粉煤灰空心微珠改善聚合物材料性能的试验研究

粉煤灰空心微珠是从热电厂粉煤灰中精选出来,并进行了除铁、除碳、去杂质等工艺处理而得到的一种新型多功能材料.它可以作为填料填充到聚合物材料中,并改善复合材料的性能.本文中研究了空心微珠作为聚丙烯和硬质聚氯乙烯树脂的填料时,对复合材料综合性能的影响.所用粉煤灰空心微珠颗粒的粒径是2μm和5μm.研究结果表明,当空心微珠填充量在0～30%(质量分数)之间时,空心微珠/PP复合材料的常温和低温下的缺口冲击强度、拉伸性能、弯曲性能都显著提高,复合材料的热性能同时也得到了提高.此外,还研究了空心微珠/UPVC复合材料的流变性能,超细空心微珠加入到硬质PVC管材中,可以明显改善PVC硬管的加工流动性能,显著缩短塑化时间,降低最大扭矩.     

粉煤灰微珠含量与粒径级配比对环氧树脂基复合材料弯曲性能的影响

对粉煤灰空心微珠/环氧树脂复合材料进行了弯曲试验,研究了微珠粒径、含量以及级配比例对复合材料弯曲性能的影响,并通过弯曲断口微观形貌分析了内在机理。结果表明,空心微珠的加入对粉煤灰空心微珠/环氧树脂复合材料的弯曲强度影响很大。随空心微珠含量的增加,复合材料的弯曲强度呈现先升高后下降的趋势,填充量为15wt%时,复合材料的弯曲强度最大;随空心微珠粒径的减小,复合材料的弯曲强度随之提高,小粒径微珠对环氧树脂复合材料弯曲强度的提升效果更好;空心微珠级配填充环氧树脂复合材料的弯曲强度主要受级配微珠中小粒径微珠含量的影响,小粒径微珠的比例越大,弯曲强度越高。     

空心粉煤灰对铁氧体-炭黑/水泥基复合材料吸波性能的影响

通过改变空心粉煤灰微珠、铁氧体、炭黑的配比,分析了影响混凝土电磁吸收效能的主要因素,并探讨了空心粉煤灰微珠、铁氧体和炭黑的加入对水泥基复合材料电磁吸收性能的影响机制。结果表明:8~18GHz频率范围内,空心粉煤灰微珠是影响水泥基复合材料吸波性能的最主要因素,最佳水平组合为20wt%铁氧体、20wt%粉煤灰、10vol%炭黑,-10dB吸收带宽可达10GHz且明显优于无粉煤灰样品,其机制在于空心粉煤灰微珠的掺入同时改善了材料表面透射性能和介电损耗。     

环氧树脂复合材料的制备及隔声性能

以硅烷偶联剂改性的空心玻璃微珠(HGB)为功能填料,端羧基液体丁腈橡胶(CTBN)为增稠剂和增韧剂,环氧树脂为基体,甲基六氢苯酐为固化剂,2-乙基-4-甲基咪唑为促进剂,通过自转/公转搅拌机将混合物混匀、脱泡处理,再经过改变温度的分段固化技术制备了环氧树脂/端羧基丁腈橡胶/空心玻璃微珠(EP/CTBN/HGB)复合材料,并研究了复合材料的隔音性能。实验结果表明,CTBN和HGB均能提升EP材料的隔音性能,CTBN填充量为12%的EP/CTBN比纯EP的平均隔音量高115%,而填充30%HGB的EP/CTBN/HGB复合材料的平均隔音量又较EP/CTBN提高了30%。在填料和CTBN的添加量及试样厚度均相同的条件下,添加空心玻璃微珠的环氧基复合材料的隔音性能优于实心玻璃微珠复合材料。     

粉煤灰空心微珠改性环氧树脂

综述了以一级粉煤灰空心微珠作为填料加入E51环氧树脂对其进行改性的制备以及其粘结性、抗冲击性和耐冲蚀磨损性的试验过程,总结了在制备和试验过程中重点应注意的一些问题。以低分子650聚酰胺树脂作为固化剂改善环氧树脂固化后的韧性不足问题;通过KH550硅烷偶联剂对粉煤灰空心微珠表面进行处理,加强了其与树脂基体的有效结合;消泡剂的使用和低真空搅拌基本解决了树脂基体的气泡问题,空心微珠在树脂基体中的有效均匀分散是制备过程的关键以及性能研究的前提。     

空心玻璃微珠填充环氧树脂复合材料力学性能

对不同填充质量比的改性空心玻璃微珠(HGB)/环氧树脂复合材料进行了拉伸、压缩准静态实验。研究了改性空心玻璃微珠不同填充量对复合材料密度、弹性模量、拉伸强度和压缩强度的影响, 并分析其应力松弛。实验发现, 材料的各项数据随填充比增加均有所降低。空心玻璃微珠的填入使材料表现出脆性破坏, 但破坏前有较大的变形, 破坏后回弹率大, 说明玻璃微珠的填充增强了材料的弹性。HGB/环氧树脂复合材料具有明显的应力松弛现象, 且填充比越高, 应力松弛速率越大, 可见HGB/环氧树脂复合材料具有明显的黏弹性。      

纳米Mg(OH)_2包覆粉煤灰空心微珠复合粉体的制备及表征

为了解决粉煤灰空心微珠白度不高的问题,以粉煤灰空心微珠煅烧样为原料,以NaOH和MgSO_4为包覆剂,采用非均匀形核法制备了一种纳米Mg(OH)_2包覆粉煤灰空心微珠复合粉体材料;采用白度仪、粒度仪、比表面积仪、X-射线衍射仪(XRD)、扫描电子显微镜(SEM)对复合粉体进行表征;研究不同工艺条件对复合粉体白度的影响。结果表明:当包覆量(Mg(OH)_2与粉煤灰空心微珠质量之比)为50%,包覆剂双加,反应温度为80℃时,空心微珠白度由27.1%提高至51.2%,粒径D98由60.81μm增大至66.72μm,比表面积由4.512 m~2/g增大到31.697 m~2/g。XRD、SEM测试结果表明:空心微珠表面包覆了纳米片状Mg(OH)_2。该复合粉体有望应用在塑料填料和污水处理领域。     

碳纤维/碳纳米管-环氧树脂复合材料的耐老化性能

将环氧树脂基体与氨基化碳纳米管(MWNTs)复合,制备了碳纤维/氨基化碳纳米管-环氧树脂(CF/MWNTs-EP)复合材料。表征CF/MWNTs-EP三相复合材料的断面,并在标准条件下测试其冲击、拉伸等力学性能,研究了耐老化性能。结果表明:氨基化碳纳米管的加入明显提高了材料的耐盐雾性、耐热氧老化性和耐湿热性能。氨基化碳纳米管的加入改善了纤维与基体树脂间的界面性能,同时,促进了环氧树脂的固化,降低孔隙率,导致耐老化性能显著提高。当MWNTs-NH2的添加量(质量分数)为1.0%时,在72h和168h不同盐雾时间下,三相复合材料的耐盐雾老化性比CF/EP复合材料分别提高了61.8%和67.5%。在48h、96h和168h热氧老化时间下,三相复合材料的耐热氧老化性比CF/EP复合材料分别提高了43.5%、48.5%和41.7%。在72h和168h不同湿热时间下,三相复合材料的耐湿热老化性比CF/EP复合材料分别提高了52.8%和60.0%。     

环氧树脂复合泡沫塑料的制备及其拉压性能

使用万能试验机对粉煤灰微珠/环氧树脂复合泡沫塑料进行拉伸和压缩实验,并用扫描电镜(SEM)观察其断面形貌,研究了微珠含量、微珠粒径以及级配比例对复合泡沫塑料拉伸和压缩性能的影响。结果表明,随着微珠含量的增加复合泡沫塑料的拉伸和压缩强度都表现出先升高后下降的趋势,且在填充量为15phr时达到最大,其拉伸强度和压缩强度比纯环氧树脂分别提高了9.15%和6.86%。在填充量相同的条件下,微珠的粒径越小复合泡沫塑料的拉伸和压缩强度越高。填充小粒径微珠(20μm)比填充大粒径微珠(250μm)复合泡沫塑料的拉伸强度和压缩强度分别高158.41%和19.96%,拉伸模量和压缩模量分别高32.77%和73.59%。不同粒径微珠级配填充环氧树脂复合泡沫塑料的拉伸和压缩性能主要受小粒径微珠含量的影响,小粒径微珠含量越高其拉伸和压缩强度越高。     

空心微珠-碳纤维共混改性聚酰亚胺复合材料的摩擦学性能

通过模压成型制备了碳纤维与空心微珠共混改性的聚酰亚胺复合材料,采用MRH-3型摩擦磨损试验机研究了空心微珠含量、滑动速度及载荷对复合材料摩擦学性能的影响,并对其磨损形貌及机制进行了分析.结果表明:空心微珠-碳纤维/聚酰亚胺复合材料摩擦学性能优于其单独填充的聚酰亚胺基复合材料;空心微珠含量对共混改性的复合材料摩擦系数影响不大,但其磨损率随着空心微珠含量的增加先减小后增大;15％空心微珠-10％碳纤维(质量分数)共混增强的复合材料的减摩耐磨性能最佳;随着滑动速度提高,空心微珠-碳纤维/聚酰亚胺复合材料的摩擦系数下降,磨损率增大;空心微珠-碳纤维/聚酰亚胺复合材料摩擦系数随着载荷增加先下降后上升,而磨损率则随着载荷增加而增大;空心微珠-碳纤维/聚酰亚胺的主要磨损机制在较低载荷时为磨粒磨损,在较高载荷时为粘着磨损和磨粒磨损.     

空心微珠填充聚丙烯复合材料的显微原位拉伸试验观察分析

无机刚性空心微珠颗粒填充聚丙烯材料的研究结果显示, 空心微珠颗粒的加入可以同时改善其韧性、 强度和刚性。本文中采用显微原位拉伸试验, 对空心微珠／聚丙烯复合材料试样受拉伸过程中裂纹的产生、 发展、 终止和材料的破坏行为进行了动态原位观察分析。试验结果表明, 分散相颗粒能有效地引发大量微小裂纹, 吸收大量能量, 并可以成功阻碍小裂纹的扩展, 使裂纹不致形成破坏性开裂, 改善复合材料的韧性, 并使复合材料的强度同时得到提高。该试验结果为无机刚性颗粒在聚合物中作用的能量耗散理论提供了有力的试验支持。      

Synthesis of polypropylene fiber/high-calcium fly ash geopolymer with outdoor heat exposure

Solar energy is an important source of renewable and sustainable energy. Thailand is near the equator and thus experiences hot weather throughout the year. The average maximum temperature is 35 °C and can reach 40 °C in the summer time. This outdoor heat exposure (OHE) was, therefore, used for the curing of a polypropylene (PP) fiber fiber-reinforced high-calcium fly ash geopolymer composite, in order to reduce energy consumption. Fly ash is an abundant solid waste generated from the coal-power generation process. In this research, a high-calcium fly ash was used as a source material for the geopolymer synthesis. PP fiber was also incorporated in the composites to improve tensile characteristics and control crack development. The results show that the incorporation of PP fiber in composites led to improved tensile strength, crack control, and resistance to acid solution. OHE could thus be used as an energy source for the heat curing of high-calcium fly ash PP-fiber geopolymers, resulting in a strong matrix.     

Synthesis of fly ash particle reinforced A356 Al composites and their characterization

A356 Al–fly ash particle composites were fabricated using stir-cast technique and hot extrusion. Composites containing 6 and 12 vol.% fly ash particles were processed. Narrow size range (53–106 μm) and wide size range (0.5–400 μm) fly ash particles were used. Hardness, tensile strength, compressive strength and damping characteristics of the unreinforced alloy and composites have been measured. Bulk hardness, matrix microhardness, 0.2% proof stress of A356 Al–fly ash composites are higher compared to that of the unreinforced alloy. Additions of fly ash lead to increase in hardness, elastic modulus and 0.2% proof stress. Composites reinforced with narrow size range fly ash particle exhibit superior mechanical properties compared to composites with wide size range particles. A356 Al–fly ash MMCs were found to exhibit improved damping capacity when compared to unreinforced alloy at ambient temperature.     

稻壳粉/PP复合材料的力学性能

制备了稻壳粉/聚丙烯(PP)复合材料,分析了稻壳粉粒度及含量对PP复合材料力学性能的影响,用扫描电镜(SEM)对稻壳粉/PP复合材料拉伸断面进行了分析。结果表明,稻壳粉粒径和含量对PP复合材料性能有一定影响,稻壳粉粒径为245μm的PP复合材料有较好的综合力学性能;随着稻壳粉含量的增加,PP复合材料拉伸强度及断裂伸长率下降,稻壳粉含量为30%时,复合材料弯曲强度和模量均有最大值。稻壳粉含量较低时,其在PP中分散较好,与PP相容性好,复合材料为韧性破坏;稻壳粉含量较高时,稻壳粉有集聚现象,与PP相容性较差,材料的性能较低,复合材料为脆性破坏。     

石墨烯微片/聚丙烯导热复合材料的制备与性能

通过熔融共混法制备了两种不同型号石墨烯微片（GNPs）填加的GNPs/聚丙烯（PP）导热复合材料,研究了GNPs型号（KNG180,KNG150）和含量对其导热性能、密度、结晶性能和热稳定性能的影响。结果表明,KNG180 GNPs/PP复合材料密度高于KNG150 GNPs/PP,同时KNG180对提高聚丙烯结晶度的效果优于KNG150。随着石墨烯微片含量的增加,两种复合材料导热系数均明显增大,而且KNG180填充的复合材料导热性能明显优于KNG150;当KNG180的添加量为60%（质量分数）时,GNPs/PP复合材料的导热系数从纯聚丙烯的0.087 W/（m·K）提高到1.32 W/（m·K）,提高了14倍多。石墨烯微片的加入显著提高了聚丙烯的热稳定性,当KNG180或KNG150的质量分数为10%时,聚丙烯达到最大热失重速率时的温度从345.1 ℃分别提高到374.6 ℃和397.9 ℃,但是当石墨烯微片超过一定含量时,热稳定性会下降。     

PP-g-Si与KH550对聚丙烯/滑石粉体系的增容效果

硅烷接枝聚丙烯（ＰＰ－ｇ－Ｓｉ）对聚丙烯／滑石粉（ＰＰ／Ｔａ）混合体系有一定的增容作用,可使复合材料的力学性能得以提高,占复合材料总质量３．５％的ＰＰ－ｇ－Ｓｉ（相当于含硅烷０．２％）对ＰＰ／Ｔａ体系的增容效果与含０．８％（质量分数）的ＫＨ５５０的增容效果相当,ＫＨ５５０对复合材料中聚丙烯（ＰＰ）的结晶熔融行为基本上无影响。而ＰＰ－ｇ－Ｓｉ能进一步使材料中ＰＰ的结晶峰温和熔融峰温提高。     

Comparative analysis of wear behavior of garnet and fly ash reinforced Al7075 hybrid composite

Al7075 hybrid composites reinforced with varying weight percentage (0 wt.%, 5 wt.%, 10 wt.%, 15 wt.%) of each of garnet and fly ash were fabricated and characterized for their comparative wear assessment. The sliding wear test was conducted on a reciprocating tribometer in dry medium under the working conditions of applied normal load (2 N, 4 N, 6 N, 8 N), sliding velocities (0.04 m/s, 0.08 m/s, 0.12 m/s, 0.16 m/s), sliding distance (20 m, 40 m, 60 m, 80 m) and working temperature (25 °C, 50 °C, 75 °C, 100 °C). The experiments were performed as per steady‐state condition and Taguchi (L₂₅) orthogonal array design to evaluate specific wear rate of the Al7075 hybrid composites. The finding of results indicated that the wear rate was decreased with the increase in the filler content in both the case of garnet and fly ash reinforced Al7075 hybrid composites. The results from Taguchi experiments suggested that the filler content and load were the most significant factors affecting wear behavior of composites while temperature and sliding distance are the least significant factors. Also, the garnet reinforced Al7075 hybrid composite indicated less specific wear rate as compared to that of fly ash reinforced Al7075 hybrid composite.     

粉煤灰增强MC尼龙复合材制备与性能研究

为提高MC尼龙的综合性能,在己内酰胺熔融单体中加入粉煤灰,通过碱催化阴离子聚合反应制备粉煤灰增强尼龙复合材料(FMCPA),采用扫描电镜和拉伸实验对复合材料的显微组织进行了观察和分析,并对其力学性能和摩擦性能进行了测试.结果表明,原状粉煤灰经活化处理后变得均匀细小,但与基体间存在明显的界面空隙,而经活化偶联处理的粉煤灰均匀分布在复合材料中,与尼龙基体的界面结合良好.复合材料的拉伸断面有明显的牵引痕迹,粉煤灰颗粒起到钉紧作用.粉煤灰质量分数较低时,尼龙复合材料以粘着磨损为主,伴有磨粒磨损;随着粉煤灰质量分数的增加,磨粒磨损加重.粉煤灰的加入提高了复合材料的力学性能,同时改善其耐磨损性能,当粉煤灰质量分数为20%时复合材料的综合性能最好.     

Effects of surface treatments and size of fly ash particles on the compressive properties of epoxy based particulate composites

Particulate reinforcements for polymers are selected with dual objective of improving composite properties and save on the total cost of the system. In the present study fly ash, an industrial waste with good properties is used as filler in epoxy and the compressive properties of such composites are studied. Particle surfaces are treated chemically using a silane-coupling agent to improve the compatibility with the matrix. The compressive properties of these are compared with those made of untreated fly ash particulates. Furthermore properties of fly ash composites with two different average particle sizes are first compared between themselves and then with those made using the as-received bimodal nature of particle size distribution. Microscopic observations of compression tested samples revealed a better adherence of the particles with the matrix in case of treated particles and regards the size effect the composites with lower average particle size showed improved strength at higher filler contents. Experimental values of strengths and modulii are compared with some of the theoretical models for composite properties.