| 摘要 |
<p>Waterleaf or unsized paper is prepd. from an aq. dispersion of fibrids and staple fibres of a polyarylene oxadiazole, in which the staple fibres have not been dried in the form of spun fibres; the paper is finally dried. Papers with Elmendorf tensile break >1.5 kg/m2 and tensile yield >20 kg/cm width/kg/m2 are obtd. These values may reach >3 kg/kg/m2 and >26 kg/cm width/kg/m2 (I) is e.g. poly- (2',6'-naphthylene)-2,5-(1,3,4-oxadiazole , or poly-1',4'- or 1',3'-phenylene-2,5-(1,3,4-oxadiazole). The fibrids are obtd. by subjecting the freshly pptd. or swollen polymer to strong shearing and/or beaten action. Filaments are obtd. by extruding a soln. of the polymer in H2SO4 or oleum into an aq. pptn. bath; the filaments are cut to the required staple length and are kept in a swollen, undried state before being mixed with the fibrids. The ratio of fibrids:filaments in the paper compsn. is 10:90-90:10.</p> |
