Preparation, Properties Research Of Polyamide 11 And Its Composites

Polyamide 11 (PA11) is a kind of biobased material which stems from castor oil. Also, PA 11 is an engineering plastic with excellent performance, such as high low-temperature impact strength, low water absorption, good chemical resistance, low melting temperature, ect, which has played a vital role in many industries. However, the disadvantages of PA 11 which include the complexity of the production process, the high price and the flammability hinder its widely used. So, the resin has been difficult to meet the development of market and industry. To solve these problems, the PA 11 resin was synthesized with 10-undecylenic acid and its composites were prepared with aminopropyl isobutyl-polyhedral oligomeric silsesquioxane (APOSS) and expandable graphite (EG). The main contents are as follows:1. The PA 11 was synthesized by bromination, amination and melt polycondensation using 10-undecylenic acid as raw materials. The PA 11 resin was investigated by FTIR, TGA, intrinsic viscosity, DMA, mechanical analysis, respectively.2.PA11/AP0SS nanocomposites were prepared with APOSS and 11-amino undecanoic acid of different ratio by in-situ polymerization, and the composites ware investigated by FTIR, DMA, XRD, intrinsic viscosity, mechanical analysis, respectively. The isothermal crystallization behavior and melting behavior of nanocomposites were also studied. The results showed that, compared to the pure PA11 resin matrix, we got the lower intrinsic viscosity and water absorption, the higher dynamic storage modulus and the more toughened and enhanced of composites.3.The PA 11/EG composites were prepared with expandable graphite (EG) by melt blending. The composites ware characterized by TGA, LOI, UL94v, mechanics performance testing, etc. The results showed that, when the addition was 15wt%, the composites reach the V-0 of vertical flame rating and thermal stability were increased. The EG was modified with silane coupling agent (KH550) and octamethacryl polyhedral oligomeric silsesquioxane (MA-POSS). The modified EG (POSS@EG) were successfully prepared and characterized by scanning electron microscopy (SEM), Raman, FTIR, TGA. The PA11/MEG and PA11/PEG composites were prepared with the modified EG and characterized by mechanical properties, LOI, UL94v, SEM, XPS, etc. The results showed that flame retardancy and mechanical properties of the PA11/MEG and PA 11/PEG composites were further enhanced than PA11/EG composites. Furthermore, the structure of char layers of PA11/POSS@EG composite become more compact and intensity because of the worm-like structure is difficult to destroy.