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DESPITE the quite extensive literature on foam, the mechanism of its formation and decay does not appear to be widely appreciated. Most fundamental research has been orientated towards maximum foam in aqueous solutions, whereas the desire in aircraft engines is for minimum foam in oil ‘solutions’. Further, the numerical results obtained experimentally depend on the details of experimental procedure, which makes correlation of existing data very uncertain.

This paper aims to develope the electromagnetic interference shielding materials with high performance. To develop advanced polymer-based electromagnetic interference shielding materials with rather high temperature stability, good processability and moderate mechanical properties, the authors chose the polyimide (PI) foam as matrix and ferriferrous oxide (Fe₃O₄) as fillers to prepare the composite foams with lightweight and rather good electromagnetic interference shielding performance.

Some polyimide nanocomposite foams with Fe₃O₄ as fillers have been prepared by in situ dispersion and foaming with pyromellitic dianhydride (PMDA) and isocyanate (PAPI) as raw materials and water as foaming agent. By varying the Fe₃O₄ contents, a series of PI/Fe₃O₄ nanocomposite foams with fine microstructures and high thermal stability were obtained. The structure and performances of nanocomposite foams were examined, and the effects of Fe₃O₄ on the microstructure and properties of composite foams were investigated.

This work demonstrates that PI/Fe₃O₄ foams could be fabricated by thermally treating the polyimide foam intermediates with Fe₃O₄ nanoparticles through a blending reaction of precursors. The final PI/Fe₃O₄ composite foams maintained the excellent thermal property and showed a super paramagnetic behaviour, which has a positive effect on the improvement of electromagnetic shielding performance.

In this paper, the effects of Fe₃O₄ on the performances of PI/Fe₃O₄ composite foam were reported. It provided an effective methodology for the preparation of polymer/Fe₃O₄ nanocomposite foams, which hold great promise towards the potential application in the areas of electromagnetic shielding materials.

A series of PI/Fe₃O₄ composite foams with different contents of Fe₃O₄ were prepared by blending reaction of the precursors. The effects of Fe₃O₄ on the structures and properties of PI/Fe₃O₄ composite foam were discussed in detail.

A series of sulfate-based Gemini anionic surfactants were synthesized via etherification, ring opening and sulfation reactions using epichlorohydrin, fatty alcohol, ethylene glycol and chlorosulfonic acid as the main raw materials. Orthogonal experiments for 1,8-bisalkoxymethylene-3,6-dioxin-1,8-octane disulfate were performed on the sulfation reaction to determine the optimal reaction conditions.

A series of sulfate-based Gemini anionic surfactants were synthesized via etherification, ring opening and sulfation reactions using epichlorohydrin, fatty alcohol, ethylene glycol and chlorosulfonic acid as the main raw materials. Orthogonal experiments for 1,8-bisalkoxymethylene-3,6-dioxin-1,8-octane disulfate were performed on the sulfation reaction to determine the optimal reaction conditions. The structures of the intermediate and final products were characterized by FT-IR (Fourier transform infrared spectroscopy analysis), ¹H-NMR (proton nuclear magnetic resonance spectroscopy) methods. The thermal performance of surfactants was analyzed using thermogravimetric analysis (TGA). The thermogravimetric results showed that the sulfate-based Gemini surfactants had good heat resistance (the thermal decomposition temperature of which was in the range of 140∼170?). The Krafft point, surface tension, foaming, Hydrophile–Lipophile Balance Number (HLB), emulsifying, wetting, and lime-soap dispersing performance were measured by visual observation, hanging drop method, aqueous surfactant solution method and Borghetti–Bergman method, respectively. The results have shown that all the sulfate-based Gemini surfactants had good water solubility and lime-soap dispersing ability. When spacer group was -(CH2)2-, with the increase of the carbon chain length from C12 to C14, the micellar concentration critical micelle concentration and surface tension (CMC) gradually increased from 8.25 × 10^–4 mol/L to 8.75 × 10^–4 mol/L and 27.5 mN/m to 30.9 mN/m, respectively. Also, the sulfate-based Gemini surfactants with the different length of the spacer group had a different effect on their performance on foaming properties and foam properties, HLB and emulsifying ability and wetting ability.

In view of the important role of the spacer group and the general use of anionic surfactants in oil fields, this article considers the preparation of a series of sulfate-based Gemini surfactants by changing the spacer group and the chain length of the hydrophobic group and evaluating their surface activity, and finally its Kraffi, on the foam properties, HLB value, emulsifying performance, lime soap dispersing ability etc.

Sulfate-based Gemini surfactants have broad application prospects in the fields of oil and gas exploitation, environmental protection, chemistry and daily chemical industry and so on.

A novel two series of self‐sequestering surfactants have been prepared by the reaction of itaconic acid, phthalic anhydride, citric acid with oxypropylated 1,4‐butane diol and oxypropylated 1,6‐hexane diol. The structure features of these surfactants have been confirmed by IR and ¹H NMR spectra. These surfactants exhibit excellent properties of self‐sequestering. Besides good surface active properties including surface tension, interfacial tension, low foaming, good wetting properties, good stability towards acidic and basic media, emulsifying power and dispresent properties, solubilization properties and good biodegradability, they possess autonomous sequestering ability without any help of additional sequestering agent.

The encapsulation of electronic assemblies within thermoplastic polymers is an attractive technology for the protection of circuitry used in harsh environments, such as those experienced in automotive applications. However, the relatively low‐thermal conductivity of the encapsulating polymer will introduce a thermally insulating barrier, which will impact on the dissipation of heat from the components and may result in the build‐up of stresses in the structure. This paper therefore seeks to present the results from computational models used to investigate the thermal and thermo‐mechanical issues arising during the operation of such electronic modules. In particular, a two‐shot overmoulded structure comprising an inner layer of water soluble and an outer layer of conventional engineering thermoplastics was investigated, due to this type of structure's potential to enable the easy separation of the electronics from the polymer at the end‐of‐life for recycling.

Representative finite element models of the overmoulded electronic structures were constructed and the effects of the polymer overmould were analysed through thermal and thermo‐mechanical simulations. Investigations were also carried out to explore the effect of materials properties on the overmoulded structure.

Models have shown that some power de‐rating of components is required to prevent temperatures exceeding those in unencapsulated circuits and have quantified the benefits of adding thermally conductive fillers to the polymer. Simulations have also clearly demonstrated the benefits of foamed polymers in reducing thermal stresses in the assemblies, despite their poorer thermal conductivity compared with solid polymers.

The paper illustrates the thermal issues affecting the overmoulded electronics and gives some guidelines for improving their performance.

Four series of nonionic copolymer surfactants have been prepared by the free radical copolymerizations of dioctyl itaconate (DOI) with dioxypropylated itaconic acid. Copolymerization reactions were carried out in solution at 70°C using 1mol. percent azopisisoputyronitrile as a free radical initiator. The copolymers were obtained by reprecipitation from petroleum ether (40‐60) and finaly dried in vacuum at 60°C. The structural features of these nonionic copolymer surfactants have been confirmed by IR and ¹HNMR spectra. The surface active properties of these polymers were compared and evaluated, including solubility, cloud point, surface properties, interfacial tension, foaming emulsification and biodegradability. Most of the products are good biodegradable surfactants; which manifested the importance of their application in pollution problems.

In this paper, boric acid was loaded on the surface of expandable graphite (EG), polyvinyl alcohol (PVA) and silane coupling agent (KH550) served as a bridge. The purpose of this study was to improve the flame retardant properties of semi-rigid polyurethane, meanwhile, the mechanical properties of the foam got ameliorated.

PVA was dissolved in hot water. EG was added to this solution. After stirring for 0.5 h at 85°C in ultrasonic agitation, the system was put at room temperature to cool. The silane coupling agent KH550 was added dropwise into the solution system, stirring to fully hydrolyze. Boric acid was added into the system, placing it in an oven at 90°C to dry after filtration. Changing of flame retardant properties and mechanical properties of semi-rigid polyurethane adding modified EG were characterized.

The flame retardant performance of the foam with EG has been improved, whereas the tensile strength decreased with an increase in the content of EG. After adding modified EG, compared to semi-rigid polyurethane with EG, flame retardant performance and tensile strength of the foam improved.

In the study reported here, the surface of EG was modified by boric acid. The modified EG was added into semi-rigid polyurethane foam. The flame retardant performance and tensile strength of the foam after adding modified EG were discussed. Results of this research could benefit in-depth study of the influence of adding modified EG to semi-rigid polyurethane. The study could promote the application of flame-retardant polyurethane foam.

The flame retardant performance and tensile strength of the semi-rigid polyurethane were improved by adding modified EG. The effects of modified EG on the flame retardant performance and tensile strength of semi-rigid polyurethane were discussed in detail.

This article aims to consider the use of high pressure processing in order to gain functional advantages through proteins structure control. High pressure processing has been used to produce high-quality food with extended shelf life and could also be used to modify foods functionality.

The effect of high pressure on protein structure and functionality is looked at and comparisons are made with heat effect in places. β-lactoglobulin and whey proteins are mainly taken as examples.

A controlled partial protein unfolding through mild high pressure processing could lead to a range of intermediate molecular structures. These are distinct from the native and completely unfolded structure and have been referred to as molten globules. The partly unfolded molecular states, hence, are postulated to have increased functionality and could be interesting for the food industry.

The opportunity and challenges represented by these theoretical elements are discussed. In particular, the effect of protein concentration and aggregation is emphasised.

Natural good-quality sources of aggregates are depleting, whereas large amount of reclaimed asphalt pavement (RAP) is produced annually. Safe disposal and use of RAP in the cold in-place recycling (CIR) using foamed bitumen could be sustainable approach where milling and mixing operations are accomplished simultaneously. This will not only help in minimizing contamination (probability) and transportation cost but also reduces the carbon footprints. Therefore, this study aims to investigate the scope of RAP utilization up to 100% and further its effect on the behavior of reclaimed asphalt foamed bituminous mix.

Reclaimed asphalt foamed bituminous mix (FBM) is still a new technique. The evidence of performance of 100% recycled pavement (CIR) is only anecdotal and lacks in systematic guidelines and literatures. Foam binder coating around the aggregates is also a concern. Therefore, this study is mainly emphasized to investigate the scope of RAP use in the FBM up to 100%. RAP content is varied in each trial, i.e. 70, 85, 100 and 0% (only fresh aggregates), to make the FBM. RAP use and its effect on the behavior of FBM in terms of resilient modulus, variation in resilient modulus with curing, rutting performance and the potential of resistance against the moisture damage are addressed.

Considering the laboratory studies, it can be accomplished that mechanistic properties and performance of FBM are largely influenced by RAP material and portray less susceptible characteristics against the moisture damage. FBM containing 70% RAP content exhibits maximum resilient modulus. However, use of RAP up to 100% in FBM is satisfying the minimum required specification.

Overall, the study may be helpful to highway professionals and could generate another possible option of 100% RAP replacing fresh aggregates in the flexible pavements.

Metal foams are a structural and functional composite materials that have received wide attention due to their specific structures and properties. The aim of this study is to investigate the mechanical properties of syntactic foam by using expanded silica gel with the spacer technique.

In this research paper, the vacuum casting production method was used to produce metal syntactic foams including AlSi12 and AlSi8Cu3 matrix and expanded silica gel fillers with diameters of 2–4.75 mm and 4.75–5.6 mm.

As a result of the study, it was observed that as the foam densities increased, the compressive strength values of the samples increased due to the increasing volume fraction of the metallic matrix. Samples with the AlSi12 matrix showed higher compressive strength than samples with the AlSi8Cu3 matrix.

The originality of the study is the comparison of two different main matrix alloys (AlSi12 and AlSi8Cu3) and different pores using expanded silica gel.