Poly(vinylidene Fluoride) Composite Foam With Enhanced Mechanical and Thermal Insulation Properties via Supercritical CO 2 Foaming and Dual‐Filler Design

Poly(vinylidene fluoride) (PVDF) foam has attracted significant attention owing to its advanced thermal management and lightweight structural applications. However, the crystallization behavior and insufficient melt elasticity of pure PVDF hinder efficient foaming and performance enhancement. Herein, we report the incorporation of cellulose nanocrystal (CNC) and fluorosilane‐modified talc (FST) into the PVDF matrix through melt compounding, and the preparation of composite foam samples via supercritical carbon dioxide foaming. The effects of fillers and contents on foaming behavior and comprehensive PVDF properties were systematically investigated. CNC and FST acted as effective heterogeneous nucleating agents, promoting the phase transformation of PVDF from α ‐phase to β ‐phase. CNC and FST formed a multiscale heterogeneous nucleation network, which enhanced melt viscoelasticity, effectively regulated cell evolution, and achieved an optimized balance between the nucleation efficiency and cell growth. Compared with F‐PVDF (foam PVDF), F‐PVDF/CNC‐1/FST‐1 exhibited a β ‐phase content of 86.0%, while its specific compressive modulus and strength increased by 163.1% and 230.8%, respectively. It also exhibited a low thermal conductivity of 0.0308 W m −1 K −1 . This study provides an effective structural design strategy for developing lightweight, high‐strength PVDF composite foam samples with excellent thermal insulation performance.