Structure and Morphology of Thermoplastic Polyamide Elastomer Based on Long-Chain Polyamide 1212 and Renewable Poly(trimethylene glycol)

Study on Chain Extension Blending Modification and Foaming Behavior of Thermoplastic Polyamide Elastomer

In order to improve the melt foaming properties of thermoplastic polyamide elastomers and reduce the shrinkage rate of foamed materials, acid anhydride chain extenders SMA (styrene maleic anhydride copolymer) are used in this paper to in situ reactive blending thermoplastic polyamide elastomers (TPAE) and polyamide 6 (PA6). The rheological and crystalline properties of the modified samples were characterized by a rotational rheometer and differential scanning calorimeter, and the melt batch foaming experiment with CO₂ as the foaming agent was carried out. The results showed that the melting enthalpy of modified TPAE reduced with the addition of content of PA6, which implied that the crystallinity of the hard phase of the system was depressed. Nevertheless, the reduction of crystallinity was beneficial to improve the penetration of gas and reduce the effect of the pressure difference inside and outside the cell on foam shrinkage. Additionally, the microcross-linked structure formed with the increase of PA6 content enhanced the storage modulus of modified TPAE, which could accelerate recovery of strain. The foaming temperature zone and recovery performance of all modified TPAE samples were significantly improved. The overall shrinkage rate was reduced to less than 10%, the maximum expansion ratio could reach 11-13 times with a more complete and uniform cell structure, and the resilience was improved by about 12%.

Structures and properties of newly synthesized semi-aromatic polyamide thermoplastic elastomers

Novel semi-aromatic polyamide based thermoplastic elastomers containing both strong and weak H-bond units were fabricated via a facile “two-step” melt polycondensation method. The structures and properties of a series of TPAEs are discussed.

Maghnite: an innovative inorganic reinforcement utilized in the synthesis of polyamide 12 nanocomposites with optimized thermal and mechanical properties

This study will contribute to the identification and understanding of the reinforcement mechanisms of thermoplastic matrices by nanofillers. This aspect is addressed through the investigation of the thermal and mechanical properties of nanocomposites consisting of a polyamide 12 (PA12) matrix crammed with organically modified clay nanoparticles. An efficient approach to the synthesis of polyamide 12 (PA12) nanocomposites was investigated; Maghnite may be a processed Algerian mineral clay which will act both as a catalyst and as an inorganic reinforcement. Two sorts of organic substances were used, labeled CTA-Mag (1CEC) and CTA-Mag (2CEC), modified by cetyltrimethylammonium (CTA) ions. However, PA12/CTA-Mag nanocomposites are characterized by various physico-chemical techniques, XRD, FTIR, TGA, scanning and transmission electron microscopy (SEM and TEM). Measurements of tensile modulus, yield strength, lastingness, elongation at break and toughness were done to assess the behavior of the mechanical properties. Furthermore, we have analyzed the consequences of the mass fraction of the fillers on the structural, thermal and mechanical properties of those nanocomposites. Specific attention has been paid to the study of relationships between the macroscopic properties and therefore the structure of nanocomposites. Thermomechanical tests showed a big improvement within the properties of the nanocomposites compared to neat PA12.

Facile Synthesis of Thermoplastic Polyamide Elastomers Based on Amorphous Polyetheramine with Damping Performance

Novel thermoplastic polyamide elastomers (TPAEs) consisting of long-chain semicrystalline polyamide 1212 (PA1212) and amorphous polyetheramine were synthesized via one-pot melt polycondensation. The method provides accessible routes to prepare TPAEs with a high tolerance of compatibility between polyamide and polyether oligomers compared with the traditional two-step method. These TPAEs with 10 wt % to 76 wt % of soft content were obtained by reaction of dodecanedioic acid, 1,12-dodecanediamine, and poly(propylene glycol) (PPG) diamine. The structure–property relationships of TPAEs were systematically studied. The chemical structure and the morphologic analyses have revealed that microphase separation occurs in the amorphous region. The TPAEs that have long-chain PPG segments consist of a crystalline polyamide domain, amorphous polyamide-rich domain, and amorphous polyetheramine-rich domain, while the ones containing short-chain PPG segments comprise of a crystalline polyamide domain and miscible amorphous polyamide phase and amorphous polyetheramine phase due to the compatibility between short-chain polyetheramine and amorphous polyamide. These novel TPAEs show good damping performance at low temperature, especially the TPAEs that incorporated 76 wt % and 62 wt % of PPG diamine. The TPAEs exhibit high elastic properties and low residual strain at room temperature. They are lightweight with density between 1.01 and 1.03 g/cm³. The long-chain TPAEs have well-balanced properties of low density, high elastic return, and high shock-absorbing ability. This work provides a route to expand TPAEs to damping materials with special application for sports equipment used in extremely cold conditions such as ski boots.