Polyamide processing data

The extended situation analysis function of the process data warehouse, as described in [193], is able to provide some hints which models should be considered for this task if some of the properties of the reactor s output stream (containing Polyamide-6 and Caprolactam) are known, e.g., temperature and pressure of the mixture in the stream, the fraction of each substance in the stream, and their boiling temperatures. 

Chapter 5 shows that the application of hydrolytic enzymes is a powerful yet mild strategy to directly improve polymer surface properties (i.e. hydrophilicity) or activate materials for further processing. The surface hydrolysis of polyamides (PA), polyethyleneterphthalates (PET) and polyacrylonitriles (PAN) is discussed, as well as the mechanistic details on the enzymatic surface hydrolysis. The mechanistic data, combined with advances in structural and molecular biology, help to explain different activities of closely related enzymes on polymer surfaces. 

Analysis of the non-isothermal polymerization of E-caprolactam is based on the equations for isothermal polymerization discussed above. At the same time, it is also important to estimate the effect of non-isothermal phenomena on polymerization, because in any real situation, it is impossible to avoid exothermal effects. First of all, let us estimate what temperature increase can be expected and how it influences the kinetics of reaction. It is reasonable to assume that the reaction proceeds under adiabatic conditions as is true for many large articles produced by chemical processing. The total energy produced in transforming e-caprolactam into polyamide-6 is well known. According to the experimental data of many authors, it is close to 125 -130 J/cm3. If the reaction takes place under adiabatic conditions, the result is an increase in temperature of up to 50 - 52°C this is the maximum possible temperature increase Tmax- In order to estimate the kinetic effect of this increase... 

Taking into account the crystalline character of the aliphatic polyamides, the second peak is given not only hy the polymerization s heat but also contains the amount of heat corresponding to the crystallization of the separated polymer. It is very difficult to discern between heat of propagation and crystallization, respectively, since the two processes occur almost concomitantly. Consequently, additional off-line data, i.e., gravimetric and DSC were used in order to bring about the deconvolution of the overall heat. Figure 5. 

Similar data come from processing of polyamide-6 with glass fibers. Diameter swell, thickness swell, and weight swell were all substantially decreased by the... 

Several detailed analyses of the diffusion process in both rubbery polymers and in hindered glasses are offered in Chapter 2 (28). Approximate molecular interpretations have been offered for the parameters in these models (25). Nevertheless, more work is needed to verify any molecular scale connection between such parameters and the structures and motions of the polymer backbone. Spectroscopy and molecular modeling of the differences in segmental motions in a systematically varied family of polymers, e.g, the polyesters, or polyamides, can offer insight in some cases. Unfortunately, the exact segmental motions involved in the diffusive process are only partially understood, so one must be cautious about drawing conclusions based on such studies unless they are supported by actual complementary transport data. Hopefully the structure-property results presented in this book will further stimulate thinking to improve the connection between spectroscopically sensed motions, and diffusion to complement the correlations based on specific free volume in Chapters 5 S 7 (50,51). ... 

The impedance plots for the composite HR95 membrane are shown in Figure 2.3, where two different contributions associated with the membrane (m) and the electrolyte solution between the electrodes and the membrane surfaces (e) can clearly be observed. To check this assumption, the impedance data obtained with the electrolyte alone, without any membrane in the measuring cell, are also plotted in Figure 2.3. As can be observed, a parallel RC circuit with only a relaxation process and a maximum frequency of around 10 Hz (similar to that in Figure 2.1) was obtained for the electrolyte solution measured alone (R C. The circuit associated with the composite polyamide/polysulfone HR95 membrane shows two subcircuits. 

In both types of continuous systems the maximum processing speed ( line speed ) is determined by the required residence time in the plasma to get the proper treatment. The present data show that, for reasonable power densities and existing equipment, clean polymers (e.g. polyethylene, polyimide, and polyamide) can be treated in less than 10 seconds residence time. This gives a line speed of 150 m/min (500 ft/min) or more. 

Gibson and coworkers [2] emphasized that the preheating section of their thermoplastic pultrusion process was of crucial importance to a successful operation. Besides the results achieved with CF/PEEK tapes, these authors presented a wide range of interlaminar shear strength (ILSS) data for pultrudates from glass fiber (GF)/polyamide 12 (PA12) tapes. 

These experimental data show that the ratio A2 /Aj = R is approximately constant for various periods of irradiation of the film. The author explains all these facts by the following scheme of the radical chain process of polyamide photooxidation ... 

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