Foam Rupture by Mechanical and Vibrational Methods

The need to destabilize foams and control their formation arises in many industrial processes. Mechanical foam breakers, mechanical vibration and ultrasonic vibration are examples of physical destructive techniques which do not suffer from the drawbacks associated with the use of chemical antifoams and defoamers. This paper reports on recent studies in this area. Two novel designs of mechanical foam breaker are presented which are superior to traditional foam breakers in controlling unwanted foaming in both bubble columns and stirred vessels. The effectiveness of mechanical and ultrasonic vibrations in destabilizing foams is shown to be governed by vibrational amplitude and frequency, and foam structure. A fundamental understanding of foam destabilization by these physical techniques is crucial to further advancement in the design of efficient and robust foam breakers and the development of enhanced non‐invasive vibrational destructive techniques.     

Instabilities when using a standard (T/3) rushton turbine for stirring as foam disruption (SAFD)

The concept of using the upper stirrer for foam disruption in a bioreactor agitated by multiple impellers has recently been published by Hoeks et al. (1997). This concept, stirring as foam disruption (SAFD), was shown by them to be effective with a range of impellers. However, the commonly used (so‐called) standard Rushton turbine of one‐third the fermenter diameter was not included. This paper fills that important gap. By measuring the foam height, the holdup, the power draw and the velocities of the liquid in the dispersion just below its top surface, it is concluded that the SAFD concept does not work well with the standard Rushton turbine. This is because the amount of broth for which foam can be disrupted is less than that found with all the other impellers tested to date; and even when foam disruption occurs, significant flow instabilities and torque fluctuations are found. Perhaps the poor performance of this impeller, which has been used so frequently in industry and in academic studies, explains why the concept of SAFD was not developed earlier.     

建筑绝热用石墨改性挤塑聚苯乙烯泡沫板的应用及标准解读

挤塑聚苯乙烯泡沫塑料板是一种绝热性能优异、性价比较高的保温材料,其多项性能指标优于其他建筑保温材料。随着我国建筑防火要求的提高,新型保温材料的涌现,市场竞争愈发激烈,挤塑聚苯乙烯泡沫塑料板的市场份额被侵占压缩。为了保有市场份额,应对新材料的冲击与建筑防火要求的提高,研究机构和企业研制出石墨改性挤塑聚苯乙烯泡沫塑料板。本文基于JC/T 2627—2021《建筑绝热用石墨改性挤塑聚苯乙烯泡沫板（GXPS）》标准制定过程,介绍了石墨改性挤塑聚苯乙烯泡沫塑料板的主要性能指标及应用方向,同时指出了该产品当前仍面临的问题,希望为后续研究及相关标准的制定提供参考。     

改性污泥制备泡沫混凝土的可行性研究

由于污泥在建材利用安全性方面存在较多质疑,致使污泥的建材利用一直得不到广泛推广。鉴于此,本实验对剩余污泥进行了改性处理,对改性后获得的泥渣与污泥蛋白液的特性进行了分析,同时对不同泥渣与泡沫掺量下的泡沫混凝土强度和耐火特性进行了研究。结果表明,改性污泥制备泡沫混凝土不存在安全隐患,获得的污泥蛋白发泡剂具有良好的发泡性能。制备的泡沫混凝土具有良好抗压强度、抗折强度,满足行业标准;同时泡沫混凝土的干密度、抗压强度及抗折强度都随着泡沫量的增加而降低;随着污泥渣的增加,泡沫混凝土的干密度和抗折强度下降,抗压强度则呈现先增加而后降低的趋势,在污泥渣质量分数为4%时,抗压强度最佳。耐火试验显示泡沫混凝土具有良好的耐火性能。因此,应用改性污泥制备泡沫混凝土具有较强的可行性。     

再生微粉泡沫保温材料的制备及性能研究

采用湿泡沫拌合法以再生微粉(RP)为主要原料制备了泡沫保温材料,通过测量泡沫的稳定时间、浆体的流动特性与凝结过程,结合试件的抗压强度、干密度、孔隙率以及导热系数等指标,探讨了浆体组成对泡沫存活状态的影响规律以及RP的最大掺量。结果表明:泡沫的稳定性与浆体的黏度、凝结过程存在适宜的匹配状态,当水固比为0.80、浆体黏度为1.7 Pa·s左右、终凝时间小于30 min时,预制泡沫具有较好的存活状态;RP的最大掺量可达70%,所制备泡沫保温材料的抗压强度为1.15 MPa,导热系数为0.118 W/(m·K),符合JG/T 266—2011泡沫混凝土标准A06等级要求。     

Modification of PUR-PIR foams by boroorganic compound prepared on the basis of di(hydroxymethyl)urea

The method for preparation of boroorganic compound with application of N,N′-di(methyleneoxy-3-hydroxypropyl)urea and boric acid has been described. Then, the borate prepared was characterized mainly in the terms of its usability as a polyol component and fire retardant for production of the rigid polyurethane-polyisocyanurate foams. Method of preparation, the determination of foaming parameters, physicomechanical and fire properties of PUR-PIR foams as well as the results of tests have been presented. The recipe for foam preparation was modified by application of physical and chemical method of foaming. On the basis of the results, it was found that application of the new compound in recipe for production of foams is very favourable. The rigid foams obtained are characterized by lower brittleness, higher compressive strength, lower thermal conductivity and considerably lower flammability in comparison with a standard foam.     

玉米基多元醇副产物树脂制备改性聚氨酯泡沫塑料及性能的研究

提出了由玉米基多元醇副产物树脂制备改性聚氨酯泡沫塑料的工艺,分别探讨了玉米基多元醇副产物树脂加入量对聚氨酯泡沫塑料外观、密度及力学性能的影响.当玉米副产物树脂加入量在5份左右时,制备的聚氨酯泡沫塑料可以满足保温材料的相关要求.利用此工艺使聚氨酯泡沫塑料的生产成本大幅度降低,同时也使玉米副产物树脂得到了综合利用.     

复合阻燃法处理泡沫橡胶

采用磷酸盐、尿素、钼酸铵 (即磷 -氮 -钼无卤阻燃体系 )的合理配方及相关药液调制工艺 ,对泡沫橡胶进行上胶处理 ,可以产生良好的协同阻燃效果 ,其阻燃性能远远超过了中国民航的部颁标准 ,具有良好的应用开发价值。     

Effect of the Additive Fire Retardants on the Properties of Rigid Polyurethane Foams,Obtained Using Hydroxyethyl Derivatives of Oxamide and Polymeric 4,4′-diphenylmethane Diisocyanate

The present work investigates the effect of polyol structure and physical addition of boric acid and N,N′-bis(2-hydroxyethyl)oxamide on the properties of rigid polyurethane foams. The product of hydroxyalkylation of oxamide by ethylene carbonate has been used as a polyol component. The new polyol has been foamed using polymeric 4,4′-diphenylmethane diisocyanate, water, and triethylamine. To decrease the flammability of the foams, boric acid, and N,N′-bis(2-hydroxyethyl)oxamide were used as the additive flame retardants. It has been found, that chemical modification of the foam structure by means of oxamide groups decreases their flammability only to a small extent, whereas physical addition of N,N′-bis(2-hydroxyethyl)oxamide does not influence the flammability. However, the addition of boric acid to the foam composition resulted in a distinct decrease of foam flammability, according to the amount of boric acid added. All the foams, modified and nonmodified by boron, have been categorized into flammability class HF-1, according to the applicable standard. The introduction of flame retardants had its impact on the properties of polyurethane foams obtained, as described in this work.     

气相色谱法测定硬质酚醛泡沫制品中游离苯酚含量

建立了以正辛醇为内标物,测定硬质酚醛泡沫制品中苯酚含量的气相色谱分析方法。结果表明,苯酚浓度在0～1.6 g/L范围内呈良好的线性。相关系数（r）大于0.999。方法加标回收率为91.6%～103.9%,相对标准偏差（RSD）小于4%。并且应用该方法对全国不同企业生产的硬质酚醛泡沫板进行检测,取得让人满意的结果。     

阻燃型聚氨酯硬质泡沫塑料的制备

以芳香醇、脂肪醇及溴代醇为主要物料制备了阻燃聚醚，再与固体阻燃剂和液态阻燃剂复配使用，制得阻燃型聚氨酯泡沫塑料。研究了原料种类、发泡剂、异氰酸酯指数、阻燃剂种类等因素对泡沫阻燃性能的影响。结果表明，该阻燃聚醚与复合阻燃剂复配使用，制得的阻燃型聚氨酯泡沫塑料，其氧指数接近29％，压缩强度为270kPa，达到了国家标准GB/T 8624—1997中B2级氧指数的要求。     

慢回弹海绵复原时间的测定方法

阐述了慢回弹海绵的起源、定义、特性及应用领域,详细介绍了国家标准《慢回弹泡沫复原时间的测定》的制订过程和标准内容,研究了慢回弹海绵缓慢复原特性指标-复原时间的测定方法、影响因素和试验方法的精密度与偏差,证明我国的国家标准《慢回弹泡沫复原时间的测定》是合理、可行、实用的,且其精密度与偏差均优于所参考的ASTM标准。     

消泡剂气/液界面膜的性质对其消泡性能的影响

参照消泡试验标准ASTM E2407,评价了硅油类、聚醚酯类及聚醚改性聚硅氧烷类3种消泡剂的消/抑泡性能,并采用LB膜天平,测试了消泡剂对模拟起泡体系扩张模量、扩张弹性和扩张黏度的影响。结果表明,消泡剂分子吸附在气/液界面上,降低了界面膜的弹性,减小了界面膜的强度,使得界面膜厚度变薄,泡沫寿命缩短,从而达到破泡效果;消泡剂存在下的界面膜强度在一定时间内不足以形成稳定的泡沫,从而达到抑泡效果。同种消泡剂,在一定质量分数范围内,随质量分数增加,界面膜扩张模量、扩张弹性均降低,消泡剂消/抑泡性能变好;超过某一质量分数时,界面膜扩张模量、扩张弹性基本保持不变,消/抑泡性能也不再增强。不同种消泡剂,界面膜扩张模量及扩张弹性降低幅度越大,消/抑泡性能越好。因此,扩张模量和扩张弹性可以很好地解释消泡剂的消/抑泡效果。     

有机泡沫导电化处理的溅射法及其设备的研制

泡沫金属是一种多孔三维网状结构的功能材料,泡沫镍作为其典型代表在镍氢电池、冲击减振、高频屏蔽、过滤、催化等高技术领域得到日益广泛的应用。文章设计了连续带状聚氨酯泡沫的表面导电化处理的新工艺和设备,实验表明,磁控溅射法可较好的实现机泡沫卷材的金属化前处理。     

冰箱用硬质聚氨酯泡沫塑料的制备及质量控制

介绍了冰箱用硬质聚氨酸泡沫塑料(简称硬泡)的制备工艺,设计了冰箱用硬泡生产过程中的质量控制流程。实践证明,质量控制流程为保证生产提供了一套较完整、规范的管理方法。     

Main characteristics of foams and a study of the production process of zirconia foam ceramics

Conclusions Some combined studies of the syneresis, resistance, and the rheological properties of two-phase foams used to obtain foam ceramics have been carried out. A series of characteristics have been proposed for the evaluation of the properties of the three-phase mineralized foam ceramics. The connection between the technological and rheological properties of mineralized zircon foam and the connection between the properties of the foams and the foam ceramics obtained from them have been shown.A zircon foam ceramic with a total porosity of 78–90% and an ultimate compressive strength of 2–17 MPa has been prepared.It has been shown that it is possible to obtain a no-shrink (on molding) zircon foam ceramic.Translated from Ogneupory, No. 2, pp. 53–57, February, 1980.     

气相色谱—质谱法测定发泡饭盒中17种邻苯二甲酸酯

目的建立发泡饭盒中17种邻苯二甲酸酯的气相色谱-质谱法(GC-MS)测定方法。方法样品经粉碎后,用正己烷多次提取,采用气相色谱—质谱法分析,外标法定量。结果 17种邻苯二甲酸酯在0.05~2.0μg/mL范围内呈良好线性关系,r0.997;方法检出限为0.02 mg/kg,定量限为0.05 mg/kg,在3个加标水平下,样品平均回收率在97.8%~112.0%,RSD为0.5%~8.8%。结论本方法简单快速、准确、灵敏度高,适用于发泡饭盒中多组分PAEs的同时检测。对采集的33份发泡饭盒样品进行检测,16份发泡饭盒检出邻苯二甲酸二(2-乙基)己酯(DEHP)。     

Experimental Study on Foam Properties of Mixed Systems of Silicone and Hydrocarbon Surfactants

Silicone surfactants are inevitably involved in industrial applications in combination with hydrocarbon surfactants, but properties of the mixtures of silicone and hydrocarbon surfactants have received little attention, especially foam properties of the mixtures. In this study, aqueous solutions of respective binary mixtures of a nonionic silicone surfactant with anionic, cationic, and nonionic hydrocarbon surfactants were prepared for evaluation of their foam properties. Surface tension of aqueous solutions of the mixtures were measured with the maximum bubble pressure method. Foaming ability and foam stability of the mixtures were then evaluated with the standard Ross–Miles method. The findings show that the addition of the silicone surfactant results in a decrease in surface tension for aqueous solutions of the hydrocarbon surfactants. The critical micelle concentration (CMC) of the hydrocarbon surfactants is also changed by the additive silicone surfactant. Additionally, clear foam synergistic effects were observed in the mixtures of silicone and hydrocarbon surfactants, regardless of the ionic types of the hydrocarbon surfactant. The foam stability of the hydrocarbon surfactant was shown to generally improve with the increasing concentration of the silicone surfactant. Even so, aqueous solutions of different ionic hydrocarbon surfactants in the presence of the silicone surfactant will give different foam stabilities. The results of the present study are meant to provide guidance for the practical application of foams generated by the mixtures of the silicone and hydrocarbon surfactants.     

Foaming properties of nonionic detergents

The foam formation and foam stability of aqueous solutions of polyoxyethylene tridecanols, t-octylphenols, nonylphenols, n-dodecanols, and n-octadecanols have been determined as a function of ethylene oxide chain length. In general nonionic detergents form unstable foams; the most stable foams formed by nonionic detergents are comparable to that of sodium dodecylbenzene sulfonate in the absence of foam promoters. In each homologous series of a nonionic detergent the foam formation and foam stability pass through a max at a critical hydrophilic-hydrophobic balance (CHHB). It is shown that the CHHB corresponds to conditions of minimum foam drainage and max resistance to film rupture. Paper presented in part at the 34th National Colloid Symposium, Lehigh University, Bethlehem, Pa., 1960.     

泡沫分离设备的研究进展

作为一种新型分离技术,泡沫分离技术具有设备简单、能耗低、易于操作、低浓度条件下效率高和无污染等优点,该技术在降低表面活性物质分离成本方面具有极大的潜力,在工业上得到了广泛的应用。本工作分析了近年来文献报道中应用于分离回收蛋白质、有机污染物、天然产物、金属离子、微藻等的各种泡沫分离设备,并结合泡沫分离技术的发展历程将其分为传统泡沫分离设备和改进泡沫分离设备。重点阐述了改进泡沫分离设备的作用机理和分离效果,突显泡沫分离技术的重要性。改进型泡沫分离设备在一定程度上提高了分离效果,但依然存在一些问题,如很多设备在提高富集比的同时也降低了回收率。