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Long carbon chain thermoplastic polyamide elastomer (TPAE) with PA1212 as hard segment and polytetrahydrofuran as soft segment was synthesized successfully. Subsequently, thermoplastic polyurethane (TPU) incorporated to compensate for the high cost of TPAE and improved the foaming performance, in which a chain extender (ADR) was applied to enhance melt strength and interfacial compatibility simultaneously. The effect of ADR content on the mechanical, thermal, rheological, and foaming properties of TPAE/TPU composites were investigated in detail. It was found that the composite foams showed a more perfect cell structure, high cell density, and increased expansion ratio because of the enhanced melt strength and interfacial compatibility, when ADR was incorporated. With the increase of ADR content, the cell size and expansion ratio of the composite foams with TPU content of 30% showed a trend of first increasing and the following decreasing. The cell size reached a maximum value when the content of ADR was 2%, which was 25.81 [micro]m. Consequently, the obtained TPAE/TPU composite foams showed an outstanding compressive modulus and resilient performance to broaden its application in footwear industry. KEYWORDS chain extension, foams, interfacial compatibility, polyamide elastomer, polyurethane, orcid.org/0000-0001-5371-9615 1 | INTRODUCTION Polymer foams almost cover all fields of industrial production and life, due to the excellent properties including lightweight, high specific strength, fine thermal and sound insulation, [...]

Thermoplastic polyamide elastomers (TPAEs) were synthesized using polyamide 6 (PA6) as hard segments and polyethylene glycol (PEG) as soft segments. The prepared TPAEs showed a superior mechanical property and thermal property, which the strength and elongation-at-break reached 35.50 [+ or -] 3.54 MPa and (316.05 [+ or -] 20.58)%, respectively, when the molecular weight of soft segment was 600. Furthermore, crystallization property and microphase separation of TPAEs were also investigated in detail, having a significant influence on the foaming behavior of the obtain elastomers. Owing to the restriction of crystalline hard segments, only a few cells formed in the amorphous soft segment regions at foaming temperature of 140[degrees]C, while it transformed to larger cells with a thin cell wall at foaming temperature of 160[degrees]C and above. When the molecular weight of soft segment increased from 300 to 1000, the average cell size of the foamed TPAEs at 160[degrees]C enlarged from 28.73 to 42.17 [micro]m, while the cell density decreased from 5.26 x [10.sup.8] #/[cm.sup.3] to 4.25 x [10.sup.8] #/[cm.sup.3], both expansion ratio and shrinkage ratio increased gradually. KEYWORDS crystallization, foaming behavior, mechanical property, microphase separation, thermoplastic polyamide elastomers, 1 | INTRODUCTION Thermoplastic polyamide elastomers (TPAEs) are a new member of the thermoplastic elastomer family, composed of rubber-phase polyester or polyether and plastic-phase polyamide (PA), including PA6, PA12, PA11, [...]

Three-dimensional boron nitride/graphene nanoplatelets (3D-BN-GNP) scaffolds were fabricated using an ice-templating method and polyamide 6 (PA6)-based composites were prepared by vacuum impregnation of caprolactam monomers into the scaffolds, followed by polymerization. The BN sheets in the PA6/3D-BN and PA6/3D-BN-GNP composites display a predominant parallel alignment along the ice-crystal formation constructing thermally conductive paths. The addition of few GNPs assists the dispersion of BN sheets in the PA6/3D-BN-GNP composites and repair the broken thermal paths caused by local agglomeration of the BN sheets. Consequently, GNPs play a morphology-promoted synergistic role in the enhancement of the thermal conductivity of the PA6/3D-BN-GNP composites. The PA6/3D-BN-GNP composite prepared with 23.40 wt% BN sheets and 2.60 wt% GNPs exhibits the highest thermal conductivity of 2.80 W [m.sup.-1] [K.sup.-1], which is 833% and 33% higher than the values recorded for the pure PA6 and the PA6/3D-BN composite at BN loading of 26.18 wt%, respectively. Infrared imaging analysis revealed that the surface of the PA6/3D-BN-GNP composite has a fast response to heating and cooling, suggesting the potential of the composites in thermal management applications. KEYWORDS boron nitride, polyamide, synergistic enhancement, thermal conductivity, three-dimensional scaffold, 1 | INTRODUCTION The rapid advancement of information technology in recent years is driven by more powerful electronic devices, which are densely packed in increasingly smaller packages leading to tremendous [...]

Polyamide 6/boron nitride (PA6/BN) composites were synthesized via anionic ring-opening polymerization using [epsilon]-caprolactam as the monomer and functional boron nitride (f-BN) as the thermal conductive filler. Besides the homopolymerized PA6, some PA6 molecule chains would grow from the f-BN sheets through the 'grafting from' strategy. Compared with unfunctional hexagonal BN (h-BN), the introduction of f-BN not only improved the dispersion of f-BN in the matrix but also enhanced the interface bonding between f-BN and PA6. The homogeneous dispersion of f-BN in the PA6/f-BN composite favored the formation of the continuous thermal conductive paths or network at a low f-BN loading, and the good interface bonding reduced the phonon scattering in the interface, which improved the thermal conductivity (TC) of the PA6/fBN composite by 66.0% compared with that of the pure PA6, when only 5 wt% f-BN was added. In contrast, with the same content of unfunctional h-BN loading, the TC of the corresponding composite merely improved by 29.7%. Moreover, Young's modulus and yield strength of PA6/f-BN composites had increased obviously with the introduction of f-BN, whereas those of PA6/h-BN composites showed small fluctuation with the same contents of BN., INTRODUCTION Nowadays, polymeric materials play an increasingly important role in everyday life due to their lightweight density, low cost, and superior mechanical properties. Polymer-based composites with high thermal conductivity (TC) [...]