The present invention concerns an impregnated fibrous material comprising at least one continuous-fiber fibrous material in the form of a roving or a plurality of parallel rovings and at least one thermoplastic polymer matrix, characterized in that said at least one thermoplastic polymer is an amorphous or semi-crystalline polymer having a glass transition temperature such that Tg40 C., especially Tg100 C., in particular 120 C., the fiber content of said impregnated fibrous material being from 45 to 65% by volume, preferably from 50 to 60% by volume, especially from 54 to 60% by volume, the number-average molecular mass Mn of said thermoplastic polymer being from 11,000 to 25,000 g/mol, the melt viscosity of said thermoplastic polymer being from 80 to 1500 Pa.Math.s, as measured by plane-plane rheology at 1 Hz and 2% deformation, at a temperature of Tg+220 C.

The present invention relates to a polyamide resin having a main chain having a structure in which two polyamide segments are linked in an alternating way, a preparation method thereof, and a polyamide film and resin laminate including the same.

A laminated film having a resin layer laminated on at least one surface of a base film. The laminated film is characterized by: the base film being a semi-aromatic polyamide film that has been at least uniaxially stretched; the resin layer containing fine particles; the thermal shrinkage factor in the longitudinal direction S.sub.MD and the thermal shrinkage factor in the width direction S.sub.TD of the film measured under conditions of 250 C.5 minutes each being 1.0 to 1.5%; the tensile elongations at break in the longitudinal direction and in the width direction each being 70% or more; and the haze being 3% or less.

Exemplary embodiments provide systems, devices and methods for the fabrication of three-dimensional polymeric fibers having micron, submicron and nanometer dimensions, as well as methods of use of the polymeric fibers.

The present disclosure discloses a preparation method for an internal laser-induced carbonization layer of aramid fiber resin matrix composite material. The surface of sample of aramid fiber resin matrix composite material is wiped with anhydrous ethanol; the sample of aramid fiber resin matrix composite material was placed on the laser sample platform, and the defocusing amount between the laser focus and the upper surface of the sample was negative. Infrared picosecond laser was used to scan the sample of aramid fiber resin matrix composite material for several times. Since the laser absorption rate of the surface epoxy resin was very low, most of the laser energy passed through the epoxy resin layer and directly acted on the internal aramid fiber. The laser carbonized the internal aramid fiber without damaging the surface resin, and formed a carbonized line along the laser scanning path to realize the conductivity of aramid fiber resin matrix composite. The conductive function can replace the traditional wire in space equipment, which is helpful to promote the lightweight design of spacecraft and save a lot of space inside, and has potential application value for aircraft in electromagnetic wave stealth.

The present invention provides a polyamic acid aqueous solution composition capable of polymerizing polyamic acid in water rather than in an organic solvent, as well as achieving a high imidization rate during low-temperature curing.

A resin powder for solid freeform fabrication has a 50 percent cumulative volume particle diameter of from 5 to 100 m and a ratio (Mv/Mn) of a volume average particle diameter (Mv) to the number average particle diameter (Mn) of 2.50 or less and satisfies at least one of the following conditions (1) to (3): (1): Tmf1>Tmf2 and (Tmf1Tmf2)3 degrees C., both Tmf1 and Tmf2 are measured in differential scanning calorimetry measuring according to ISO 3146. (2): Cd1>Cd2 and (Cd1Cd2)3 percent, both Cd1 and Cd2 are measured in differential scanning calorimetry measuring according to ISO 3146, and (3): C1>C2 and (C1C2)3 percent.

Films with optical transmittance of >80% between 400 and 750 nm and with coefficient of thermal expansion less than 20 ppm/ C. are prepared from aromatic polyamides that are soluble in polar organic solvents yet have glass transition temperatures >300 C. The films are crosslinked in the solid state by heating at elevated temperatures for short periods of time in the presence of multifunctional epoxides. Surprisingly, the optical and thermal properties of the films do not change significantly during the curing process. The temperature required for the crosslinking process to take place can be reduced by the presence of a few free, pendant carboxyl groups along the polyamide backbones. The films are useful as flexible substrates for electronic displays and photovoltaic devices.

A polyamide-based resin melt obtained by melt-kneading a base resin, an organic compound-based additive (A), and an iodide-based additive (X) is granulated to prepare polyamide-based resin particles. The polyamide-based resin particles are expanded by using a physical blowing agent to produce polyamide-based resin expanded beads. The polyamide-based resin expanded beads are in-mold molded to produce a polyamide-based resin expanded molded article. The organic compound-based additive (A) is made of a hindered phenol-based compound and/or an organophosphorus-based compound. The iodide-based additive (X) is made of copper iodide, or copper iodide and potassium iodide.

The present invention relates to a polymer powder for the manufacture of articles by 3D printing, in particular by sintering, comprising a thermoplastic polymer, antioxidants, and a particular metal oxide, metal hydroxide and/or hydrotalcite, having improved thermal stability, improved recyclability and improved consistency of mechanical properties of the sintered parts.

The invention also relates to a process for preparing this powder and to the use thereof in a process for manufacturing by sintering, and to the articles manufactured from said powder.