Syntactic Foam Preparation

The syntactic foams are made by simply mixing the micro- or macrospheres into a catalyzed resin until the desired consistency is obtained. In most cases the materials are mixed to a putty-like state, or, if a casting material is desired, to a state in which the material can just be cast. The usual ratio of filler to resin is approximately 60% filler by volume (23). 

A propeller-type mixer is satisfactory for preparing experimental batches of syntactic foam, but on a commercial scale a kneader-type 

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The problem of ozone depletion considered in the Montreal Protocol is discussed in detail. Qiapter 8 considers methods of manufacture, including molding methods, spraying, frothing, laminating, structural foam molding, syntactic foam preparations, and foam-in-place techniques. Chapter 9 on sources of information covers journals, manufacturers bulletins, technical conferences and their published proceeding, seminars and workshops, standardization activities, trade associations, consultants, and information centers, and books. 

Proceedings of the Workshop on Acoustic Attenuation of Materials Systems, prepared by the National Materials Advisory Board (NMAB) Committee on Structural Application of Syntactic Foam, NMAB-339, 1978, 147 pp. 

The same thermosetting polystyrene SMP was used in this study. In addition to the 40% by volume of glass microbaUoons, 0.15% by volume of multiwalled carbon nanotubes was also added, which was the same as in Reference [38]. The multiwaUed carbon nanotubes (Cheap Tubes Inc.) have a density of 2.1 g/cm, diameter of 20-30 nm, and length of 20-30 pm. Similar to Reference [38], a two-step procedure was used to prepare the syntactic foam. First, the carbon nanotubes were added to Part A of the polymer. The mixture was mixed with the assistance of an ultrasound mixer for 30 minutes at a frequency of 20 kHz (Sonics Vibracell VC 750W) and a three-roll mill for one pass (NETZSCH type 50) (see Rgure 3.26). Second, microballoons and hardener (Part B of the polymer) were added to the carbon nanotube/Part A mixture and mixed with a spatula for 15 minutes. It was then poured into an aluminum mold of... 

A two-step procedure was used to prepare the syntactic foam. First, the carbon nanotubes were added to the resin matrix. The mixture was mixed with the assistance of an ultrasound mixer for 30 minutes at a frequency of 20 kHz (Sonics Vibracell VC 750W) and a three-roll... 

The presence of cells marks the distinctive difference between bulk composite and composite foams. The level of porosity measures the amount of empty space within the matrix and varies with foam density. For the case of syntactic foams, different microstructures or levels of porosity can be created through varying the type and amount of microspheres. Details of the microspheres used by Wouterson et al. (2007b) to prepare the epoxy syntactic foams are listed in Table 2.1. In the fracture toughness assessment under quasistatic loading, SEND specimens were loaded in a three-point bend (3PB) geometry. Due to the difference in density between the various types of microspheres, densities of foams with equivalent amounts of microspheres vary. The difference in density makes the comparison of the properties of foams nonrelevant. In order to compare the performance of foams, the specific mechanical/fracture properties are used. 

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