This work investigates the melt spinning process of the metallocene cyclic olefins copolymer (mCOC), which had never been successfully developed before. The shear-viscosity examination reveals that the mCOC has a mild shear thinning tendency due to the presence of cyclic olefins, but is very sensitive to the temperature variation. The optimal melt extrusion temperature for the mCOC is found between 320 and 330°C. The mCOC is known to have high Tg, which would cause early solidification, seriously broken filaments, and winding interruption during the melt spinning process. Accordingly, the traditional spinning process employing an air-quenching system at 18°C for polyolefins, such as polypropylene and polyethylene, is inappropriate for the mCOC. Experimental results reveal that in melt spinning of the mCOC, it is necessary to install a heating board of 1.4 meters length and heated up to 180°C to assisting with the spin draw ratio of the mCOC. The elongation rheology of the mCOC was found to be greatly affected by the presence of cyclic olefins. The optimal spinning speed is 1500 m/min. In such a speed, the spin draw ratio of the mCOC is 90, which is higher than the literature value of 10[11], but still far smaller than 200–400 for typical linear polymers. Experimental results suggest that hot drawing, with a drawing ratio of 1.15 and godet temperature of 200°C, can yield yarn with optimal tenacity of 1.4 g/den. Birefringence observations indicate that mCOC yarn, even via melt spinning and hot drawing, does not exhibit any bulk orientation. The result of X-ray diffraction implies that hot drawing can enhance the formation of nano-crystals with an average size of approximately 6.5 nm. This takes place on the short linear olefin chains among the cyclic segments. The degree of crystallization increases slightly as the godet temperature increases.
A CNE (cresol-novolak epoxy) composite of CCL (copper-clad laminate), comprising glass fabrics and mCOC (metallocenebased cyclic olefin copolymer) fabrics with various laminated structures, was fabricated and its dielectricity at high frequency was examined. The dielectric constant, D k , at 5 GHz of a conventional glass/CNE composite is 4.0, whereas that of a seven alternately layered mCOC/glass/CNE composite with an externally facing mCOC layer is 2.3. In the same manner, the former has a loss tangent, D f , of 0.035, whereas the latter has a loss tangent, D f , of 0.007. In addition, the decrease of D f with increasing mCOC content is not linear but logarithmical. The T g (glass transition temperature) and scanning electron microscope results reveal the good compatibility of the mCOC and CNE at the interface between them. An optimal compression process, which involved a pressure of 20 kg/cm 2 at 185 C for 120 min, was followed by setting at 120 C for 30 min, to relax the residual stress that built up inside the mCOC prepregs, with the purpose of fabricating a mCOC/glass/CNE CCL without any tilt angle. The worsening of the flame retardancy that is caused by replacing some of the nonflammable glass layers with organic mCOC layers can be overcome by blending more 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide dicyandiamide hardener into the CNE matrix. The highest flameretardant standard, of grade UL 94 V0, can be achieved with a phosphorus content of the glass/CNE and glass/ mCOC/CNE CCLs of 8000 and 12,500 ppm, respectively. Briefly, a flame-retardant mCOC/glass/CNE composite of CCL operated at high frequency is successfully produced.
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