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Polymer foam with complex cellular structure (CCS) possessing both large cell and small cell simultaneously has lower density as well as better mechanical and thermal properties than those with mono-porous cell structure, which could be applied in the fields of packaging and construction materials. In this article, organic montmorillonite (OMMT) was introduced into chain-extended poly(butylene succinate) (CPBS) through melt blending method. CCS in the resultant CPBS samples were generated in a stainless steel autoclave using supercritical CO 2 as physical blowing agent by a cooling and two-step depressurization method. The crystallization temperature and crystallinity of CPBS increased by 4 C and 2% respectively, due to the introduction of OMMT. Exfoliated structure of OMMT and some fish scale-like OMMT were observed in the CPBS/OMMT nanocomposites. The optimum range of the first depressurization between 1 and 7 MPa for fabricating the CCS in the CPBS foams with different contents of OMMT was obtained.

In this article, a facile melt blending and solid batch foaming approach was proposed to prepare microcellular polystyrene/thermoplastic polyurethane (PS/TPU) blending foams with supercritical carbon dioxide (CO2). Compared with those of pure PS and pure TPU, an interesting phenomenon about the enhanced complex viscosity and storage modulus, as well as decreased loss factor of PS/TPU blends, was found. The solubility of CO2 in the PS/TPU blends was enhanced, owing to the CO2 solubilization effects of TPU. An interesting bimodal cell structure (BCS) was observed in the PS/TPU blending foams with the TPU content of 10, 15, and 20%. Consequently, a significant conclusion could be speculated that the generation of BCS in the PS/TPU blending system depended on not only the viscosity and morphology of the polymer blends but also the solubility and diffusivity of the CO2 as well as the type of cell nucleation. The thermal insulation property of PS foam was improved by the introduction of TPU.

In this article, a facile and green strategy of nonisothermal crystallization induction was proposed to produce nanocellular biodegradable polymer composite foams, which was demonstrated by a composite system of poly(butylene succinate) (PBS) modified by hydroxyl‐functionalized graphene (HG) and chain extender. Nanocellular foams of chain extended PBS (CPBS) and CPBS/HG composite were prepared successfully with supercritical CO2. Two significant phenomena about the preparation of nanobubbles in CPBS and CPBS/HG composite foams were found. One was that the nanobubbles generated at the temperature region of crystallization transition and the other was that chain extension played a critical function in the generation of nanobubbles. As the foaming temperature switched from 86 to 85°C, an interesting microbubble to nanobubble transition in CPBS and CPBS/HG foams was observed. Due to the generation of nanobubbles and the enhancement of volume expansion ratio, an excellent thermal insulation performance was achieved by CPBS/HG foams. J. VINYL ADDIT. TECHNOL., 26:461–474, 2020. © 2020 Society of Plastics Engineers

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