Santanu Chattopadhyay

A triple‐filler hybrid composite was synthesized based on hydrogenated nitrile butadiene rubber (HNBR) matrix reinforced by white cement (WC), blast furnace slag (SG), and conductive carbon black (CCB). Repurposing the industrial waste as fillers bestowed a semiconducting behavior at remarkably low CCB loadings of 10 phr, whereas DC conductivity values in the range of 10 ⁻⁵ S/cm were achieved—comparable to traditional systems using 40–50 phr CCB. The hybrid composites demonstrated significant improvements in electromagnetic interference (EMI) shielding (up to ~28 dB in the extended Ku band) and gamma radiation shielding (HVL of ~49 and ~60 mm for Ba‐133 and Cs‐137, respectively) compared to the base polymer. Our values outperform conventional concrete and offer a lighter, flexible alternative to steel‐based shields. Mechanical integrity was preserved across all formulations, with optimal samples exhibiting a combination of excellent tensile strength, compressive recovery, and low‐temperature flexibility. Morphological analysis confirmed the presence of interconnected filler networks and enhanced interfacial polarization, critical to the observed multifunctionality. This work establishes a pathway toward leveraging synergistic interactions between industrial waste fillers and minimal conductive additives to obtain composites having applications in next generation lightweight shielding technologies, wearable electronics, and sensors.

The essential prerequisite of a vascular conduit is to provide a conducive, healthy lumen interface to the flowing blood within it. The persistent problem of late thrombosis, coagulation cascade activation, and vessel occlusion is pertinent in commercial and small-diameter vascular grafts (SDVG) (<6 mm diameter), upon coming in contact with blood flow. The above critical issues are overcome by providing an anticoagulant and antithrombotic coating to the lumen surface. This study explored the grafting of heparin on the polycaprolactone (PCL)–silk fibroin (SF) composite fabricated as emulsion electrospun core–shell fibers, followed by O2 plasma modification and silanization with 3-(aminopropyl) triethoxysilane (APTES). The density of heparin on PSH5 surfaces was ∼18.43 µg/cm2, sufficiently higher than in previous studies. Heparin-grafted fibers (PSH3 and PSH5) exhibited exceptional hemocompatibility with hemolysis % of (∼0.2 ± 0.003), maintaining a platelet discoid shape (∼3.5–3.9 µm diameter) without platelet activation/aggregation and conserving disc-shaped RBC morphology without apoptosis (∼5.6–5.8 µm diameter). PSH5 fibers further supported human umbilical vein endothelial cell (HUVEC) growth and proliferation on their surfaces with % cell viability of 121.8% after 5 days, with observation of the CD31 + HUVEC confluent monolayer in in vitro studies for 12 days. Subcutaneous in vivo implantation of PSH5 also depicted sufficient muscular layers and collagen deposition after 60 days of implantation with neovasculatures.

Thermoplastic polyurethane (TPU) envelope materials used in lighter‐than‐air (LTA) vehicles are susceptible to degradation from ultraviolet radiation, ozone exposure, heat, and humidity, leading to deterioration in mechanical performance and service life. In this study, TPU‐based hybrid nanocomposites containing 3 wt.% octamethyl polyhedral oligomeric silsesquioxane (OMP‐POSS), bis (2,2,6,6‐tetramethyl‐4‐piperidyl) sebacate (HALS), and 3‐mercaptopropyl trimethoxy silane (MPTMS) were developed and optimized to improve environmental durability. The influence of HALS and MPTMS loading on thermal stability, morphology, viscoelastic behavior, and aging resistance was systematically investigated. The optimized formulation U2S0.9 exhibited the highest thermal stability, with an onset degradation temperature of 239.5°C compared to 184.4°C for the control TPU. FTIR analysis and depth profiling revealed that aging‐induced chemical modifications were primarily confined to the exposed surface, while the siloxane‐rich interfacial structure remained preserved within the bulk. Mechanical retention studies demonstrated superior aging resistance, with U4S0.9 exhibiting tensile strength retention of 133.3% and 158.3% after accelerated weathering and ozone aging, respectively. The hybrid stabilization effects of HALS, MPTMS, and OMP‐POSS effectively suppressed environmental degradation, demonstrating the potential of these hybrid nanocomposites as durable protective envelope materials for aerostat and LTA vehicle applications.

Thermoresponsive shape memory polymers derived from segmented thermoplastic polyurethanes (TPUs) present a compelling integration of processability, elasticity, and programmable deformation. This study involves the incorporation of octamethyl polyhedral oligomeric silsesquioxane (OMP) into an aliphatic polyether‐based TPU through solution casting followed by melt blending to create mechanically robust shape‐memory nanocomposites. This study systematically examined the effect of OMP loading (1–4 wt.%) on microphase morphology, short‐range ordering, thermomechanical behavior, and shape‐memory performance. Microscopic studies and X‐ray diffraction studies indicate that low to intermediate OMP contents facilitate homogeneous dispersion and inhibit hard‐segment aggregation, whereas higher loadings lead to OMP–OMP self‐association and the formation of rigid OMP‐rich domains. DSC and DMA indicate that OMP influences segmental dynamics through modifications in hydrogen bonding, heat‐capacity increments, and elevation of storage modulus, thus adjusting elastic energy storage and dissipation. The nanocomposite with 2 wt.% OMP demonstrated the optimal balance of tensile strength, extensibility, and viscoelastic contrast, achieving a peak shape recovery of 97.0% with values decreasing to 80.2% over five repeated cycles alongside significant shape fixity of 94.0%–84.0%. Cyclic thermomechanical tests demonstrated enhanced durability and recovery retention for this composition, while thermally triggered recovery experiments revealed rapid and complete recovery, underscoring its responsiveness to practical stimuli. This study demonstrates that melt‐blended TPU/OMP nanocomposites function as effective thermally programmable shape‐memory materials and clarifies the structure–property relationships that influence their performance.

This study focuses on the evaluation of the mechanical, thermal, gas barrier, and electrical properties of segmented polyester-based TPU coatings with a low loading of 2D- graphene nanofillers, namely graphene oxide (GO), reduced graphene oxide (RGO), and graphene nanoplatelets (GNP), respectively. TPUs have a unique segmented structure featuring soft and hard segment alternation, which contributes to their inherent tailor-made flexibility and strength. Incorporation of the graphene fillers enhanced the thermal stability, mechanical performance, and electrical conductivity by virtue of their large surface area. TPU at 0.5 wt% GO displayed a tensile strength of 30.4 MPa and 800% elongation at break while preserving flexibility. GO and RGO decreased oxygen permeability by approximately 70% and 46%, respectively. RGO exhibited enhanced mechanical and electrical properties attributed to reduced oxygen content and increased π–π interactions. At 1.0 wt%, GNP established a percolated conductive network exhibiting an electrical conductivity of approximately 9.0 × 10 ^− 5 S/m, which is 66% greater than that of RGO filled composites. The various oxidation levels and morphologies of these fillers provide unique benefits, facilitating multifunctional TPU nanocomposites. This study clarifies the interactions between graphene and TPU, contributing to applications such as flexible electronics, packaging, protective coatings, and lighter-than-air vehicles.