共查询到20条相似文献,搜索用时 656 毫秒
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采用聚醚多元醇、多亚甲基多苯基多异氰酸酯(PAPI)、泡沫稳定剂、催化剂、高效阻燃剂、发泡剂、含溴环氧树脂等原料通过一步法制备了聚氨酯硬质泡沫材料,研究了不同含溴环氧树脂添加比例的聚氨酯硬质泡沫材料的压缩强度和阻燃指数。结果表明,随着含溴环氧树脂添加量的增加,压缩强度出现先增加后减少的趋势。在含溴环氧树脂添加量占白料总质量10%时,压缩性能最佳;随着含溴环氧树脂添加量的增加,聚氨酯硬泡的极限氧指数呈上升趋势;高效阻燃剂用量可以使改性聚氨酯硬泡极限氧指数得到显著增加,达到30%以上。 相似文献
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采用一步法制备了聚氨酯硬质泡沫材料,通过改变原料组分中聚醚的组成、异氰酸酯指数、阻燃剂用量、水的用量、交联剂的种类,分别考察了其对双组份聚氨酯硬质泡沫材料性能的影响。结果表明,组合聚醚羟值黏度对制品性能起关键作用,化学发泡剂水的添加量需要严格控制,提高液态添加型阻燃剂含量能够提高制品氧指数,但同时会降低制品力学性能,三乙醇胺作为交联剂制品综合性能好。制备得到了最佳的组合配方,制备出了硬度大、尺寸稳定性好、性能优异的聚氨酯硬质泡沫材料,完全可以应用在保温工程的施工作业中。 相似文献
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对聚氨酯泡沫材料与聚苯乙烯泡沫材料在室内设计中的应用进行对比。结果表明:随着密度的增加,聚氨酯泡沫材料和聚苯乙烯泡沫材料的压缩强度均逐渐提高,当两种材料密度相同时,聚氨酯泡沫材料的压缩强度略低于聚苯乙烯泡沫材料;随着密度的增加,聚苯乙烯泡沫材料的导热率逐渐增大,聚氨酯泡沫材料的导热率先减小后增大。采用一氟三氯甲烷作为聚氨酯泡沫材料的发泡剂,其导热率明显低于聚苯乙烯泡沫材料,在保温效果上优势显著。当处于相同的吸水条件,聚氨酯泡沫的保温性能更优异。仿真分析表明,使用聚氨酯泡沫材料较聚苯乙烯泡沫材料的节能效果更明显。 相似文献
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采用异氰酸酯、聚酯多元醇、发泡剂(水)等原料通过一体发泡成型技术制备出一种新型的三明治泡沫夹心复合材料。利用热重分析、扫描电子显微镜等对不同水含量(质量分数分别为0、0.5 %和1.0 %)的硬质聚氨酯泡沫材料的泡孔直径、密度、热导率、压缩性能、三点弯曲和热力学性能等做了研究,进而确定提高硬质聚氨酯性能的最佳工艺。结果表明,随着水含量的增加,硬质聚氨酯泡沫材料泡孔直径增大,密度变小,热导率降低,保温性能提高,而压缩性能和三点弯曲却呈下降趋势;综合考虑硬质聚氨酯泡沫材料泡孔结构和良好的保温隔热及弯曲等力学性能,其最佳含水量为0.5 %。 相似文献
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以镍渣和废玻璃作为主要原料,使用Na2CO3为发泡剂,采用模具装填法来烧制泡沫玻璃.研究了镍渣的掺量、发泡剂掺量、发泡温度和发泡时间对泡沫玻璃的气孔结构和相关力学性能的影响.研究表明:镍渣掺量减少,Na2CO3掺量增加和发泡温度的升高,均会降低泡沫玻璃的体积密度,提高样品的平均气孔直径;镍渣掺量对泡沫玻璃的组成成分和晶体种类没有明显的影响;以20%镍渣和80%玻璃粉为主料,5%~7%Na2CO3为发泡剂,在发泡温度870 ℃下保温60 min,可以制备出气孔率为85.14%,体积密度为0.3715 g/cm3,抗折强度为2.062 MPa,平均气孔直径在3.13 mm的镍渣基泡沫玻璃. 相似文献
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Michael Hajimichael Annette Lewis Dave Scholey Clive Simmonds 《Polymer International》1986,18(5):307-311
The development of low toxicity rigid epoxy foams as an alternative to polyurethane foams for electronics encapsulation is described. The basic foam components - epoxy resin, hardener, accelerator, blowing agent and surfactant - are blended to form a two part system which is mixed and foamed when required. Each foam component is selected for its contribution to the foaming reaction and the final foam properties. The balance of component miscibility, viscosity, reaction rate and exotherm determine foam quality. Foam properties are affected by (1) density (2) cell structure and (3) the molecular structure of the reactants. Initial foam development utilised epoxy/amine chemistry and produced two foams, Feldex F3 and F4. Subsequently, use of a more reactive polymercaptan hardener improved foam strength and process times, resulting in Feldex F5 and F6 which have been used successfully to prepare quality mouldings and encapsulated electronics. Recently, development has been extended to new areas of application, e.g. high temperature foams. The mechanical, electrical, thermal and chemical properties of the best epoxy foams have been evaluated; selected results are reported. The epoxy foams developed offer low density, high strength, low dielectric constant and loss tangent, high volume resistivity, good thermal insulation, low corrosivity and low toxicity. In addition, epoxy foams soften in acetone, an advantage over their polyurethane counterparts since encapsulated electronics may be retrieved without employing corrosive solvents. (Feldex is a registered trade mark of THORN EMI Electronics.) 相似文献
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《Journal of the European Ceramic Society》2014,34(10):2443-2452
Herein an alternative approach was considered for addressing one difficulty of ceramic foams that the foam slurry with a high content of bubbles which were obtained via direct foaming, cannot maintain well for a long time at room temperature. It is fascinating that the foam slurry mentioned above could stably mold and dry at room temperature, based on an animal protein as foaming agent, kaolin, talc powder and alumina as raw materials, alpha-tricalcium phosphate prepared via co-precipitation as curing agent, and hydrophobic activated carbon powders as stabilizing agent. Effects of the calcination temperatures, the contents of alpha-tricalcium phosphate and activated carbon powder on microstructures, crystal phases, compressive strength and open porosities of ceramic foams were studied systematically. The results indicated that ceramic foams with a high open porosity and uniform pore distribution and sizes sought for application in catalysts supports, could be produced by adjusting these parameters. 相似文献
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传统的泡沫玻璃是在废玻璃中加入发泡剂以760℃以上发泡制的,此方法不仅耗能大、污染重,而且泡沫玻璃耐热温度过低(T≤450℃)。在不添加任何发泡剂下,微波直接加热水玻璃(Na2O3.2SiO2)发泡制备低密度泡沫保温材料;成型的泡沫材料以强酸H+置换Na+,泡沫材料的耐温由450℃提高到1000℃;新工艺降低能源消耗,提高了耐热温度。水玻璃添加少量硅酸铝纤维,不仅能改善泡沫保温材料的隔热性能,同时提高材料的力学性能。水玻璃模数为3.2,硅酸铝纤维含量为1.35%时,保温材料的导热系数为0.064Wm-1K-1;保温材料的抗压强度最高可达0.64MPa。 相似文献
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Polyurethane foams are well-known optimal thermal-insulating materials, which have good thermal insulation performance, high strength, and lightweight properties. Here, we describe a chlorine-free and fluorine-free polyurethane chemical foaming agent (CFA-1) that can react with isocyanate to release CO2 gas and foam polyurethane. We systematically studied its application performance in the field of polyurethane spraying by substituting the current most advanced and environment-friendly physical foaming agent 1-chloro-3,3,3-trifluoroprop-1-ene in different proportions. The results show that highly competitive mechanical properties lead to economical, environment-friendly, and efficient features. The lower thermal conductivity, more compact and smaller bubble structure, and excellent compression strength were achieved by tuning the proportion of CFA-1 from 20% to 60%. Thus, a promising material system was established for the development of the rigid polyurethane foam industry. 相似文献
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以环氧树脂E⁃44作为基体树脂、聚甲基氢硅氧烷(PHMS)为发泡剂、N⁃氨乙基哌嗪(N⁃AEP)为固化剂,采用常温发泡工艺,制备具有良好力学性能及泡孔结构的环氧树脂泡沫,研究各配方组分以及发泡方式对泡沫发泡行为以及压缩性能的影响。结果表明,PMHS含量对泡沫发泡行为有重要影响,需要严格控制,含量超过3 %会较大幅度增大泡孔直径,降低泡孔密度,恶化泡孔结构。同时纳米二氧化硅、甜菜碱(CAB⁃35)以及聚硅氧烷⁃聚氧化烯烃共聚物(DH212)等组分对泡沫的泡孔结构和力学强度都有比较大的影响。 相似文献
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基于红外光谱分析和反应过程树脂黏度及泡孔结构的变化, 说明了三聚氰胺和甲醛为主要原料制备热固性泡沫的机理, 物理发泡过程还发生交联固化, 不同条件下制备不同泡孔大小和长径比的泡沫。为获得轻质、降噪和回弹好的发泡材料, 设计了正交实验优化工艺, 得到最佳工艺为:发泡液黏度1500 mPa·s, 树脂液、表面活性乳化剂、正戊烷发泡剂、固化剂质量配比为50:2:16:4, 微波加热60 s, 制得密度5 kg·m-3的密胺泡沫。 相似文献