Flexibility 1212 Preparation And Characterization Of Nylon

Preparation of polymer composites is one of the important methods to realize high performance of polymer materials. In this paper, different toughness agents were used to prepare 5 nylon1212 blends, and the properties of nylon1212/ SEBS-g-MA/DIDP/BSBA blends were studied systematically. A lot of valuable information was obtained that can be used for development of nylon1212 composites. The main works and conclusions were listed as following:1. 5 nylon1212 blends were prepared by using different toughness agents. The results of mechanical properties study indicate that nylon1212/DIDP/BSBA blends have excellent impact strength, and the blends have good retention of tensile and flexural strength. The impact strength of nylon1212/SEBS-g-MA/DIDP/BSBA blends enhance obviously with the increase of SEBS-g-MA content. When the content of SEBS-g-MA up to 10%, the impact strength is 89.3kJ/m2, which is 20 times as large as pure nylon1212 and the tensile strength is 0.9 times as that of nylon1212. The impact strength of nylon1212/MBS/ Epoxy blends enhance is not very remarkable, but the blends have superior synthetic mechanical properties.2. The crystal behavior of nylon1212 blended with SEBS-g-MA/ DIDP/BSBA was investigated. PLM observation showed that SEBS-g-MA function as a nucleating agent to cause the formation of small spherocrystal of nylon1212.WAXD study showed that the toughness agent influenced on the crystal structure of nylon1212 unit cell. The α crystal form transformed into the β when SEBS-g-MA content increases. DSC study showed that the additive of SEBS-g-MA change the crystalline ability of nylon 1212. The reason of the obvious rising of the crystal temperature in the blends of nylon1212/ SEBS-g-MA is that the SEBS-g-MA acts as nucleating agents. The none-isothermal crystallization behavior of nylon1212 blends were also discussed by using revised Avrami method. The result showed that the half-time of crystallization t1/2 of nylon1212 blends is reduced and toughness agents play a role as nucleating agent of nylon1212.3. The dynamic-mechanical properties of nylon1212/SEBS-g-MA/DIDP/ BSBA blends were investigated by means of dynamic-mechanical analyzer. The resultsshow that the storage modulus E' and glass transition temperature Tg of nylon 1212 blends decrease nonlinearly as the weigh fraction of SEBS-g-MA increase, and the loss modulus E" increase with the increase of SEBS-g-MA content; The a transition activation energy of nylon1212 blends decrease, but the values increase as the weigh fraction of SEBS-g-MA increase.4. Rheological properties of nylon1212 blends were studied by using Haake rheometer. The effect of shear rate, shear stress and temperature on the apparent viscosity of nylon1212 blends were discussed. The results showed that the non-Newton index n<1, and decreased with the increase of the toughness agent contents. Apparent viscosity decreases with the increase of the temperature. With increasing shear rate and shear stress, shear thining of blends were observed clearly. A creep and creep-recovery test were carried out to discover the viscoelastic properties at the temperature range 220-240℃.The viscoelastic behavior of the nylon1212 blends depend strongly on the temperature and the applied stress were observed. The viscous behavior of nylon1212 blends is more predominant than that of pure nylon1212. Dynamic tests showed that the storage modulus G' and loss modulus G" all increase with the increase of frequency ω .The complex viscosityη* decrease with the increase of frequency. At a certain frequency, the complexviscosity η* increase greatly with the increase of the SEBS-g-MA content.5. The morphology of nylon1212/SEBS-g-MA/DIDP/BSBA blends were studied using SEM technique. It was found that the toughness mechanism of nylon 1212/SEBS-g-MA/DIDP/BSBA blends belong to the mechanism of "craze-shear bands" toughness. The fracture of blends is yielding fracture, and belongs to "slip-stick" fracture.