可膨胀石墨对吸油型聚氨酯泡沫性能的影响

以聚醚多元醇、亲油性二元醇、三乙烯二胺、辛酸亚锡、有机硅匀泡剂、去离子水、可膨胀石墨(EG)、三(2-氯乙基)磷酸酯(TCEP)、甲苯二异氰酸酯(TDI)为原料制备了阻燃吸油型聚氨酯泡沫,研究了EG用量对该阻燃型聚氨酯泡沫的泡孔结构、吸油性能和阻燃性能的影响。结果表明:随着EG用量的增加,聚氨酯泡沫的吸油性能呈下降趋势;EG和TCEP并用可以产生协同阻燃效应,聚氨酯泡沫的极限氧指数最高可达36%。     

PVA纤维改性酚醛泡沫的研究

为了改善酚醛泡沫的性能,选用聚乙烯醇(PVA)纤维作为酚醛泡沫的增强材料,研究了不同PVA纤维含量和长度对酚醛泡沫的泡孔结构、压缩性能、弯曲性能的影响。结果表明,PVA纤维可以有效改善酚醛泡沫的力学性能和泡孔结构,随着PVA纤维含量的增加,酚醛泡沫的力学性能呈现先增大后减小的趋势。当PVA纤维的用量为酚醛树脂质量的3%时,酚醛泡沫的力学性能达到了最大值,泡孔结构达到了小且均匀的状态。PVA纤维的长度对酚醛泡沫的泡孔结构也有一定的影响,当PVA纤维长度为6 mm时,酚醛泡沫具有最好的泡孔结构,但PVA纤维长度增加时,酚醛泡沫的压缩性能、弯曲性能减小。     

邻甲苯二胺聚醚对硬质聚氨酯泡沫发泡工艺及性能的影响

邻甲苯二胺(OTDA)聚醚是一种特种硬泡聚醚。该聚醚具有自催化活性,可以少用或不用催化剂,减少了VOC排放,符合绿色环保要求;探讨了OTDA聚醚对全水自催化硬质聚氨酯泡沫的工艺和性能影响。实验结果表明,OTDA聚醚对全水硬质聚氨酯泡沫的自催化能力随其用量的增加明显加快,泡沫密度逐渐降低;随着OTDA聚醚用量增加,泡沫的抗压强度增大,阻燃性略微增加,尺寸稳定性增大;同时,闭孔率逐渐升高,导热系数逐渐降低。     

基于大豆蛋白的高回弹聚氨酯泡沫塑料的制备及性能研究

以大豆分离蛋白、高活性聚醚、聚合物多元醇、交联剂、发泡剂、泡沫稳定剂和混合异氰酸酯为原料,自由发泡、常温熟化制备了大豆蛋白基高回弹聚氨酯软泡。研究了大豆蛋白质(SPI)对聚氨酯泡沫物理性能、力学性能、孔结构和热性能的影响。结果表明:SPI添加量对泡沫物理和力学性能影响最大。随着SPI含量增加,泡沫的密度、尺寸稳定性提高,压陷硬度和舒适因子提高增大;回弹率下降,断裂伸长率减小,而拉伸强度先增大后减小。SPI能够提高聚氨酯的热稳定性,但最好低于150℃使用。     

零ODP值发泡剂对硬质聚氨酯泡沫的泡孔结构和导热系数的影响

以聚醚多元醇、聚合MDI为基础原料体系,用ODP值为零的不同发泡剂制备了密度约为31 kg/m3的喷涂聚氨酯泡沫。研究了4种ODP值为零的物理发泡剂HFC-365mfc、HFC-365/227、CP和化学发泡剂K10对泡沫泡孔结构和导热系数的影响,并与HCFC-141b、水发泡剂及其混合体系进行了对比。通过泡沫导热系数、闭孔率测定与扫描电子显微镜等测定,探讨了导热系数与泡孔结构之间的内在关系。研究结果表明,较小的泡孔直径和均匀的泡孔结构有助于降低泡沫导热系数。导热系数随着发泡剂气相导热系数增加而增大。     

细小泡孔结构木塑泡沫材料的制备及形态研究

采用带有超临界流体注入装置的单螺杆挤出发泡系统制备了微孔木塑泡沫材料.所制备的木塑泡沫材料的平均泡孔直径小于50 μm,泡孔密度大于106个/cm3.对于木塑泡沫材料,随着木纤维含量的增加,泡孔平均直径减小、泡孔密度减小、泡沫密度增加、体积膨胀率降低.     

柔性酚醛泡沫塑料的制备

研究了端氨基聚醚改性酚醛树脂,并制备了柔性酚醛泡沫塑料。讨论了氨基聚醚用量对泡沫密度、掉渣率、压缩强度和吸水率的影响。结果表明相对分子质量5 000的氨基聚醚改性效果优于相对分子质量2 000的氨基聚醚。当T5000质量分数为8%时(相对酚醛树脂的质量),固化剂加入16%,匀泡剂加入3%,发泡剂加入10%进行发泡,泡沫掉渣率比未改性泡沫减少41.6%,压缩强度提高29.1%,吸水率降低23.7%。电子扫描显微镜显示氨基聚醚改性酚醛泡沫的泡孔直径较小,孔与孔分布更紧密、均匀,闭孔率较高。     

硅橡胶泡沫泡孔结构与压缩应力松弛性能的相关性

中国工程物理研究院的丁国芳等人研究了氧化锌晶须对硅橡胶泡沫泡孔疏密程度及其对材料力学性能的影响,研究了泡沫密度和混合泡孔结构对材料的压缩应力松弛性能的影响。结果表明,随着氧化锌晶须用量的增加,泡孔疏密程度在增大,硅橡胶泡沫材料拉伸强度和扯断伸长率也在变大。硅橡胶泡沫密度在0．56—0．58g／cm^3范围内时压缩应力松弛性能最佳;在相对密度不变的情况,具有混合泡孔结构的硅橡胶泡沫材料的压缩应力松弛性能更好。     

羟基改性的多壁碳纳米管接枝聚氨酯泡沫的制备及性能研究

采用原位聚合法制备了表面羟基化多壁碳纳米管（MWCNT）接枝聚氨酯(PU)泡沫复合材料。采用超声处理使MWCNT在聚醚多元醇中均匀分散,原位聚合可以改善MWCNT与PU材料间的界面效应。结果表明,当MWCNT含量小于0.4 %（质量分数,下同）时,PU泡孔形态稳定,分布均匀且泡孔尺寸较小,并观察到泡孔壁网状结构间出现膜状结构;当MWCNT含量大于0.6 %时,泡孔尺寸明显变大甚至出现泡孔塌陷;复合材料的回弹性、拉伸强度和断裂伸长率均随MWCNT含量的增加呈先增加后降低的趋势;复合材料的溶剂吸附能力随MWCNT的引入对不同溶剂产生了不同的影响,极性溶剂水的吸附摩尔数随着MWCNT含量的增加而降低,非极性溶剂石油醚的变化规律则相反。     

硅橡胶泡沫泡孔结构与压缩应力松弛性能的相关性

中国工程物理研究院的丁国芳等人研究了氧化锌晶须对硅橡胶泡沫泡孔疏密程度及其对材料力学性能的影响,研究了泡沫密度和混合泡孔结构对材料的压缩应力松弛性能的影响。结果表明,随着氧化锌晶须用量的增加,泡孔疏密程度在增大,硅橡胶泡沫材料拉伸强度和扯断伸长率也在变大。硅橡胶泡沫密度在0．56—0．58g／cm^3范围内时压缩应力松弛性能最佳;在相对密度不变的情况,具有混合泡孔结构的硅橡胶泡沫材料的压缩应力松弛性能更好。     

PP/超临界CO2连续挤出发泡成型

以超临界CO2为发泡剂,在连续挤出发泡过程中研究了超临界CO2用量对高熔体强度均聚聚丙烯(PP)发泡成型过程的影响.随着超临界CO2用量的增加,发泡挤出机口模压力降低,试样发泡倍率降低,泡孔尺寸变小,泡孔密度提高.在w(CO2)为3%,5%时,得到发泡倍率最高为13左右的PP发泡材料.w(CO2)为7%,发泡温度为12...     

硅藻土填充聚氨酯硬泡的性能研究

用硅藻土粉体作为填料,采用全水发泡剂自由发泡制备了聚氨酯硬泡。通过热重分析（TGA）、扫描电子显微镜（SEM）、氧指数仪和万能实验机,研究了硅藻土对聚氨酯硬泡热稳定性、泡孔结构、极限氧指数（LOI）和力学性能的影响。结果表明,硅藻土使聚氨酯硬泡的孔径和密度增大,能提高聚氨酯硬泡的热稳定性、LOI、强度和模量。     

聚乳酸/塑化聚乙烯醇合金开孔发泡行为研究

以聚乳酸(PLA)为基体,加入不同含量的塑化聚乙烯醇(CPVA),通过熔融共混法制备PLA/CPVA合金样品。以超临界CO₂为物理发泡剂,采用釜压发泡和粒子沥滤法成功制备出PLA/CPVA合金开孔泡沫。结果表明,随着CPVA含量的增加,PLA的结晶温度下降,结晶度先上升后下降,熔体黏弹性改善;随着CPVA含量的上升,PLA/CPVA合金开孔泡沫的发泡倍率先减小后逐渐增大,开孔率逐步提高;当CPVA含量为50%(质量分数,下同)时,PLA/CPVA合金开孔泡沫的发泡倍率为23.1倍,开孔率达到了91.6%。     

Physical properties of water‐blown rigid polyurethane foams containing epoxidized soybean oil in different isocyanate indices

To explore the potential of isocyanate usage reduction, water‐blown rigid polyurethane foams were made by replacing 0, 20, and 50% of Voranoll® 490 in the B‐side of the foam formulation by epoxidized soybean oil (ESBO) with an isocyanate index ranging from 50 to 110. The compressive strength, density, and thermal conductivity of foams were measured. The foam surface temperature was monitored before and throughout the foaming reaction as an indirect indication of the foaming temperature. Increasing ESBO replacement and/or decreasing isocyanate index decreased the foam's compressive strength. The density of the foam decreased while decreasing the isocyanate index to 60. Further decrease in isocyanate index resulted in foam shrinkage causing a sharp increase in the foam density. The thermal conductivity of foams increased while decreasing the isocyanate index and increasing the ESBO replacement. Mathematical models for predicting rigid polyurethane foam density, compressive strength, and thermal conductivity were established and validated. Similar to compressive strength, the foaming temperature decreased while decreasing the isocyanate index and increasing the ESBO replacement. Because of the lower reactivity of ESBO with isocyanate, the rate of foaming temperature decrease with decreasing isocyanate index was in the order of 0% > 20% > 50% ESBO replacement. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Water-blown rigid and flexible polyurethane foams containing epoxidized soybean oil triglycerides

Both rigid and flexible water-blown polyurethane foams were made by replacing 0–50% of Voranol® 490 for rigid foams and Voranol® 4701 for flexible foams in the B-side of foam formulation by epoxidized soybean oil. For rigid water-blown polyurethane foams, density, compressive strength, and thermal conductivity were measured. Although there were no significant changes in density, compressive strength decreased and thermal conductivity decreased first and then increased with increasing epoxidized soybean oil. For flexible water-blown polyurethane foams, density, 50% compression force deflection, 50% constant force deflection, and resilience of foams were measured. Density decreased first and then increased, no changes in 50% compression force deflection first and then increased, increasing 50% constant force deflection, and decreasing resilience with increase in epoxidized soybean oil. It appears that up to 20% of Voranol® 490 could be replaced by epoxidized soybean oil in rigid polyurethane foams. When replacing up to 20% of Voranol® 4701 by epoxidized soybean oil in flexible polyurethane foams, density and 50% compression deflection properties were similar or better than control, but resilience and 50% constant deflection compression properties were inferior. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

不同改性方式对发泡剂在铝熔体中分散性的影响

研究了4种不同改性方式对发泡剂在铝熔体中分散性的影响。结果表明：采用TiB2粉末和AlSi合金粉末混合改性发泡剂时,随着TiB2和AlSi含量的增加得到的泡沫铝样品裂纹明显减少、泡体趋向均匀,但孔隙率逐渐降低。相比较而言,混合改性法比溶胶包覆改性法制备出的泡沫铝结构均匀,裂纹要少。     

Foaming of rigid PVC/wood‐flour composites through a continuous extrusion process

The effects of chemical foaming agent (CFA) types (endothermic versus exothermic) and concentrations as well as the influence of all‐acrylic processing aid on the density and cell morphology of extrusion‐foamed neat rigid PVC and rigid PVC/wood‐flour composites were studied. Regardless of the CFA type, the density reduction of foamed rigid PVC/wood‐flour composites was not influenced by the CFA content. The cell size, however, was affected by the CFA type, independent of CFA content. Exothermic foaming agent produced foamed samples with smaller average cell sizes compared to those of endothermic counterparts. The experimental results indicate that the addition of an all‐acrylic processing aid in the formulation of rigid PVC/wood‐flour composite foams provides not only the ability to achieve density comparable to that achieved in the neat rigid PVC foams, but also the potential of producing rigid PVC/wood‐flour composite foams without using any chemical foaming agents.     

Effects of parameter changes on the structure and properties of low‐density polyethylene foam

Several parameters, such as crosslinking agent concentration, blowing agent concentration, and temperature, were varied to evaluate their effects on the structure and mechanical properties of low‐density polyethylene (LDPE) foams. Dicumyl peroxide (DCP) was used as crosslinking agent, while azodicarbonamide (ADC) was utilized as the blowing agent at different levels. The formulations were prepared by using a thermostatically controlled heated two‐roll mill and foamed by using a compression molding technique via a single‐stage foaming process at three foaming temperatures (165, 175, and 185°C). The resultant LDPE foams were characterized and found to have a closed cell structure. The density and gel content increased proportionally with crosslinking level, whereas density decreased when ADC level and foaming temperature were increased. Another characteristic evaluated was the foam cell size decreased when the crosslinking level and foaming temperature were increased. In contrast, increasing the ADC concentration only gave a maximum cell size increase up to 6 phr that decreased when 8 phr of ADC was used. Results also indicated that compression stress increased proportionally with DCP level and decreased when ADC concentration and foaming temperature were increased. Impact studies on the prepared foams showed that their ability to absorb impact energy decreased with increasing crosslinking level, foaming temperature, and blowing agent concentration. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers     

Rigid polyurethane foams made from high viscosity soy‐polyols

This study investigated the physical properties of water‐blown rigid polyurethane (PU) foams made from VORANOL®490 (petroleum‐based polyether polyol) mixed with 0–50% high viscosity (13,000–31,000 cP at 22°C) soy‐polyols. The density of these foams decreased as the soy‐polyol percentage increased. The compressive strength decreased, decreased and then increased, or remained unchanged and then increased with increasing soy‐polyol percentage depending on the viscosity of the soy‐polyol. Foams made from high viscosity (21,000–31,000 cP) soy‐polyols exhibited similar or superior density‐compressive strength properties to the control foam made from 100% VORNAOL® 490. The thermal conductivity of foams containing soy‐polyols was slightly higher than the control foam. The maximal foaming temperatures of foams slightly decreased with increasing soy‐polyol percentage. Micrographs of foams showed that they had many cells in the shape of sphere or polyhedra. With increasing soy‐polyol percentage, the cell size decreased, and the cell number increased. Based on the analysis of isocyanate content and compressive strength of foams, it was concluded that rigid PU foams could be made by replacing 50% petroleum‐based polyol with a high viscosity soy‐polyol resulting in a 30% reduction in the isocyanate content. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

蒸馏水含量对三明治结构硬质聚氨酯泡沫性能的影响

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 %。