Cloisite* 30B nanoclay

This chapter presents the study of the effect of various micro- and nanofiUers and different curing cycles on resin curing-induced shrinkage. The resin used in the experiments is conventionally used in aerospace and defense apphcations (Kelkar et al., 2006), a two-part toughened epoxy resin, namely SC-15. 3M Glass Bubbles iM16K, Cloisite 20A nanoclay, and Cloisite 30B nanoclay with 0.5, 1, 2, 3, and 5 wt% concentrations were selected as micro- and nanofiUers, respectively. 

Figure 18.3 represents the measured and computed volumetric shrinkage of SC-15 epoxy resin modified with Cloisite 30B nanoclay. It can be noticed that the volumetric shrinkage follows a similar trend as Cloisite 20A nanoclay of reducing shrinkage with increasing concentration. The maximum filler influence of Cloisite 30B (0.128%) on resin shrinkage was found to be at 3 wt% filler content. 

Figure 183 Measured and computed volumetric shrinkage of SC-15 epoxy resin modified with Cloisite 30B nanoclay.

Figure 18.8 represents the volumetric shrinkage of SC-15 epoxy resin modified with 3 wt% of Cloisite 30B nanoclay and cured using different cycles. It can be seen that the case of SC-15 epoxy resin reinforced with 3 wt% Cloisite 30B nanoclay is similar to the case of SC-15 epoxy resin reinforced with 3 wt% Cloisite 20A nanoclay. Both cases demonstrate the increase of shrinkage after postcuring of RT-vitrified... 

The inks are prepared by mixing an epoxy resin (Epon 826 epoxy resin) with dimethyl methyl phosphonate, nanoclay platelets (Cloisite 30b), silicon carbide whiskers (SI-TUFF SC-050), and milled carbon fibers (Dialead K223HM). Further, an imidazole-based ionic liquid is employed as a latent curing agent (Basionics VS03) (31). 

A popular filler in the SMPC world is Cloisite 30B. In the MMT clay manufactured by Southern Clay Products, the particle size distribution is such that 90% of the particles (dry weight) are of less than 13 pm diameter, while 50% of the particles are less than 6 pm and 10% are less than 2 pm [68], This breakdown makes Cloisite in some sense a nanoclay, but in reality still a microclay. TEM images presented by Schulz et al. [68] did indicate 500 nm particles in Cloisite 30B. Cloisite 30B is, however, comprised of platelets that are approximately 120 nm in diameter and as small as 3 nm thick [69]. Under the correct pre-processing conditions, these platelets can be incorporated into polymer networks to varying degrees of uniformity and success at very different size scales. 

TABLE 11.5 LOI Values for Flame Retardant Polyamide-6 in Combination with Cloisite Na+ and 30B Nanoclays and Selected Flame Retardants... 

Cloisite 30B > Cloisite Na" " > commercial nanoclay > pure polyamide-6 For an APP-PER system at most concentrations, the decreasing LOI order is... 

Cloisite 30B > pure polyamide-6 > Cloisite Na" " > commercial nanoclay... 

Cloisite Na+ > Cloisite 30B > commercial nanoclay > pure polyamide-6,6... 

Zein protein was obtained from Zein Protein Corp, Marina, CA, and used as received. Nanoclay (Cloisite 30B), a natural montmorillonite composed of layered silicates and modified with a quaternary ammonium salt was obtained from Southern Clay Products, Gonzales, TX. Other reagents, such as glycerin were obtained from a general chemistry store. 

Incorporation of modified clays into thermosetting resins, and particularly in epoxy35 or unsaturated polyester resins, in order to improve thermal stability or flame retardancy, has been reported.36 A thermogravimetric study of polyester-clay nanocomposites has shown that addition of nanoclays lowers the decomposition temperature and thermal stability of a standard resin up to 600°C. But, above this temperature, the trend is reversed in a region where a charring residue is formed. Char formation seems not as important as compared with other polymer-clay nanocomposite structures. Nazare et al.37 have studied the combination of APP and ammonium-modified MMT (Cloisite 10A, 15A, 25A, and 30B). The diluent used for polyester resin was methyl methacrylate (MMA). The... 

The addition of plasticizer used for the improvement of mechanical properties leads generally to an increase in the oxygen permeability coefficient due to the higher mobility of the polymer chain and higher free volume [102]. On the contrary, the dispersion of nanoclays in PLA makes it possible to divide the permeability coefficient by 2 or 3 depending upon the type of the nanoclays (e.g. organomodified montmorillonite, cloisite 25A or 30B, organomodified synthetic fluorine mica) and exfoliation [129-131]. 

---