Development and Characterization of GF/PET, GF/Nylon, and GF/PP Commingled Yarns for Thermoplastic Composites

Abstract

Commingling is becoming an important method for developing thermoplastic composites, which demonstrate significant advantages over thermoset composites in several applications including aerospace, marine, sporting, and automotive industries. Although the commingling technique has a very high potential to produce towpregs with a good blending of matrix and reinforcing fibers, it has been reported that these towpregs tend to de-mingle due to nonuniform stretching during textile and other preforming processes, leading to the segregation of stiffer reinforcing fibers and matrix-forming fibers, which in turn results in poor mechanical properties. Therefore, the current research focuses on the enhancement of stability and homogeneity of commingled yarns during subsequent processing. An attempt has been made to study the effect of the commingling process variables, namely air pressure and volume fraction of matrix-forming fibers on the structure and properties of Glass/Polypropylene, Glass/Polyester, and Glass/Nylon commingled yarns. In this paper, nips are classified into different categories based on their structure. The causes of occurrence and their effect on the commingled yarn properties are identified. Other parameters including nip frequency, nip length, and degree of interlacing are also studied in relation to the process parameters. The results show that commingling process parameters as well as the type of matrix-forming fibers significantly affect the structure and properties of commingled yarns.

Preforms and composites manufactured by novel flax/polypropylene cowrap spinning method

“…The properties of raw yarns are shown in Table 1. by means of cowrap spinning with flax and PP as raw materials, the spinning process is presented in Figure 2. Flax yarn (2), as a core yarn unwinding from flax yarn creel (1), went through a self-made spring tension (3), then the core yarn passed through another transfer roller (4) and a guide hook (5), and through the guide tube (6) into the hollow spindle (7); at the same time, the wrapped PP yarn (9) on the wrapped tube (8) wrapped outside the core yarn and went together into the hollow spindle. After the core yarn and wrapped yarn went into the hollow spindle, the two yarns had a false twist as the hollow spindle rotates.…”

Influence of test fluids on the permeability of epoxy powder bindered non-crimp fabrics

“…In this process, a thermoplastic fiber bundle or yarn is joined with a technical fiber bundle and rolled-up on a new spool for further processing. These commingled rovings are then used for classical weaving and braiding processes for textile production [23,25] ( Figure 1).…”

Experimental Investigation of Process Specific Material Behavior of Thermoplastic Hybrid Yarn Textiles

“…Thereby, the arrangement of the polymer and reinforcement filaments over the cross‐section of a single roving differs from a side by side arrangement up to a homogeneous mixing of the components. The structure of the roving influences the impregnation quality themselves, since it varies, e.g., in flow paths length of the thermoplastic material …”

“…Within this research project a mixed yarn is used, which is characterized by a homogenous distribution of glass fibers and polypropylene filaments and minimized flow paths over the cross‐section. A very good impregnation quality of the reinforcement materials as well as a high quality of the composite can be gained by applying pressures from 1–10 bar and concurrent short impregnation periods …”