Nylon fibers, moisture content

Long-fiber nylon 11 and 12 (30/50 wt% glass fiber) shows up to 200% improvement in impact, dimensional stability, good surface appearance, low moisture content and improved abrasion resistance. Table 2.4 provides short- and long-glass fiber/nylon 6/6 RPs properties at elevated temperatures. 

When A = 1, this expression reduces to Langmuir s equation for monomolecular adsorption. If 0 < A < 1, there is a finite maximum hygroscopic moisture content. While many textile fibers approach such a moisture content asymptotically at high relative humidities, some man-made fibers such as nylon and viscose appear to have well-defined maximum hygroscopic moisture contents [9]. In many cases, the coefficient k is greater than 1. Jaafar and Michalowski [8] interpret this behavior as the thermal effect of adsorption being equal to the heat of condensation only after a multimolecular layer has been formed. 

Figure 6.152 Dielectric strength vs. moisture content and temperature for BASF Ultramid A3EG6—30% glass fiber, heat stabilized Nylon 66 resin [8].

One of the most thoroughly researched applications of NIR to textile substrates is the measurement of substrate moisture content. Most of the textile moisture applications are for natural fiber products — wool, cotton, and so forth. For synthetic textile products, Elliott and coworkers [32] studied the spectral locations and the spectral influence of water on synthetic fiber spectra. Rodgers [17,33] measured the moisture content of nylon fibers by NIR spectroscopy both in the laboratory and at-line/ pseudo on-line. 

The cut pieces of the nylon polymer and composites were placed in a Cole Parmer vacuum oven at 70 °C for 24 h to remove water and moisture contents. Neat nylon-6 and nanocomposite fibers were prepared using a Brabender single screw extruder (Intelli-torque) and single hole fiber die (diameter = 0.016 inches (0.4 mm), LID ratio = 4) with the following parameters ... 

---