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The outermost layer of a fire proximity suit needs to conform to a strict requirement of radiant protection performance (RPP) ≥ 20s, which is indicative of its ability of offering a protection for at least 20s duration from second degree burn upon radiant heat exposure (84 kW/m2). Typically, this layer is fabricated by laminating a single‐side metallized PET (SMPET) layer with glass fabric. However, upon erosion of the deposited metal, this laminate is rendered unsuitable due to loss of reflectivity. Here, we explore the possibility of replacing the SMPET with its dual‐metallized analogue (DMPET) and determine the effect of increasing the optical density (OD) on the adherence and protection level. Metallized films with OD varying from 2.2 to 4.8 were laminated with glass fabrics of twill, satin and plain weave pattern using a silicone adhesive. The peel adhesion strength of laminates prepared using DMPET was found to be higher (1.01 ± 0.03 N/mm), as compared to SMPET (0.63 ± 0.03 N/mm) and the resulting films did not undergo delamination during flexing. Laminates prepared from satin woven glass fabric exhibited lowest flexural rigidity followed by twill and plain woven glass fabric. Protection offered by the laminate from convective heat was quantified in terms of the thermal protective performance (TPP), and the abraded laminate prepared using DMPET (OD‐4.8) was found to meet all the mandatory requirements of proximity clothing, offering an RPP of 27 s and a TPP of 62 cal/cm2 s. In comparison, SMPET laminates exhibited lower level of adhesion and offered an RPP of only 7.5 s. [ABSTRACT FROM AUTHOR]

ABSTRACT In this article, we have studied the effect of microcapsule shell material on the mechanical behavior of self-healing epoxy composites. Liquid epoxy healant was encapsulated in melamine-formaldehyde (MF) and urea-formaldehyde (UF), using emulsion polymerization technique to prepare microcapsules of different shell walls. The core content of the microcapsules, as determined by solvent extraction technique was found to be 65 ± 4%, irrespective of the shell wall of microcapsule. Morphological investigations reveal a rough texture of the spherical microcapsules, which was attributed to the presence of protruding polymer nanoparticles on the surface. Epoxy composites containing UF and MF microcapsules (3-15% w/w) were prepared by room temperature curing and their mechanical behaviour was studied under both quasi-static and dynamic loadings. The tensile strength, modulus, and impact resistance of the matrix was found to decrease with increasing amount of microcapsule in the formulation, irrespective of the shell wall material used for encapsulation. Interestingly, substantial improvement in the fracture toughness of the base resin was observed. Morphological investigations on the cracked surface revealed features like crack pinning, crack bowing, microcracking and crack path deflection, which were used to explain the toughened nature of microcapsule containing epoxy composites. Our studies clearly indicate that the microcapsule shell wall material does not play any significant role in defining the mechanical properties of the composites. In addition, presence of secondary amine functionalities in UF and MF shell wall do not interfere with the reaction of epoxy with triethylene tetramine hardener during the curing process. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40572. [ABSTRACT FROM AUTHOR]