摘要:
A nonwoven fabric is provided having a plurality of semi-crystalline filaments that are thermally bonded to each other and are formed of the same polymer and exhibit substantially the same melting temperature. The fabric is produced by melt spinning an amorphous crystallizable polymer to form two components having different levels of crystallinity. During spinning, a first component of the polymer is exposed to conditions that result in stress-induced crystallization such that the first polymer component is in a semi-crystalline state and serves as the matrix or strength component of the fabric. The second polymer component is not subjected to stress induced crystallization and thus remains in a substantially amorphous state which bonds well at relatively low temperatures. In a bonding step, the fabric is heated to soften and fuse the binder component. Under these conditions, the binder component undergoes thermal crystallization so that in the final product, both polymer components are semi-crys talline.
摘要:
A process for the production of polyacrylonitrile-base precursor fiber for carbon fiber production which comprises spinning a spinning dope containing a polyacrylonitrile-base polymer having a limiting viscosity of 2.0 to 10.0 in a concentration of 10 to 25% by weight by a wet spinning method or a dry-wet spinning method, subjecting the obtained fiber to dry and heat treatment, and then steam-stretching the resulting fiber, wherein the extrusion linear speed of the polyacrylonitrile-base polymer from spinnerets is 2 to 15 m/min; and a carbon fiber which is produced by firing the polyacrylonitrile-base precursor fiber obtained by the process and which has a strand tensile modulus of 320 to 380 GPa and a conduction electron density of 3.0 x 10 19 to 7.0 x 10 19 spins/g as determined by electron spin resonance.
摘要:
In one embodiment is provided a polymer blend of poly(vinyl acetate) (PVAc) and poly(acrylic acid) (PAA), wherein the poly(vinylacetate) is present in an amount ranging between about 20 wt % and about 80 wt %, and poly(acrylic acid) is present in an amount ranging between about 80 wt % and about 20 wt %, based on the total weight of the blend. In another embodiment is provided a fiber produced from this polymer blend, and which has cells therein. In another embodiment is provided a flavorant release material comprising the porous fiber disclosed herein, and one or more flavorants disposed in a longitudinally extending core within the fiber. In another embodiment is provided a polymer fiber membrane containing a hollow, porous fiber formed from the polymer blend disclosed herein. In another embodiment is provided a filter containing the fiber described herein. In another embodiment is provided a process for producing the fibers disclosed herein by addition of the polymers to an extruder or blender, and extruding or melt spinning the mixture into a fiber containing cells therein.
摘要:
A large sized bulk crystal is produced which allows to cut out a practical size of crystal substrate. The gallium nitride crystal has features in which a length L of c-axis is 9 mm or more, a crystal diameter d of a cross section orthogonal to the c-axis is 100 µm, and a ratio L/d of the length L of the c-axis and the crystal diameter d of the cross section orthogonal to the c-axis is 7 or more. By enlarging this elongated needle-like crystal, a bulk crystal with a large volume can be produced, and a large sized bulk crystal can be produced which allows to cut out a practical size of crystal substrate.
摘要:
A polyphenylene sulfide resin composition which comprises: 100 parts by weight of a resin composition comprising (a) 99-60 wt.% polyphenylene sulfide resin and (b) 1-40 wt.% at least one noncrystalline resin selected among polyetherimide resins and polyether sulfone resins, the sum of (a) and (b) being 100 wt.%; and 0.1-10 parts by weight of (C) a compound incorporated therein which has one or more groups selected among epoxy, amino, and isocyanate groups. The polyphenylene sulfide resin composition is characterized by having a morphology in which the noncrystalline resin (b) forms an island phase and the noncrystalline resin (b) has a number-average dispersed-particle diameter of 1,000 nm or smaller. This composition has highly excellent toughness, less generates a gas upon thermal melting, and has excellent processability.