrillated bamboo fibers are also applied to fabricate the proving disks for semi-conductors. Less