Chain extension of thermoplastic polyamide elastomer and its foaming performance

Ma, Yufei; Wen, Hui; Xin, Chunling; He, Yadong

doi:10.1002/app.52233

Cited by 10 publications

(8 citation statements)

References 32 publications

(56 reference statements)

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“…[ 20 ] However, the content of ADR increased further to 3%, the average cells size decreased to 20.4 μm, as shown by Figure 8A 4 , owing to further increased the degree of entanglement molecular chains resulted in excessive melt strength limiting the growth of cells. [ 11,32 ] With the increase of ADR content, the expansion ratio of the composite foams showed a similar trend of first increasing and then decreasing. With the content of ADR increased to 2%, the expansion ratio reached a maximum of 4.5, due to the suitable melt strength prevented cells collapse and gas escape.…”

Section: Resultsmentioning

confidence: 86%

“…Benefiting by the physical cross-linking deriving from the crystallization of PA hard segments and microphase separation structure resulting from thermodynamic incompatibility, [7,8] TPAEs foams displays excellent fatigue resistance, bending resistance, good resilience, high expansion ratio, and low-temperature toughness. [9][10][11][12] Compared with polyamide 6 and polyamide 66 based TPAEs, long carbon chain polyamide elastomer possesses excellent chemical resistance, lower water absorption rate, and better degree of flexibility, [13,14] which the most popularly used TPAE for footwear foams are PA12-based TPAE called PEBAX. [15] However, exorbitant price makes TPAE foams only used for luxury footwear.…”

mentioning

confidence: 99%

“…[20,21] It is an effective strategy to improve the melt strength of TPAE by incorporating a chain extender (CE), which a vast array of active groups of chain extenders could react with the terminal carboxyl groups and amino groups of TPAE, contributing to the strong molecular entanglement. [22][23][24] In the report of Ma et al, [11] the incorporation of epoxy-type chain extender (KL-E4370) brought about the increase of melt viscoelasticity and the reduction of crystallinity of TPAE, which was beneficial for the microcellular foaming of TPAE. As a result, the TPAE foam with a cell size of 30 μm and a cell density of 1.5 Â 10 8 count/cm 3 was successfully fabricated.…”

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confidence: 99%

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Foaming behavior of polyamide 1212 elastomers/polyurethane composites with improved melt strength and interfacial compatibility via chain extension

Lai

Huang

et al. 2023

Polymer Engineering & Sci

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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 μm. Consequently, the obtained TPAE/TPU composite foams showed an outstanding compressive modulus and resilient performance to broaden its application in footwear industry.

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Section: Resultsmentioning

confidence: 86%

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confidence: 99%

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confidence: 99%

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Foaming behavior of polyamide 1212 elastomers/polyurethane composites with improved melt strength and interfacial compatibility via chain extension

Lai

Huang

et al. 2023

Polymer Engineering & Sci

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“…After chain extension modification, the foams with uniform closed cells were obtained. The micro-cross-linked structure was formed between TPEE and PEBAX, which had appropriate melt strength and provided support for the growth and formation of the cells, which was consistent with the analysis results of rheological properties of TPEE/PEBAX blends (Figure ). In addition, the poor compatibility and high crystallinity before the chain extension modification will also have a negative impact on the foaming of the blend, such as limited gas diffusion and uneven cells.…”

Section: Resultsmentioning

confidence: 99%

Lightweight Antistatic Thermoplastic Elastomer Blend Foam: The Foaming Behavior and Mechanical Properties

Huang

et al. 2023

ACS Appl. Polym. Mater.

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A thermoplastic polyester elastomer (TPEE) has been widely used because of its excellent impact resistance and resilience, but its melt viscosity is too low to be used in the supercritical foaming. In addition, TPEE easily generates static electricity accumulation during processing, which has a risk of fire. Herein, a thermoplastic polyamide elastomer (PEBAX) with permanent antistatic properties was blended with TPEE, and triglycidyl isocyanurate (TGIC) was used as a chain extender to improve the compatibility and melt strength of the blends. Then, the TPEE/PEBAX blends were foamed by supercritical N2, and the cell structure and mechanical and antistatic properties of the blend foam were analyzed at a density of 0.1 ± 0.001 g/cm3. The results showed that when the blending ratio of TPEE/PEBAX was 70/30, the blend foam with a uniform cell structure had the most excellent mechanical properties. The resilience and elongation at break reached 83 and 850.3%, respectively. In addition, the surface resistivity and volume resistivity were 3.21 × 109 Ω and 7.35 × 109 Ω·cm, respectively, which were significantly lower than those of the IEC 61340 standard.

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“…Cushioning composites that possess effective impact energy absorption have significant potential for applications in various industries, including automotive, personal protection, packaging, and transportation. 1 In recent years, the sports and logistics sectors have experienced rapid growth, leading to an increased demand for cushioning materials that exhibit excellent impact resistance, lightweight properties, and affordability. Traditional cushioning composites, such as foam, pearl cotton, and corrugated paper.…”

Section: Introductionmentioning

confidence: 99%

Two‐step foaming process for fabrication of flexible polyurethane foam composites with spring‐like air‐layer structure

Lou,

Chu,

Liu

et al. 2023

J of Applied Polymer Sci

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Due to its exceptional mechanical properties, polyurethane (PU) foam has found wide application in various fields. Microcellular foaming not only reduces weight but also enhances the cushioning properties of PU. However, current foaming methods have limitations in improving performance. Therefore, this study aimed to construct spring‐like sandwich‐structured flexible PU foam composites (SFFCs). These composites were prepared using a two‐step foaming method, utilizing a precise amount of polyol and isocyanate as raw materials, at room temperature (28–35°C). In the preparation process, warp‐knitted spacer fabrics (WKSFs) with spring‐like structures were encapsulated in the middle layer, while the top and bottom layers consisted of PUF (flexible PU foam with different ring radius differences) formed through the foaming process of polyol and isocyanate. The study focused on investigating the influence of the ring radius difference (r = 1, 1.5, 2) and the two‐layer layout (staggered, diagonal, overlapping) of the WKSFs on the compression and cushioning properties. The experimental results revealed a significant improvement in the mechanical properties of the PU with the incorporation of WKSFs. Particularly noteworthy was the excellent cushioning performance exhibited by the two‐layer WKSFs sample, RPUS‐1, in the dynamic impact test. RPUS‐1 absorbed 94.3% of the energy and reduced the impact value to 3921 N, which is 848 N (17.7%) lower than that of PU foam. Furthermore, even after 20 cycles of compression testing, the SFFCs retained excellent compressive properties, with the compressive stress only decreasing from 0.34 to 0.19 MPa. In conclusion, this study expands the application of PU in cushioning, demonstrating their potential in providing improved cushioning properties.

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Chain extension of thermoplastic polyamide elastomer and its foaming performance

Cited by 10 publications

References 32 publications

Foaming behavior of polyamide 1212 elastomers/polyurethane composites with improved melt strength and interfacial compatibility via chain extension

Foaming behavior of polyamide 1212 elastomers/polyurethane composites with improved melt strength and interfacial compatibility via chain extension

Lightweight Antistatic Thermoplastic Elastomer Blend Foam: The Foaming Behavior and Mechanical Properties

Two‐step foaming process for fabrication of flexible polyurethane foam composites with spring‐like air‐layer structure

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