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Simultaneous interpenetrating networks (IPNs) comprising of polymethylsilsesquioxane (PMSQ) and phenolic resole (PF) systems at various PMSQ to PF ratios (0–75% w/w PF) which formed the matrix resin for 60% w/w short silica fibre reinforced composites (SR-PMSQ-PF) are subjected to a controlled heating regime in argon atmosphere at 1500 °C to investigate the microstructure and phase evolution based on IPN composition. This study aims at giving an insight into thermal, mechanical and chemical stability of silicone-phenolic IPN composites, particularly for high temperature thermal protection applications as in aerospace. The morphology and microstructure of the pyrolysed composites are well characterized using Raman and FTIR spectroscopy, XRD and SEM-EDS and based on this a mechanism for microstructure evolution is proposed. It is inferred that the pyrolysis of SR-PMSQ-PF composites results exclusively in the formation of cristobalite silica. In addition to that, the formation of SiC is also facilitated particularly in nano dimension with increase in phenolic content, by carbothermal reduction of silica derived from PMSQ and silica fibre predominantly through solid-vapour phase reaction along the (111) crystalline plane. The systematic evaluation of microstructure and morphology of pyrolysed SR-PMSQ-PF IPN composites is useful to define specific thermal protection applications for these composites.

The epoxy resins are widely used in nuclear and aerospace industries. The certain properties of epoxy resins as well as the resistance to radiation can be improved by the incorporation of different fillers. This study examines the effect of electron beam irradiation on the thermal and mechanical properties of the epoxy composites filled with aluminum nanoparticles at percentage of 0.35 wt%. The epoxy composites were exposed to the irradiation doses of 30, 100 and 300 kGy using electron beam generated by the linear electron accelerator ELU-4. The effects of the doses on thermal and mechanical properties of the aluminum based epoxy composites were investigated by the methods of thermal gravimetric analysis, tensile test, and dynamic mechanical analysis. The results revealed that the studied epoxy composites showed good radiation resistance. The thermal and mechanical properties of the aluminum based epoxy composites increased with increasing the irradiation dose up to 100 kGy and decreased with further increasing the dose.

In this work, we investigate the morphological and mechanical properties of blends of diglycidyl ether of bisphenol-A (DGEBA) and epoxidized polystyrene–polybutadiene star block copolymer (epST3) using diamino-diphenyl sulphone (DDS) as a hardener. The epoxidation of the star block copolymer was performed using meta-chloroperoxybenzoic acid (m-CPBA). Chemical modification of the copolymer was characterized by Fourier transform infrared (FTIR) spectroscopy while the morphology of the blends was analyzed by microscopic techniques. The mechanical behavior of the blends was analyzed by recording microindentation as well as impact tests. It has been demonstrated that the completely macrophase-separated morphology of the blends could be dispersed into the structures comprising co-continuous networks of the block copolymer phase and the epoxy resin leading to an increment in impact strength. At the same time, the hardness and stiffness of the blends, as shown by the indentation microhardness and indentation modulus, was maintained to a pretty high level.

The influence of chemical interaction between poly(epsilon-caprolactone) (PCL) and Cloisite 10A on rheology, water permeability and antibacterial properties were subjected to detailed investigation. Mats of PCL with varying amounts of Cloisite 10A were prepared by electrospinning technique. The hydrogen bonding interaction between PCL and the organic modifier present in Cloisite 10A encourages the exfoliation/intercalation of Cloisite 10A resulting in a strong immobilized polymeric zone which was confirmed by small angle oscillatory shear experiments (SAOS). Unimpeded permeation of water through a PCL-Cloisite 10A porous nanocomposites scaffold was confirmed by different diffusion models. This strong immobilized zone or percolated network formation, aids in the elution of the organic modifier present in the nanoclay, which leads to the rupture of the cell wall of the bacteria. The antibacterial properties were tested using Gram positive bacteria and compared with the results obtained for Gram negative bacteria to test the use of our nanocomposites for wound healing applications.

We investigated the dynamics of phase separation in a bisphenol A diglycidyl ether (BADGE)-poly(trimethylene terephthalate) (PTT) blend in this study, along with its effects on the long-term mechanical properties of the blend. BADGE-PTT blends with 4,4′-diaminodiphenyl sulfone were prepared by a conventional melt-mixing technique followed by curing at 180 °C for 4 h. PTT is a rapidly crystallizing polymer because of its unique stereochemistry. The crystalline fraction of PTT is incompatible with BADGE, whereas the amorphous fractions are miscible. Similarly, the blend of BADGE and PTT represented a system with a strong dynamic asymmetry. We examined the effect of the curing (crosslinking) of BADGE in the system discussed previously, with a special emphasis on the viscoelastic properties and long-term mechanical properties because they are extremely important in tuning these materials for various high-performance applications in the aerospace industry. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45059.