纳米氧化锌对木塑复合材料抗紫外老化性能的影响

发布时间：2018-07-17 17:12

【摘要】：木塑复合材料(WPC)具有独特的优点(耐腐烛、易加工等),目前主要应用在户外建筑领域,但在长期的户外应用中,其产品抗老化性能较差已成为制约其应用的关键问题之一,因此要使用有效的抗老化剂控制自然环境对木塑复合材料老化性能的影响。本文首先研究不同木粉含量对木塑复合材料性能的影响,在最佳木粉含量范围内以木粉、高密度聚乙烯为主要原料,分别添加氧化锌、纳米氧化锌为抗老化剂,制备木塑复合材料,并对其进行1500h的人工加速紫外老化试验,测试试件老化前后表面颜色、弯曲强度、表面形貌等变化,探讨不同添加量氧化锌和纳米氧化锌对木塑复合材料抗老化性能的影响。本文主要研究内容如下：1.通过添加不同含量(40%, 50%, 60%, 70%, 80%)的木粉制备木塑复合材料,探讨木粉含量对木塑复合材料力学性能和耐腐性能的影响。研究结果表明木粉含量过高或过低都会造成力学性能下降；50%-70%木粉添加量为较理想的选择；随着木粉含量增加,木塑复合材料受白腐菌和褐腐菌腐朽越严重,当木粉含量较高时可以观察到显著腐朽现象。2.分别添加不同含量(1%, 2%, 3%, 4%, 5%)的氧化锌和纳米氧化锌复合制备氧化锌/木塑复合材料、纳米氧化锌/木塑复合材料,氧化锌、纳米氧化锌的添加对复合材料的力学性能产生不利影响,造成力学性能的下降；XRD分析可知,氧化锌、纳米氧化锌确实加入到复合材料中,且其并未影响复合材料的晶型。3.对制得的氧化锌/木塑复合材料、纳米氧化锌/木塑复合材料进行1500h紫外加速老化试验。研究表明,随着老化时间的延长,木塑复合材料老化前后表面色差AE值在增加,添加氧化锌、纳米氧化锌的复合材料其色差值比空白样小；SEM分析表明老化后复合材料的表面出现裂纹, 且随着时间的延长裂纹逐渐加深加大,添加纳米氧化锌裂纹比空白样小,而氧化锌并没有达到此效果；不同配方复合材料老化后弯曲强度均出现不同程度的降低,添加氧化锌、纳米氧化锌弯曲强度下降幅度小于空白样,而不同添加量之间材料的性能相差无几。4. FTIR对老化前后复合材料表面化学变化的分析结果表明,老化过程中复合材料羰基指数持续增加,添加氧化锌、纳米氧化锌羰基指数增加幅度小于空白样；纤维素指数随老化时间的延长而减小,添加纳米氧化锌的复合材料纤维素指数减小幅度小于空白样,而添加氧化锌的复合材料纤维素指数减小幅度大于空白样,这是由于氧化锌的损耗造成的。5.接触角测试表明,氧化锌/木塑复合材料表面的接触角随老化时间的延长呈先增大后减小的趋势,接触角在0-500h内大幅度下降,添加氧化锌的复合材料其接触角下降幅度小于未添加氧化锌的空白样,该阶段材料表面木粉相对含量增加,纳米氧化锌/木塑复合材料的接触角随着老化时间的延长均下降,且添加纳米氧化锌的复合材料的接触角下降幅度与空白样的下降幅度无差别。综上所述,添加氧化锌、纳米氧化锌虽然对材料的力学产生不利影响,但其能延缓复合材料样品表面氧化的发生,从表面褪色程度、弯曲性能、表面化学成分等方面改善木塑复合材料的耐老化性能,比空白样的效果要好,就氧化锌、纳米氧化锌二者相比较而言,纳米氧化锌改善木塑复合材料耐老化性能的效果好于氧化锌。
[Abstract]:Wood plastic composite (WPC) has unique advantages (corrosion resistance, easy processing, etc.). It is mainly used in the field of outdoor building. But in the long term outdoor application, the poor anti-aging property of its products has become one of the key problems that restrict its application. Therefore, it is necessary to use effective anti aging agents to control the aging of wood plastic composite materials. In this paper, the effects of wood powder content on the properties of wood plastic composites are studied. In the optimum range of wood flour content, wood powder and high density polyethylene are used as the main raw material, Zinc Oxide and nano Zinc Oxide are added as anti aging agents, and wood plastic composites are prepared, and the artificial accelerated UV aging test of 1500h is carried out. The effects of different additions of Zinc Oxide and nanoscale Zinc Oxide on the anti-aging properties of wood plastic composites were studied before and after aging. The main contents of this paper were as follows: 1. the wood powder was prepared by adding different content (40%, 50%, 60%, 70%, 80%), and the content of wood powder was discussed. The effects on mechanical properties and corrosion resistance of wood plastic composite material. The results show that the mechanical properties of the wood powder are too high or too low, and the amount of 50%-70% wood powder is an ideal choice. As the content of wood powder increases, the wood plastic composite is more and more corrupt by white rot fungus and brown rot fungus, and can be seen when the content of wood powder is high. Zinc Oxide and nano Zinc Oxide were added with different content (1%, 2%, 3%, 4%, 5%) to prepare Zinc Oxide / wood plastic composite with different content (1%, 2%, 3%, 4%, 5%). The addition of nano Zinc Oxide / wood plastic composite, Zinc Oxide and nano Zinc Oxide were adversely affected on the mechanical properties of the composites, resulting in the decline of mechanical properties; and the analysis of the mechanical properties of the composites. It is known that Zinc Oxide and nano Zinc Oxide do add to the composite material, and it does not affect the crystal type.3. of the composite material and the 1500h UV accelerated aging test of the nano Zinc Oxide / wood plastic composite material. The study shows that the surface chromatic aberration of the wood plastic composites with aging and the aging of the wood plastic composites. The AE value is increasing, adding Zinc Oxide, nano Zinc Oxide composite material is smaller than the blank sample. SEM analysis shows that the surface cracks of the composite material after aging, and with the prolongation of time, the crack gradually deepens and increases, and the addition of nano Zinc Oxide crack is smaller than the blank sample, and the effect is not achieved by Zinc Oxide; the different formula compound is not achieved. After aging, the bending strength of the material decreased in varying degrees, and the bending strength of the nano Zinc Oxide was lower than that of the blank, with the addition of Zinc Oxide, and the properties of the materials between different additions were less than.4. FTIR. The analysis of the surface chemical changes of the composites before and after aging showed that the carbonyl index of the composite was held during the aging process. Adding Zinc Oxide, the increase amplitude of the carbonyl index of nano Zinc Oxide is less than that of blank, and the cellulose index decreases with the prolongation of aging time, and the decrease of cellulose index of the composite with nano Zinc Oxide is less than that of blank sample, and the decrease of fibrin index of the composite material added by Zinc Oxide is greater than that of the blank sample, which is due to the reduction of the fiber index of the composite material of the composite material of Zinc Oxide. The.5. contact angle test caused by the loss of Zinc Oxide shows that the contact angle of the Zinc Oxide / wood plastic composite surface increases first and then decreases with the prolongation of the aging time, and the contact angle decreases greatly within the 0-500h. The contact angle of the composite material added to Zinc Oxide is less than that of the blank blank without the addition of the Zinc Oxide. The contact angle of the nano Zinc Oxide / wood plastic composite decreases with the aging time, and the contact angle decrease of the nano Zinc Oxide composites is not different from that of the blank. In summary, the addition of Zinc Oxide, the nano Zinc Oxide, has a negative effect on the mechanics of the materials. But it can delay the oxidation of the surface of the composite, and improve the aging resistance of the wood plastic composite material from the degree of discoloration, the bending property and the surface chemical composition, which is better than the blank sample. Compared with the Zinc Oxide and nanoscale Zinc Oxide two, nanomi Zinc Oxide improves the aging resistance of the wood plastic composite. The fruit is better than the Zinc Oxide.
【学位授予单位】：东北林业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB332

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