| Long chain nylons (such as nylon 11 and 12) have been widely used in military, machinery, electron equipments, automobiles, information and aviation industries. For example, they can be used in oil pipe; soft pipe; coatings of electric cable, wire and optical fiber; stand of bearing; precise parts of wheel; electronic machinery parts, etc. And it is well accepted that nylons with longer carbon chain give superior properties since they provide a combination of high strength and toughness, abrasion resistance, dimensional stability. However, it is a complex technology to chemically synthesize these nylons. The research for these nylons with longer chain is still a developing direction of nylon in the world. On the basis of successfully synthesizing the nylon 1212, we also synthesize nylon 1311using 1,13-tridecanedioic acid and undecanedioic acid . which can be got from light wax, as raw material in simulated industry set.The following issues have been studied in the research: First, the synthesis of the novel nylonl311; second, the physical and mechanical properties of nylonl311 were determined; third, study of melting-crystallization nylonl3U; fourth, a systematic study of the isothermal and nonisothermal melt crystallization kinetics of nylon 1311 was carried out with DSC; fifth, study on the thermal degradation process and mechanism of nylonl311;sixth, a comprehensive rheological study for nylon 1311 melt. The major conclusions,and results of the research are as following: 1.On the basis of successfully synthesizing the nylon 1212, we also synthesize nylon 1311 using 1,13-tridecanedioic acid and undecanedioic acid , which can be got from light wax, as raw material in simulated industry set. The reaction of 1,13-tridecanedioic acid with ammonia for the preparation of azelanitrile gave 1,11-dicyanoundecane in 88% yield. Catalytic hydrogenation of the dinitrile in the presence of Rayni—Ni alloy powder as catalyst gave 1,13-diaminotridecane in 88% yield. 1,11-tridecanedioic acid and 1,13-diaminotridecane were combined in a 1:1 molar ratio to produce the nylon salt in 95% yield. Melt polymerization of nylon 1313 salt gave nylon 1313 in 90.1% yield. At the same time, all the products whether the middle products or final product nylonl311 are determined by NMR and IR.The properties of nylon 1311were determined and the results were as follow:ItemsUnitsResultsStandardsSpecific gravityg/cm31.02GB/T 1033Melting point°C179.6DSCGlass transition temperatureV46.5DSCWater absorption (saturated)(23°C, 24h)*0.21GB/T 1034Tensile strengthMPa48.81GB/T 1040TensileMPa1299.96GB/T 1040modulusElongation at break%355.22GB/T 1040Impact strength-notched (Izod)kJ/m25.82GB/T 1843Bending strengthMPa55.98GB/T 9341Bending modulusMPa1387.7GB/T 9341Surface resistancea2.6xlO15GB/T 1410Volume resistancefi-cm2.4xlO14GB/T 1410Dielectric loss angle (106Hz)0.01-0.04GB/T 1411Thermal deformation temperature (1.8MPa)°c48.6GB/T 16342.The synthesized novel nylonl311 are prepared for standard samples, the physical and mechanical properties of those are determined according to ASTM Standard. The following table summarizes the physical and mechanical properties of those. As a type of novel material, it's' physical and mechanical properties are of major importance. To develop novel nylon-1311's application, it is necessary to determineits'physical and mechanical properties. From the following table, we can clearly see that the physical and mechanical properties of nylonl311 are excellent. In comparison with nylon 11 and 12, we can find that the majority of the important physical and mechanical properties of nylon 1311, such as tensile strength, impact strength-notched , bending strength and so on, are equivalent to nylon 12,but the water absorption is obviously smaller than nylon 12. Bending modulus and impact strength-notched are equivalent to nylon 11, but its' elongation at break is rather higher than nylonll's. At the same time, it has excellent electric and thermal properties. By and large, the comprehensive properties of the novel nylonl311 are excellent as a kind of novel engineering plastic.3. The morphology of melting-crystallization nylonl311was observed by PLM from Tg~- Tm. There are different spherulites as crystalline temperature changed and different crystalline conditions. The results show that the only negative spherulites and blend spherulites have been observed and we haven't observed positive spherulites and others. The behaviors of nylonl311's melting are studied by DSC. After the samples of nylonl311 are treated by different heat treatment, their melting behaviors have great change. Two melting peaks appear, and the temperature of the low melting peak is close to the annealing temperature, because of irregular crystallization. When the temperature of the crystallization become high, the only melting peak appear.4. A systematic study of the isothermal and nonisothermal melt crystallization kinetics of nylon 1311 was carried out with DSC. The results indicate that the Avrami equation can successfully describe the kinetics of isothermal crystallization processes. The Avrami exponent was determined for nylon 1311 under isothermal conditions to be 2.0 approximately, which means that the crystallization of nylon 1311 during isothermal conditions is of two-dimensional growth. The nonisothermal crystallization process of nylon 1311 was analyzed by Avrami equation modified by Jezioroy and a novel equation combining the Avrami and Ozawa equation. All the results indicate that the primary crystallization is major during the forepart and the Avrami exponent n was determined for nylon 1311 under this condition to be 4.0approximately. Following the cooling rate from 5K/min to 30K / min, the Avrami exponent n is fluctuating between 3.57 and 4.63,the changing discipline isn't obvious and the mean of five Avrami exponents under five cooling rates is 4.15. It is well known that the crystallization mechanism is homogeneous nucleation and three-dimensional growth. The Avrami exponent n isn't changing obviously as the cooling rate aincreases. Above results show that the nucleation mechanism is similar in wide range of cooling rates and at the primary time of the crystallization. 5. The TG results of nylon 1311 indicate that the thermal degradation process of nylonl311 is one-step reaction in the N2. The activation energy of the solid-state process was determined using Kissinger and Flynn - Wall - Ozawa methods, and results were 200.08 ~ 194.76kJ/mol.6.A comprehensive rheological study for nylon 1311 melt was carried out by using parallel-plate rheometer and capillary rheometer. The nylon 1311 melt showed shear-thinning behavior for all discussed temperatures. The flow behavior indexes for different temperatures were obtained. The results show that nylon 1311 melt belongs to pseudoplastic liquid with the flow behavior index less than 1.The effect of temperature on the flow behavior was investigated at different shear rates. The viscous flow activation energy is higher at lower shear rate; however, the viscous flow activation energy is much lower at higher shear rate. It was found that the apparent viscosity was sensitive to temperature at lower shear stress because of higher activation energy (Ea), and the temperature affecting on the apparent viscositybecome weaker at higher shear stress because of lower activation energy ( Eo).A creep-recovery test was carried out to define the linear viscoelastic range as 10 Pa and 50 Pa for the temperature 190 and 210°CRespectively. A time-dependent response was found for the creep and recovery phases at a lower constant applied shear stress. However at higher shear stress, the creep and recovery phases were time-independent.Dynamic tests were carried out to reveal the viscoelastic behavior of the nylon 1311 melt. The linear viscoelastic range for all tested temperatures according to these tests were 50 Pa. Below the linear viscoelastic range, with angular speeds higher , theviscous response exceeds the elastic response, indicating that the viscous behavior is more predominant at a higher range of frequency. If above the linear viscoelastic range, the G" is higher than G' foever. Complex viscosity almost is constant. The viscoelastic behavior of the nylon 1311 melt depends strongly on the temperature and the applied stress over the range 190-210°C. |
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