Synthesis And Characterization Of The Transparent Nylon Based On PACM And Its Derivative

In this paper, bis(p-Aminocyclohexyl) methane (PACM),3,3-dimethyl-bis(p-Aminocyclohexyl) methane(MACM); dodecanedioic acid (DDA) and adipic acid (ADA) has been used to synthesize a series of transparent nylon material through the high temperature melt polycondensation method. The relationship between the molecule structure such as intrinsic viscosity and tt-PACM content and the performance such as thermal properties, mechanical properties, optical properties has been studied.Research shows that the process parameters such as the equilibrium temperature, equilibrium time and equilibrium pressure has important effects on the intrinsic viscosity of the nylon product. The lower equilibrium temperature, appropriate equilibrium time and lower equilibrium pressure (higher vacuum) will be beneficial for synthesis of nylon products with high molecular weight. The optimal equilibrium temperature and pressure of NylonPACM12, NylonPACM6, NylonPACM6-12 are 270℃,300℃,300℃ and-0.08MPa,-0.08 MPa,-0.1 MPa, respectively. The optimal equilibrium time rely on the requirement of the product’s intrinsic viscosity. Similarly, the NylonMACM12 and NylonMACM6-12’s optimal equilibrium temperature and pressure are respectively 270℃,270℃ and-0.1 MPa,-0.1 MPa. It is worthy to note that the time and pressure are interworking since the equilibrium temperature is fixed.Among the PACM series of products, only NylonPACM6 and NylonPACM12 with 50% tt-PACM content are crystal materials, while the rest are in the amorphous state. The optical characterization results show that the change of the intrinsic viscosity has no effect on light transmittance. The mixed-diacid product possess the higher light transmittance of 90.5% than the corresponding single-diacid product. For NylonPACM12, the glass transition temperature increase with the increasing of tt-PACM isomer content in the range from 125℃ to 140℃. The Tg of the rest products tend to be stable. The tensile modulus and tensile strength of NylonPACM6-12 are all higher than NylonPACM12, which is respectively around 1600 MPa and 80 MPa. But the impact strength of NylonPACM6-12(7KJ/m2) is lower than that of NylonPACM12 (11KJ/m2). For NylonPACM12, tt-PACM content has an important influence on the mechanical properties. Studies have shown that the higher isomer content, the better impact resistance performance.The Tg of NylonMACM12 is between those of NylonPACM12 and NylonPACM6, at around 148℃. NylonMACM6-12’s Tg also increased with the increase of ADA content. Both the mixed or single diacid products have the higher thermal stability than PACM nylon. NylonMACM6-12’s tensile modulus and tensile strength increase with the increasing of ADA content in the molecular structure, while the elongation at break and impact strength show the opposite trend but the change of the yield strain of all the samples had no obvious difference. The transmittance of NylonMACM6-12 is the highest among the all of those product produced in this work, which could reach 91.5%.