【作者】 朱敏；

【导师】 徐卫兵；

【作者基本信息】 合肥工业大学 ， 材料学， 2010， 硕士

【摘要】 木塑复合材料是由热塑性聚合物与木屑或木粉、植物纤维粉等共混,并添加各种加工助剂,经过高温混炼再经挤出、模压、注射等成型加工而制得的一种环保复合材料。该材料成本低,可广泛应用于建筑、交通、轻工业等部门,具有广阔的市场前景和环保价值。木塑复合材料也有一些不足,木塑复合材料的密度通常为实木材料密度的两倍,而且由于木纤维作为填料加入导致复合材料延展性和冲击强度的下降。本课题主要通过以下几个方面研究并制备了木塑发泡复合材料。(1)通过对比实验研究了PP和PE基木塑复合材料的配方。考察了木粉含量,相容剂含量对复合材料性能的影响,得出的最佳配比为木粉含量为60%,PP-g-MAH含量为8%,。(2)选择合适的发泡剂对上面制得的木塑材料发泡,研究了发泡剂含量,木粉含量对PP和PE基木塑材料的性能影响。结果表明:经发泡的木塑复合材料的密度有了较大的下降,冲击强度得到提高。但是拉伸和弯曲强度会随着发泡剂含量的增加而逐渐降低。发泡剂用量为1.5%时,PP基复合材料的密度降低了17%,冲击强度达到23.3kJ/m2。PE基复合材料的密度降低了18.8%,冲击强度提高了23%。PP基复合材料的发泡剂应选用TA-210,最佳用量为1.5%,PE基复合材料的发泡剂应选用TA-600,最佳用量为1%。木粉含量增加小幅提高了材料的密度,降低了材料的力学性能,但是由于木粉的加入能够大大降低材料的成本,所以可以综合考虑选择木粉的添加量。(3)用自制的发泡母料对比经发泡剂发泡的复合材料,考察了加工条件对发泡材料的性能影响,并用电镜观察了泡孔的结构。结果表明,用发泡母料发泡的复合材料的性能要好于未通过发泡母料发泡的复合材料。发泡剂的用量决定发气量的多少,由于本次实验为微孔发泡,并且发泡剂用量越多,性能下降越厉害,当发泡剂的量为0.5%时为最佳。成核剂的加入,可以增加气泡核的数量,使得泡孔分布均匀,孔径大小相近,复合材料性能上升,但是当其加入量增多时,就会变成填料,导致性能下降。本论文中以8%为佳。发泡木塑的生产中,控制因素很重要。本次实验中根据所用的树脂性能,加工温度180℃为最佳的,而为了保障其不补料,其操作步骤中在射出后先让其样品冷却下来,再储料的方式。通过电镜的观察可知用发泡母料发泡过的复合材料泡孔结构比未经发泡母料发泡的泡孔更加均匀且泡孔直径更小。(4)研究了回收塑料替代新料和竹粉稻壳粉替代木粉的性能。结果显示,在生产条件未改变的前提下采用回收料代替新料制备发泡复合材料是可行的。完全采用回收料替代新料制备的复合材料在力学性能上低于新料制备的复合材料。但性能差别不明显。但用回收料可以减少废旧塑料对环境造成的影响还可以为企业降低生产成本。竹粉替代的复合材料密度最大,弯曲性能最好,但稻壳粉替代的复合材料冲击强度最好。表明本文的配方有着较强的适用性,在实际生产中有着比较好的指导意义。更多还原

【Abstract】 Wood-plastic composites (WPCs) are made from thermoplastic polymer mixed with sawdust or wood flour, plant fiber powder and a variety of processing aids. After a high-temperature mixing, extrusion, molding, injection molding, a kinds of environmentally friendly composite materials can be obtained. Because the material is low cost, WPCs can be widely used in construction, transportation, light industry and have broad market prospects and environmental value. But the Wood-plastic composites have some shortcomings. The density of WPCs is usually twice of wood. As a result of the addition of wood flours, negative effects on ductility and impact strength of the WPCs are observed. The objective of this study is to investigate and produce the foamed wood-plastic composites in the following aspects.(1)Obtained the formula by compared with the WPC made from PP and PE. The effects of wood flour content, compatibilizer content and coupling agent content on the mechanical properties of WPCs are observed. At last we have the optimum ratio of wood flour / MAPP of 60%:8%.(2)Selected the appropriate foam in the optimum ratio of the WPCs. The effects of the foaming agent content, wood flour content on the mechanical properties of the WPCs made from PP and PE are investigated. The results showed that the density of foaming wood-plastic composites have a significant decrease and impact strength is improved. However, tensile and bending strength decreased with increasing the foaming agent content. when foaming agent dosage is 1.5%, the density of the WPCs made from PP reduced by 17%, impact strength is 23.3kJ/m2. And the density of the WPCs made from PE reduce the density of by 18.8%, the impact strength increased by 23%. The WPCs made from PP should be used foaming agent TA-210, and the best dosage is 1.5%. The WPCs made from PE should be used foaming agent TA-600, and the best dosage is 1%. The density of the WPCs has a slightly increase with the addition of wood flours, while the mechanical properties of materials is decreased. But the cost of materials can be reduced significantly ,so we can add a appropriate amount of wood flour.(3)Compared the WPCs using homemade foaming agent and foaming agent, processing conditions on the foaming properties of the material . Observed the foam pore structure by electron microscopy. The results showed that the properties of foam WPCs is better than the WPCs did not foam. The amount of foaming agent is determined the amount of bubble. In our study, the experiment is micro-foam. The more the foaming agent used, the more the mechanical properties decreased. The amount of blowing agent of 0.5% is best. The addition of nucleating agents can increase the number of bubble , make bubble holes evenly distributed and pore size uniform performance, so the mechanical properties of the WPCs can be increased. If nucleating agents increase so much, it will become a filler. Then the mechanical properties will be decreased. In this paper, the amount of 8% is the best. The controlling factor is very important in the production of wood-plastic foam. According to the plastic, the best processing temperature of this experiment is 180℃. But in order to protect their non-feeding, let the sample cool down after the shot, then storage material. Observed by electron microscopy, foam structure of the WPCs using foaming agent is more uniform and the bubble hole diameter smaller than the WPCs without the foaming agent.(4)This paper study the properties of WPCs made from the recycled plastic, rice husk powder or bamboo powder that replace a new plastic and wood flour. The results showed that if the production conditions are not changed, using recycled materials instead of new materials is feasible. The mechanical properties of WPCs made from recycled plastic is lower than the new. But the difference is not obvious. However, recycled materials can reduce the waste plastics in the environmental and can also reduce production costs . The WPCs made from bamboo powder has the highest density and the bending strength. The WPCs made from rice husk powder has the best impact strength. This Show that the formula has a strong applicability and has a good guidance in the actual production.更多还原