空心玻璃微珠对聚氨酯泡沫燃烧和力学性能的影响

通过向聚氨酯发泡体系中添加空心玻璃微珠,制备出空心玻璃微珠聚氨酯三相泡沫.研究了空心玻璃微珠添加量、聚磷酸铵(APP)用量、膨胀阻燃体系(IFR)浓度等因素对聚氨酯泡沫燃烧和力学性能的影响.结果表明,单独添加空心玻璃微珠对聚氨酯泡沫的氧指数和水平燃烧速度影响不大.添加APP或IFR后,空心玻璃微珠聚氨酯三相泡沫的阻燃效...     

THIEC改性三聚氰胺甲醛树脂泡沫的制备及其性能表征

首先,采用三-(2-羟乙基)异氰酸脲酯(THIEC)作为增韧剂对三聚氰胺甲醛树脂(蜜胺树脂)进行化学改性,以提高树脂的韧性。然后,将改性蜜胺树脂与表面活性剂、发泡剂、固化剂、成核剂等充分混合搅拌,采用普通热发泡法制得三聚氰胺甲醛树脂泡沫(蜜胺泡沫)。用扫描电子显微镜(SEM)、氧指数仪、万能电子试验机、导热系数仪对蜜胺泡沫的形态结构、阻燃性能、力学性能及热绝缘性能进行了测试和分析。探究了发泡剂、固化剂用量对蜜胺泡沫表观密度及形态的影响。结果表明:当THIEC、发泡剂、固化剂、成核剂的用量依次为蜜胺树脂质量的15%、10%、6%、2%,发泡温度为80℃时,蜜胺泡沫的压缩强度达到150kPa、极限氧指数为34、导热系数为0.027W/(m·K),综合性能良好。     

膨润土对采油泡沫稳定性影响研究

本文以十二烷基硫酸钠与磺酸盐型醇醚阴非离子表面活性剂FP1688作为发泡剂,钠基膨润土和钙基膨润土作为稳泡剂进行泡沫性能测试实验。研究结果表明,磺酸盐型醇醚阴非离子表面活性剂FP1688的发泡性能优于十二烷基硫酸钠,钠基膨润土的稳泡性能优于钙基膨润土。当FP1688的浓度为0. 40%、钠基膨润土的浓度为5%时,稳泡时间大于6000s,发泡体积高于800mL。膨润土对泡沫稳定性影响研究对膨润土稳定泡沫配方体系的研制提供了有益的技术指导,对在低油价下推广应用泡沫驱技术意义重大。     

利用珍珠岩尾粉制备发泡材料

以信阳珍珠岩尾粉、凝灰岩为主要原料,石墨为发泡剂,添加适量废玻璃粉、添加剂,在不同的温度下烧制成发泡材料.利用热分析仪分析了混合料的发泡温度,用x射线衍射仪、压力试验机等对样品进行结构表征和性能测试.结果表明:珍珠岩尾粉凝灰岩发泡材料合适的发泡温度为930?.保温时间为30min,样品密度为0.43g/cm3,抗压强度...     

用新型发泡剂--氢化混合稀土制备泡沫铝的研究

研究了混合稀土的氢化工艺和以其作为一种新型发泡剂制备泡沫铝的方法与机制。实验采用熔体发泡法制备闭孔泡沫铝，并与氢化钛(TiH2)作发泡剂制备泡沫铝进行对比实验。结果表明：混合稀土氢化物(REHx)发泡剂的特点是起始发泡温度高，能较显著的延缓气体的释放速率，促使发泡均匀化。经过发泡工艺的优化，以其制备的泡沫铝与用氢化钛(TiH2)做发泡剂相比较，在相同孔隙率条件下，泡沫铝的抗压缩强度有明显提高。     

微波发泡制备三聚氰胺甲醛泡沫塑料及其性能

用三聚氰胺、甲醛和DJ-1型增韧剂在碱性条件下制备了改性三聚氰胺甲醛树脂,将其与表面活性剂、发泡剂、固化剂充分混合搅拌,采用微波发泡炉在一定的功率下进行发泡制备三聚氰胺泡沫塑料.研究了增韧剂的用量、微波功率和发泡时间对泡沫结构和性能的影响.并用光学显微镜、TGA、驻波管对三聚氰胺泡沫塑料的泡孔结构、热学性能和声学性能进行了测试和分析.研究表明:当发泡液质量为50 g时,最佳发泡功率为2 kW,最佳发泡时间为60 s;DJ-1型增韧剂的加入使泡沫的韧性提高,当其质量分数为10％时,泡沫的拉伸强度达到0.112 MPa;泡沫的分解温度约400℃,此时的质量残留率接近60％;泡沫在中高频(≥1 000 Hz)区域的吸声系数高达0.9以上.     

空心玻璃微珠复合聚酰亚胺泡沫的泡孔结构与性能

通过填充空心玻璃微珠,采用预聚法制备了空心玻璃微珠复合聚酰亚胺泡沫,研究了空心玻璃微珠填充量对复合聚酰亚胺泡沫的泡孔结构、热性能和压缩性能的影响规律。结果表明,随着空心玻璃微珠填充量的增加,聚酰亚胺泡沫泡孔结构变得精细,并且热稳定性、玻璃化转变温度和压缩性能都随之提高。当填充量(空心玻璃微珠与均苯四甲酸酐的质量比)达到20%时,泡沫5%热失重温度提高了13.9℃,玻璃化转变温度提高了8.1℃,压缩强度提高了约21%,压缩模量提高了约12%。     

间乙炔基苯偶氮线性酚醛泡沫的结构与性能研究

采用高温化学发泡法制备了一种间乙炔基苯偶氮酚醛树脂泡沫(EPANF).采用傅里叶红外光谱(FTIR)、凝胶渗透色谱(GPC)、光学显微镜、扫描电子显微镜(SEM)、导热系数分析仪、临界氧指数分析仪和热重分析(TG)等表征了间乙炔基苯偶氮酚醛树脂(EPAN)结构和EPANF的泡孔结构、压缩强度、隔热性能、阻燃性能和热性能.研究结果表明,当所用发泡剂含量为18%,泡沫体的表观密度为0.179 g/cm~3时,EPANF泡孔均匀微细,闭孔率高,泡孔平均粒径为350μm左右.随着表观密度增加,泡沫体压缩强度增大,热导率系数增大,隔热性能略有下降,但其临界氧指数变大,阻燃性能提高.当表观密度为0.363 g/cm~3时,EPANF的压缩强度达到最大为5.63 MPa.EPANF的5%和10%热失重温度分别为333、381℃,其700℃的残炭率和1000℃的残炭率分别为65.8%和58.2%,耐热性和耐烧蚀性较普通线性酚醛树脂有明显提高.EPANF作为热结构材料和烧蚀材料有望在航天航空等领域应用.     

水发泡淀粉挤出泡沫的结构与性能

以水为发泡剂,普通玉米淀粉为原料,采用双螺杆挤出机制备淀粉泡沫材料,研究了发泡剂用量及聚乙烯醇的加入量对泡沫材料结构与性能的影响。 用扫描电子显微镜观察了泡沫材料截面的形态,用万能材料试验机测试了泡沫材料的力学性能。 结果表明,水的质量分数为8%时淀粉泡沫径向膨胀率和发泡倍率最高,分别为22倍和17.6倍,压缩模量最高（4.07 MPa）。 加入质量分数10%的聚乙烯醇(PVA)使淀粉泡沫的孔径变大至1.29 mm,壁厚增加至82.43 μm,同时压缩模量增加至9.70 MPa。     

利用水的相变热调控聚丙烯发泡材料的泡孔结构

为了控制发泡体内部泡孔结构,以制备聚丙烯(PP)泡沫为例,提出在CO2作为发泡剂进行物理发泡过程中,以水为助发泡剂,利用其发泡过程中汽化吸热,原位冷却发泡体内部.将PP与聚乙二醇(PEG)熔融共混制备共混物(PP/PEG),PEG的存在赋予了共混物吸水的能力.采用红外线成像仪测试发泡体表层和芯部温度,利用扫描电子显微镜表征了泡孔结构.结果表明,与纯PP发泡体相比,在同样发泡条件下,PP/PEG共混物发泡体内部温度明显降低,内部与表层泡孔结构相近,且发泡倍率提高.进一步分析讨论了PP/PEG共混物发泡体内部温度明显降低的机理.这种方法适用于不同聚合物体系和不同发泡工艺,如:模压、挤出、釜式发泡工艺.     

Glass foam from window panes and bottle glass wastes

Glass foams are building materials that now compete with classic insulating polymeric and fiber materials for thermal enveloping. The low flammability, high chemical durability and thermal stability are distinct advantages over polymeric materials. The present paper proposes the possibility of producing glass foam using two types of recycled glass wastes (window panes and bottle glass) together with plaster wastes from used ceramic casting molds as foaming agent. Optical microscopy, measurements of apparent porosity and density, hydrolytic and chemical stability, as well as thermal conductivity were used in order to characterize the obtained glass foams as insulator materials for the building industry. The apparent porosity of glass foams ranges between 20.19–54.54% when using window glass wastes, and 18.77–51.75% with bottle glass wastes. Thermal conductivity was less than 0.25 W mK-1 for all the studied glasses. The obtained results confirm that there exists an alternative method for producing glass foams, for example, from glass wastes and used ceramic plaster molds, which are utilized as foaming agents with good chemical stability and insulating properties.     

Preparation of wafer-level glass cavities by a low-cost chemical foaming process (CFP)

A novel foaming process-chemical foaming process (CFP)-using foaming agents to fabricate wafer-level micro glass cavities including channels and bubbles was investigated. The process consists of the following steps sequentially: (1) shallow cavities were fabricated by a wet etching on a silicon wafer; (2) powders of a proper foaming agent were placed in a silicon cavity, named 'mother cavity', on the etched silicon surface; (3) the silicon cavities were sealed with a glass wafer by anodic bonding; (4) the bonded wafers were heated to above the softening point of the glass, and baked for several minutes, when the gas released by the decomposition of the foaming agent in the 'mother cavity' went into the other sealed interconnected silicon cavities to foam the softened glass into cylindrical channels named 'daughter channels', or spherical bubbles named 'son bubbles'. Results showed that wafer-level micro glass cavities with smooth wall surfaces were achieved successfully without contamination by the CFP. A model for the CFP was proposed to predict the final shape of the glass cavity. Experimental results corresponded with model predictions. The CFP provides a low-cost avenue to preparation of micro glass cavities of high quality for applications such as micro-reactors, micro total analysis systems (μTAS), analytical and bio-analytical applications, and MEMS packaging.     

The effect of clay on foaming and mechanical properties of glass foam insulating material

In the current study, the main composition was prepared using soda-lime glass with dolomite [CaMg(CO₃)₂] as a foaming agent. The clay powder was added to the main composition in different ratios, and then, the mixtures were shaped by one-axial pressing. Differential thermal analysis (DTA) was used for the determination of crystallization temperatures, and the samples were heated according to the DTA results. Furthermore, heating microscopy was employed for studying the high-temperature behaviours of the mixtures. The samples were characterized using scanning electron microscopy, X-ray diffraction analysis, and comprehensive strength testing. Porosity and bulk density were measured to assess the foaming capability of the mixtures. The results showed that clay addition has a positive role on the mechanical properties of glass foam.     

Increased expansion ratio,cell density,and compression strength of microcellular poly(lactic acid) foams via lignin graft poly(lactic acid) as a biobased nucleating agent

Green and renewable foaming poly(lactic acid) (PLA) represents one of the promising developments in PLA materials. This study is the first to use the lignin graft PLA copolymer (LG‐g‐PLA) to improve the foamability of PLA as a biobased nucleating agent. This agent was synthesized via ring‐opening polymerization of lignin and lactide. The effects of LG‐g‐PLA on cell nucleation induced by the crystallization, rheological behavior, and foamability of PLA were evaluated. Results indicated that LG‐g‐PLA can improve the crystallization rate and crystallinity of PLA, and play a significant nucleation role in the microcellular foam processing of PLA. LG‐g‐PLA improved the foam morphology of PLA, obtaining a reduced and uniform cell size as well as increased expansion ratio and cell density. With the addition of 3 wt% LG‐g‐PLA content, the PLA/LG‐g‐PLA foams increased the compressive strength 1.6 times than that of neat PLA foams. The improved foaming properties of PLA via a biobased nucleating agent show potential for the production and application of green biodegradable foams.     

交联型PVC/TPU轻质材料的制备和表征

以PVC,TPU为主要原料,加入发泡剂AC,交联剂DCP,空心玻璃微珠及其他助剂经模压成型制备了PVC/TPU轻质材料.通过密度以及机械性能测试研究了TPU用量、DCP用量和空心玻璃微珠含量对PVC/TPU轻质材料性能的影响,用红外光谱研究材料基团的变化,通过凝胶含量测试交联体系凝胶量,用SEM扫描电镜表征了材料的泡孔形状、尺寸以及排列.聚酯型TPU能够提高轻质材料弯曲和冲击强度,TPU加入10份时,共混体系的表观密度最低,为0.30 g/cm3.表观密度随着交联剂DCP的添加先降低后增大,红外表征和凝胶含量测试证实轻质材料体系产生了交联结构.空心玻璃微珠的加入,使得PVC/TPU轻质材料的表观密度和综合机械性能提高明显,即使加入20份空心玻璃微珠密度始终小于1.0 g/cm3.SEM表明,DCP的加入使得泡孔更完整且不易破孔,泡孔壁更厚;空心玻璃微珠分布在泡孔壁上,起到引发泡孔和支撑负荷的作用.     

Intrinsic styrene/maleic anhydride copolymer foam; a new green foaming technology

DSM has developed a new foaming technology based on carbon dioxide released via a controlled chemical reaction through catalyzed decarboxylation of SMA, a copolymer of Styrene (S) and maleic anhydride (MA). This carbon dioxide is thus used as an environmentally friendly blowing agent to generate intrinsically foamed SMA-based materials. The modulus of the foam exceeds by far (factor of 2–3) the modulus of common thermoplastic foams based on e.g. PS. The tensile strength is also higher (10%). This opens up many opportunities for SMA foams in structural applications. One example is roofliners. SMA has also been successfully applied as a chemical blowing agent (e.g. in combination with ABS) for the production of a high-density foam on an injection moulding machine or an extruder. In this paper the chemical background, processing, properties and some applications of intrinsically foamed SMA will be discussed.     

热塑性聚氨酯微孔发泡材料的表观密度与其力学性能的关系

用高压CO2流体通过升温发泡法制备了一系列不同表观密度的热塑性聚氨酯(TPU)微孔发泡材料,探究了TPU发泡材料的表观密度与其力学性能的关系.微孔发泡材料的泡孔结构和表皮结构由扫描电子显微镜表征;不同表观密度材料的力学性能利用万能材料试验机和旋转流变仪表征.研究发现:TPU微孔发泡材料的表观密度主要是由材料皮层厚度占比和泡孔层密度决定的,皮层厚度占比越小和泡孔面积占有率越高,泡沫的表观密度越小;微孔发泡材料在线性应变区的压缩模量E与材料表观密度ρ的关系为:E∝ρ1.7,符合泡沫材料压缩模量与表观密度呈指数关系的基本结论;循环压缩实验中,随微孔发泡材料表观密度减小,损耗百分比增大,残余应变减小;流变实验中,微孔发泡材料的模量随表观密度变化没有明显的变化,阻尼因子tanδ随泡沫表观密度变化不呈单一的规律性.同时,阐明了微孔发泡材料的压缩模量E和损耗百分比随表观密度变化的机理.     

Physicochemical control of foam properties

This article summarizes our recent understanding on how various essential foam properties could be controlled (viz. modified in a desired way) using appropriate surfactants, polymers, particles and their mixtures as foaming agents. In particular, we consider the effects of these agents on the foaminess of solutions and suspensions (foam volume and bubble size after foaming); foam stability to liquid drainage, bubble coalescence and bubble Ostwald ripening; foam rheological properties and bubble size in sheared foams. We discuss multiple, often non-trivial links between these foam properties and, on this basis, we summarize the mechanisms that allow one to use appropriate foaming agents for controlling these properties. The specific roles of the surface adsorption layers and of the bulk properties of the foaming solutions are clearly separated. Multiple examples are given, and some open questions are discussed. Where appropriate, similarities with the emulsions are noticed.     

Foaming of trans‐polyisoprene using N2 as the blowing agent

Foaming of trans‐1,4‐polyisoprene (TPI) polymer was carried out through a batch process using nitrogen (N₂) as the blowing agent. TPI vulcanizates having varying crosslink densities were prepared by varying crosslinking agent content and curing time. The vulcanizates were then saturated with N₂ inside a pressure vessel at a pressure of 14 MPa and varying temperatures for 5 hours before effecting the foaming by rapidly quenching the pressure. The effects of varying the crosslinking agent content, silica filler content, and precuring time of the vulcanizates and the effects of varying the gas saturation temperature of foaming on the cell characteristics and physical properties of the foam prepared were investigated. The cells of the TPI foams had a spherical, closed structure. The density, expansion ratio, cell size, cell density, and tensile properties of the foams varied with varying crosslink density of the TPI vulcanizates as well as the saturation temperature of foaming. The important effects of crosslink density and saturation temperature on the N₂ solubility in the TPI matrix and thus on the foam expansion were discussed. The silica filler was found to be acting as a cell nucleating agent and reinforcing filler for the TPI foams.