本文選題：竹塑復(fù)合材料 + 抗氧化劑　； 參考：《中國(guó)林業(yè)科學(xué)研究院》2017年博士論文

【摘要】：與木材、竹材等實(shí)體天然材料相比,木塑復(fù)合材料(WPC)的耐候性能相對(duì)優(yōu)異,但在溫度和濕度較高的地區(qū),WPC的老化現(xiàn)象也非常嚴(yán)重。WPC耐候性能的優(yōu)劣對(duì)其廣泛應(yīng)用起著重要作用。竹塑復(fù)合材料(BPC)以竹材碎料為增強(qiáng)相或填料,是WPC的重要組成部分。本文以BPC為研究對(duì)象,系統(tǒng)研究抗氧化劑的組合、配比及含量對(duì)BPC抗熱氧老化及其他物理力學(xué)性能的影響;采用噴霧施加技術(shù)將穩(wěn)定的TiO_2溶膠負(fù)載到竹粉或者聚丙烯(PP)表面,重點(diǎn)研究施加工藝和納米TiO_2添加量對(duì)BPC氙燈加速老化和自然老化性能的影響。作為對(duì)比試驗(yàn),還研究了幾種商業(yè)抗老化劑對(duì)BPC性能的影響;采用直接添加表面改性商業(yè)納米顆粒或者以噴霧施加技術(shù)將改性納米顆粒懸浮液負(fù)載到竹粉表面,研究了不同施加工藝及納米顆粒含量對(duì)BPC氙燈加速老化性能的影響;提出一種簡(jiǎn)單快速分離竹材中纖維與薄壁細(xì)胞的物理方法,研究了不同細(xì)胞單元對(duì)BPC氙燈加速老化和自然老化性能的影響。論文主要結(jié)論如下:(1)氧化誘導(dǎo)時(shí)間(OIT)可作為WPC抗氧化劑快速篩選的重要指標(biāo)。添加少量的抗氧化劑可顯著提高BPC的OIT,是改善BPC抗熱氧老化能力的有效途徑。添加抗氧化劑可顯著提高BPC在熱烘箱老化過(guò)程中的抗光變色能力、表面抗侵蝕性能以及彎曲性能保留率,同時(shí)降低質(zhì)量損失率。主要原因是抗氧化劑可有效抑制BPC的表面發(fā)生熱氧老化。添加抗氧化劑對(duì)BPC的吸水性能、動(dòng)態(tài)力學(xué)性能以及熱性能影響較小�；诔杀究紤],本研究提出的抗氧化劑體系的優(yōu)化組合參數(shù)為:主抗氧化劑1076與輔抗氧化劑硫代二丙酸二月桂酯(DLTP)組合,配比為2:1,總含量占PP的0.2 wt%。(2)雖然原位合成納米TiO_2的施加工藝可以保證納米TiO_2在BPC中具有良好的分散性,但未能改善BPC在氙燈加速老化和自然老化過(guò)程中的抗光變色能力,并且加劇了老化過(guò)程中BPC的表面侵蝕現(xiàn)象。上述不利影響通常隨著納米TiO_2含量的增加而更加明顯。主要原因是作為催化劑的無(wú)機(jī)酸加速了BPC在老化過(guò)程中的降解。改性竹粉和低溫干燥改性PP工藝均略增加了BPC在老化過(guò)程中的力學(xué)損耗,但高溫干燥改性PP工藝則在一定程度上降低了BPC在老化過(guò)程中的力學(xué)損耗。(3)在竹粉表面原位合成納米TiO_2對(duì)BPC的初始物理力學(xué)性能起著負(fù)面作用,而在PP表面原位合成納米TiO_2則對(duì)BPC的初始物理力學(xué)性能無(wú)不利影響或起到顯著改善作用。低溫干燥改性PP工藝在納米TiO_2含量?jī)H為0.2%和0.5%時(shí),BPC的彎曲強(qiáng)度和模量分別提高近21%和18%,24 h吸水率和吸水厚度膨脹率分別下降近40%和45%。因此,采用低溫干燥工藝在PP表面原位合成納米TiO_2,并且合理控制納米TiO_2的含量,可顯著改善BPC的界面結(jié)合性能。(4)施加少量的商業(yè)抗老化劑,可輕微提高BPC的初始彎曲強(qiáng)度和模量,其中主抗氧化劑1076與輔抗氧化DLTP組合和有機(jī)光穩(wěn)定劑GW-327的效果要優(yōu)于表面未經(jīng)改性的商業(yè)納米ZnO和Ti O_2。同時(shí),抗老化劑對(duì)BPC的吸水性能影響較小。商業(yè)抗老化劑可提高BPC在氙燈加速老化和自然老化過(guò)程中的抗光變色性能,其中抗氧化劑和有機(jī)光穩(wěn)定劑組合的效果最好。同時(shí)抗老化劑可降低BPC在老化過(guò)程的表面侵蝕和力學(xué)性能損失,其中商業(yè)納米Zn O的效果最顯著,但是商業(yè)納米TiO_2的改善作用不明顯。(5)KH-570硅烷和超聲分散協(xié)同作用改性可顯著降低商業(yè)納米TiO_2和ZnO的粒徑分布,并改善納米顆粒在BPC中的分散性。改性納米TiO_2和ZnO的加入顯著提高了BPC的彎曲強(qiáng)度和模量,降低了BPC的吸水性能。當(dāng)納米TiO_2和ZnO含量?jī)H為0.1%并采用噴霧施加方式,BPC的彎曲強(qiáng)度和模量分別提高了23.3%和36.8%,以及28.6%和26.5%。同時(shí),24 h吸水率和吸水厚度膨脹率分別下降了59.7%和66.7%,以及85.2%和52.8%。此外,表面改性商業(yè)納米TiO_2和ZnO還可提高BPC的抗光變色能力,并且在老化初期改性效果更顯著。然而,改性納米顆粒未能顯著改善BPC表面的抗侵蝕性能。雖然老化后,含改性納米顆粒復(fù)合材料的彎曲強(qiáng)度和模量下降率高于對(duì)照樣,但是其絕對(duì)平均值依然高于后者。(6)不同細(xì)胞單元對(duì)BPC的增強(qiáng)作用存在顯著差異,其增強(qiáng)作用大小為:竹纖維楊木纖維(竹纖維+薄壁細(xì)胞)薄壁細(xì)胞。與竹薄壁細(xì)胞/PP復(fù)合材料相比,竹纖維/PP復(fù)合材料的彎曲強(qiáng)度和模量分別提高了26.5%和50.3%,24 h吸水率和吸水厚度膨脹率分別降低了32.8%和24.1%。不同細(xì)胞單元填充PP復(fù)合材料經(jīng)氙燈加速老化和自然老化后,表面顏色均發(fā)生顯著褪色,并且出現(xiàn)一定數(shù)量的裂紋,彎曲性能和儲(chǔ)存模量降低。竹纖維/PP復(fù)合材料在老化過(guò)程中彎曲性能的損失遠(yuǎn)低于竹薄壁細(xì)胞/PP復(fù)合材料。但是后者在老化過(guò)程中的抗光變色性能優(yōu)于前者。因此,合理調(diào)控BPC中竹纖維與薄壁細(xì)胞的比例可改善BPC的耐候性能。綜上所述,通過(guò)施加優(yōu)選抗氧化劑組合不僅可顯著改善BPC的抗熱氧老化性能,同時(shí)還提高了BPC光氧老化過(guò)程中的抗光變色和表面抗侵蝕性能;此外,施加表面改性商業(yè)納米TiO_2和ZnO顆�？梢燥@著提高BPC的力學(xué)性能,降低吸水性;添加有機(jī)光穩(wěn)定劑和合理調(diào)控BPC中竹纖維與薄壁細(xì)胞的比例,也可一定程度上改善BPC的抗光氧老化性能。
[Abstract]:Compared with solid natural materials such as wood and bamboo, wood plastic composite material (WPC) has relatively excellent weatherability, but in areas with high temperature and humidity, the aging phenomenon of WPC is very serious and it plays an important role in the wide application of.WPC weather resistance. Bamboo plastic composite material (BPC) with bamboo material as reinforced phase or filler is the weight of WPC. In this paper, the effects of combination, ratio and content of antioxidants on thermal oxygen aging and other physical and mechanical properties of BPC are systematically studied with BPC as the research object. The stable TiO_2 sol is loaded onto the bamboo powder or polypropylene (PP) surface by spray application technology, and the application process and the TiO_2 addition of nano TiO_2 to the BPC xenon lamp are studied. The influence of accelerated aging and natural aging properties. As a comparative test, the effects of several commercial antiaging agents on the performance of BPC were also studied. Using direct addition of surface modified commercial nanoparticles or spraying technology to load the modified nanoparticle suspension on the surface of bamboo powder, the different application process and nano particle content were studied for B. The effect of the accelerated aging performance of PC xenon lamp, a simple and rapid physical method for separating fiber and parenchyma cells in bamboo is proposed, and the effects of different cell units on the accelerated aging and natural aging properties of the BPC xenon lamp are studied. The main conclusions are as follows: (1) the oxidation induction time (OIT) can be used as an important index for the rapid screening of WPC antioxidants. Adding a small amount of antioxidants can significantly improve the OIT of BPC and is an effective way to improve the ability of BPC to resist heat and oxygen aging. The addition of antioxidants can significantly improve the anti photochromic ability of BPC in the aging process of hot oven, the surface erosion resistance and the retention of flexural properties, and reduce the quality loss rate. The main reason is that the antioxidant can be effective. The addition of antioxidants has little effect on the water absorption, dynamic mechanical properties and thermal properties of BPC. Based on the cost, the optimum combination parameters of the antioxidant system proposed in this study are: the combination of the main antioxidant 1076 and the auxiliary antioxidant thiopropionic acid two propionate (DLTP), with a ratio of 2:1, and the total content of the antioxidant 1076. The amount of 0.2 wt%. (2) of PP (2), although the application process of in situ synthesis of nano TiO_2, can guarantee the good dispersibility of nano TiO_2 in BPC, but it can not improve the anti photochromic ability of the xenon lamp in accelerated aging and natural aging process, and aggravate the surface erosion of BPC during the aging process. The adverse effects are usually along with nanoscale. The increase of TiO_2 content is more obvious. The main reason is that the inorganic acid as the catalyst accelerates the degradation of BPC during the aging process. The modified bamboo powder and the low temperature drying modified PP process have slightly increased the mechanical loss of BPC during the aging process, but the high temperature drying modified PP process reduces the force of BPC in the aging process to a certain extent. (3) in situ synthesis of nano TiO_2 on the surface of bamboo powder has a negative effect on the initial physical and mechanical properties of BPC, while the in-situ synthesis of nano TiO_2 on the PP surface has no adverse effect or significant improvement on the initial physical and mechanical properties of BPC. The low temperature drying modified PP process is bent when the nano TiO_2 content is only 0.2% and 0.5%, the bending of BPC. The strength and modulus increased by nearly 21% and 18%, 24 h water absorption and water absorption thickness decreased by nearly 40% and 45%., respectively. Therefore, nano TiO_2 was synthesized by low temperature drying technology on PP surface, and the content of nano TiO_2 could be controlled reasonably. (4) a small amount of commercial anti aging agent could be applied slightly. The initial bending strength and modulus of BPC, including the combination of the main antioxidant 1076 with the auxiliary antioxidant DLTP and the organic light stabilizer GW-327, is better than the surface unmodified commercial nanoscale ZnO and Ti O_2., while the anti aging agent has little effect on the water absorption of BPC. The commercial antiaging agent can increase the accelerated aging and natural aging of the xenon lamp in BPC. The anti photochromic performance of the process is the best combination of antioxidants and organic light stabilizers. At the same time, anti aging agent can reduce the surface erosion and mechanical properties loss of BPC in aging process, of which commercial nano Zn O has the most significant effect, but the improvement of commercial nano TiO_2 is not obvious. (5) KH-570 silane and ultrasonic dispersion synergy. The modification can significantly reduce the particle size distribution of commercial nanoscale TiO_2 and ZnO and improve the dispersion of nano particles in BPC. The addition of modified nano TiO_2 and ZnO significantly improves the bending strength and modulus of BPC and reduces the water absorption properties of BPC. When the nano TiO_2 and ZnO content is only 0.1% and the spray is applied, the bending strength and modulus of BPC can be obtained. The increase of 23.3% and 36.8%, as well as 28.6% and 26.5%., 24 h water absorption and water absorption thickness expansion rate decreased by 59.7% and 66.7% respectively, as well as 85.2% and 52.8%.. The surface modified commercial nano TiO_2 and ZnO can also improve the anti photochromic ability of BPC, and in the early aging, the modification effect is more significant. However, the modified nano particles can not be used. The corrosion resistance of BPC surface was significantly improved. Although the bending strength and modulus of the modified nano particle composite were higher than the same after aging, the absolute mean value of the composite was still higher than that of the latter. (6) there were significant differences in the enhancement of BPC by different cell units. The enhancement effect was bamboo fiber poplar fiber (bamboo fiber +). Parenchyma cells) parenchyma cells. Compared with bamboo parenchyma /PP composites, the flexural strength and modulus of bamboo fiber /PP composites increased by 26.5% and 50.3% respectively. The water absorption and water absorption thickness of 24 h decreased by 32.8% and 24.1%., respectively, of PP composites filled with the xenon lamp to accelerate aging and natural aging after xenon lamp accelerated aging and natural aging. In the aging process, the loss of flexural properties of bamboo fiber /PP composites is much lower than that of bamboo parenchyma cell /PP composites. However, the photochromic properties of the latter in the aging process are better than those of the former. Therefore, the rational control of bamboo fiber and thinning in BPC is made. The ratio of parietal cells can improve the weatherability of BPC. To sum up, the application of optimal antioxidant combination not only significantly improves the anti thermal oxygen aging properties of BPC, but also improves the anti photochromic and surface anti-corrosion properties of BPC in the light oxygen aging process. Furthermore, the application of surface modified commercial nanoscale TiO_2 and ZnO particles can significantly improve B The mechanical properties of PC reduce water absorption, adding organic light stabilizer and reasonably regulating the proportion of bamboo fiber and parenchyma cells in BPC can also improve the anti photooxidation aging performance of BPC to a certain extent.
【學(xué)位授予單位】：中國(guó)林業(yè)科學(xué)研究院
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB332
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本文編號(hào)：1972234