Production of Towpregs

GF/PP pipes with dimensions of 0 80 x 2 (mm) were produced from the two semi-products using the typical filament winding conditions shown in Table 5. The use of PCTs allows a 6-fold increase of the rotational speed, compared to that used in the production of towpregs (from 5 to 30 rpm), i.e., much higher production rates are achieved. As stated before, this was the reason for the production of PCTs. 

F. W. J. van Hattum, J. P. Nunes, C. A. Bernardo (2004) A theoretical and experimental study of the production of towpreg-based long fiber thermoplastic composites. Composites Part A, in press. 

Production of Thermoplastic Towpregs and Towpreg-Based Composites... 

Figure 2. Production of pre-consolidated tapes (a) view of the die, (b) GF/PP towpreg and PCT samples.

A pultrusion head was designed, built, and mounted on a conventional 60 kN PULTREX pultrusion line (for thermoset matrix composites), thus adapting it to the production of continuous profiles made from thermoplastic matrix towpregs. The pultrusion head (Figure 11) includes three main parts (i) preheating furnace, (ii) pressurization and consolidation die, and (iii) cooling die. 

A major improvement over the previous results was obtained with compression molded composites, by enhancing the fiber-matrix adhesion small quantities of a carboxylic-acid-anhydride-modified polypropylene, Licomont AR 504 (supplied by Clariant, Portugal), were added in the coating chamber during the production of the towpregs. The results are summarized in Table 8. 

J. P. Nunes, J. F. Silva, A. T. Marques, N. Crainic, S. Cabral-Fonseca (2003) Production of powder coated towpregs and composites, J. Thermopl. Compos. Mater. 16, 231. 

Nunes, J. P., Silva, J. F., Marques, A. T., Crainic, R, Cabral-Fonseca, S., Production of Powder Coated Towpregs and Composites, Journal of Thermoplastic Composite Materials, 16 (3), (2003). 

Applied Composite Technology (ACT), Fayette, Utah, USA—manufacture composite products, a leading producer of prosthetic limbs. Also produce rifle and pistol barrels. AppUed Fiber Systems, Clearwater, Florida, USA— manufacture Towflex, which includes continuous carbon fiber powder coated with a variety of thermoplastics, such as Nylon-6, PP, PET, PES, PEI, PPS and PEEK, avaUable as a flexible towpreg suitable for hot filament winding. Acquired by Hexcel in April 2001. 

J. W. Klett, J. Albiger, D. D. Edie, G. C. Lickfield (1992) Production and evaluation of a polyimide/carbon fiber powder-coated towpreg, Proc. 7" Int. Conf. Carbon-Carbon 92, Essen, Germany, p. 683. 

Using the above described initial equipment, the amount of polypropylene powder deposit in the towpregs deeply decrease at production rate speeds greater than... 

The new fiber heating technique enables the use of higher speed rates in the GF/PP towpreg production ... 

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