To meet the comprehensive demand for flexible microwave absorbing (MA) materials, a novel MA rubber containing homemade Polypyrrole nanotube (PPyNT) is produced based on the natural rubber (NR) and acrylonitrile-butadiene rubber (NBR) blends. To achieve the optimal MA performance in the X band, the PPyNT content and NR/NBR blend ratio are adjusted in detail. The 6 phr PPyNT filled NR/NBR (90/10) composite has the superior MA performance with the minimum reflection loss value of −56.67 dB and the corresponding effective bandwidth of 3.7 GHz at a thickness of 2.9 mm, which has the merits in virtue of achieving strong absorption and wide effective absorption band with low filler content and thickness compared to most reported microwave absorbing rubber materials over the same frequency. This work provides new insight into the development of flexible microwave-absorbing materials.

In this work, rigid polyurethane materials were synthesized via a one-step polymerization method using isocyanate (MDI) and polyether polyol (4110S) as the main raw materials, with 1, 4-butanediol (BDO), 1, 6-hexanediol (HDO), diethylene glycol (DEG), and dipropylene glycol (DPG) as chain extenders. The influence of chain extender structure on the mechanical properties of rigid polyurethane was systematically investigated. The results indicate that when BDO was employed as a chain extender, the polyurethane exhibited the most uniform pore size distribution and the best mechanical properties. It was found that hydrogen bonding plays a dual role: on the one hand, it promotes microphase separation between soft and hard segments; on the other hand, it extends the molecular chains’ length, which hinders segment separation and consequently constrains its mechanical properties. Further analysis reveals that the influence of molecular chain length on mechanical properties outweighs that of polarity.

Organic room‐temperature phosphorescence (RTP) materials for flexible and aquatic applications are limited by triplet exciton instability under deformation and environmental perturbation. Here, molecular π‐conjugation engineering is integrated with polymer‐matrix confinement to enable RTP in elastomeric systems. Benzoindole derivatives with tunable π‐conjugation are synthesized and embedded into rigid PVB and flexible SEBS matrices, revealing a distinct host‐dependent mechanism. While hydrogen‐bonding‐dominated PVB exhibits a slight decrease in phosphorescence lifetime upon π‐extension, elastomeric SEBS shows a pronounced lifetime enhancement from 0.52 to 1.10 s. Theoretical calculations demonstrate that π‐extension intrinsically enhances excited‐state delocalization and improves singlet‐triplet energetic matching, whereas MD simulations reveal that physical confinement within SEBS more effectively restricts the extended chromophore and suppresses nonradiative decay. The resulting RTP elastomers sustain stable emission under 400% strain over ten cycles, support loads up to 1.5 kg, and retain phosphorescence after 2 months of seawater exposure. These features enable wearable and underwater operation, establishing a molecular‐level for mechanically adaptive and environment‐tolerant RTP materials.